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| Total Power Solution for Portable Applications General Description The AAT2554 is a fully integrated 500mA battery charger, a 250mA step-down converter, and a 300mA low dropout (LDO) linear regulator. The input voltage range is 4V to 6.5V for the battery charger and 2.7V to 5.5V for the step-down converter and linear regulator, making it ideal for applications operating with single-cell lithiumion/polymer batteries. The battery charger is a complete constant current/constant voltage linear charger. It offers an integrated pass device, reverse blocking protection, high accuracy current and voltage regulation, charge status, and charge termination. The charging current is programmable via external resistor from 15mA to 500mA. In addition to these standard features, the device offers over-voltage, current limit, and thermal protection. The step-down converter is a highly integrated converter operating at a 1.5MHz switching frequency, minimizing the size of external components while keeping switching losses low. It has independent input and enable pins. The output voltage ranges from 0.6V to the input voltage. The AAT2554 linear regulator is designed for fast transient response and good power supply ripple rejection. Designed for 300mA of load current, it includes short-circuit protection and thermal shutdown. The AAT2554 is available in a Pb-free, thermallyenhanced TDFN34-16 package and is rated over the -40C to +85C temperature range. AAT2554 Features * SystemPowerTM * * * * * Battery Charger: -- Input Voltage Range: 4V to 6.5V -- Programmable Charging Current up to 500mA -- Highly Integrated Battery Charger * Charging Device * Reverse Blocking Diode Step-Down Converter: -- Input Voltage Range: 2.7V to 5.5V -- Output Voltage Range: 0.6V to VIN -- 250mA Output Current -- Up to 96% Efficiency -- 30A Quiescent Current -- 1.5MHz Switching Frequency -- 100s Start-Up Time Linear Regulator: -- 300mA Output Current -- Low Dropout: 400mV at 300mA -- Fast Line and Load Transient Response -- High Accuracy: 1.5% -- 70A Quiescent Current Short-Circuit, Over-Temperature, and Current Limit Protection TDFN34-16 Package -40C to +85C Temperature Range Applications * * * * * * Bluetooth(R) Headsets Cellular Phones Handheld Instruments MP3 and Portable Music Players PDAs and Handheld Computers Portable Media Players Typical Application Adapter/USB Input Enable VOUTB RFB1 C OUTB RFB2 VOUTA C OUTA FB OUTA GND ISET L= 3.0H LX ADP STAT EN_BAT VINB ENB VINA ENA AAT2554 BAT System BATT+ C OUT R SET BATT- Battery Pack 2554.2007.01.1.2 1 Total Power Solution for Portable Applications Pin Descriptions Pin # 1 2, 10, 12, 14 3 AAT2554 Symbol FB GND ENB Function Feedback input. This pin must be connected directly to an external resistor divider. Nominal voltage is 0.6V. Ground. Enable pin for the step-down converter. When connected to logic low, the step-down converter is disabled and consumes less than 1A of current. When connected to logic high, the converter resumes normal operation. Linear regulator input voltage. Connect a 1F or greater capacitor from this pin to ground. Linear regulator output. Connect a 2.2F capacitor from this pin to ground. Enable pin for the battery charger. When connected to logic low, the battery charger is disabled and consumes less than 1A of current. When connected to logic high, the charger resumes normal operation. Charge current set point. Connect a resistor from this pin to ground. Refer to typical characteristics curves for resistor selection. Battery charging and sensing. Charge status input. Open drain status output. Input for USB/adapter charger. Enable pin for the linear regulator. When connected to logic low, the regulator is disabled and consumes less than 1A of current. When connected to logic high, it resumes normal operation. Output of the step-down converter. Connect the inductor to this pin. Internally, it is connected to the drain of both high- and low-side MOSFETs. Input voltage for the step-down converter. Exposed paddle (bottom): connect to ground directly beneath the package. 4 5 6 VINA OUTA EN_BAT 7 8 9 11 13 ISET BAT STAT ADP ENA 15 16 EP LX VINB Pin Configuration TDFN34-16 (Top View) FB GND ENB VINA OUTA EN_BAT ISET BAT 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VINB LX GND ENA GND ADP GND STAT 2 2554.2007.01.1.2 Total Power Solution for Portable Applications Absolute Maximum Ratings1 Symbol VINA, VINB VADP VLX VFB VEN VX TJ TLEAD AAT2554 Description Input Voltage to GND Adapter Voltage to GND LX to GND FB to GND ENA, ENB, EN_BAT to GND BAT, ISET, STAT Operating Junction Temperature Range Maximum Soldering Temperature (at leads, 10 sec) Value 6.0 -0.3 to 7.5 -0.3 to VIN + 0.3 -0.3 to VIN + 0.3 -0.3 to 6.0 -0.3 to VADP + 0.3 -40 to 150 300 Units V V V V V V C C Thermal Information Symbol PD JA Description Maximum Power Dissipation Thermal Resistance2 Value 2.0 50 Units W C/W 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time. 2. Mounted on an FR4 board. 2554.2007.01.1.2 3 Total Power Solution for Portable Applications Electrical Characteristics1 VINB = 3.6V; TA = -40C to +85C, unless otherwise noted. Typical values are TA = 25C. Symbol Description Conditions Min 2.7 VINB Rising Hysteresis VINB Falling IOUTB = 0 to 250mA, VINB = 2.7V to 5.5V No Load ENB = GND 200 1.8 -3.0 0.6 30 1.0 600 0.59 0.42 VINB = 5.5V, VLX = 0 to VINB VINB = 2.7V to 5.5V VINB = 3.6V VOUTB = 1.0V From Enable to Output Regulation 1.0 0.591 0.2 0.6 1.5 100 140 15 0.6 VINB = VENB = 5.5V 1.4 -1.0 1.0 0.609 0.2 3.0 VINB AAT2554 Typ Max 5.5 2.7 Units V V mV V % V A A mA A %/V V A MHz s C C V V A Step-Down Converter VIN Input Voltage VUVLO VOUT VOUT IQ ISHDN ILIM RDS(ON)H RDS(ON)L ILXLEAK VLinereg/VIN VFB IFB FOSC TS TSD THYS VEN(L) VEN(H) IEN UVLO Threshold Output Voltage Tolerance2 Output Voltage Range Quiescent Current Shutdown Current P-Channel Current Limit High-Side Switch On Resistance Low-Side Switch On Resistance LX Leakage Current Line Regulation Feedback Threshold Voltage Accuracy FB Leakage Current Oscillator Frequency Startup Time Over-Temperature Shutdown Threshold Over-Temperature Shutdown Hysteresis Enable Threshold Low Enable Threshold High Input Low Current 1. The AAT2554 is guaranteed to meet performance specifications over the -40C to +85C operating temperature range and is assured by design, characterization, and correlation with statistical process controls. 2. Output voltage tolerance is independent of feedback resistor network accuracy. 4 2554.2007.01.1.2 Total Power Solution for Portable Applications Electrical Characteristics1 VINA = VOUT(NOM) + 1V for VOUT options greater than 1.5V. IOUT = 1mA, COUT = 2.2F, CIN = 1F, TA = -40C to +85C, unless otherwise noted. Typical values are TA = 25C. Symbol VOUT VIN VDO VOUT/ VOUT*VIN VOUT(Line) VOUT(Load) IOUT ISC IQ ISHDN PSRR TSD THYS eN TC TEN_DLY VEN(L) VEN(H) IEN AAT2554 Description Output Voltage Tolerance Input Voltage Dropout Voltage3 Line Regulation Dynamic Line Regulation Dynamic Load Regulation Output Current Short-Circuit Current Quiescent Current Shutdown Current Power Supply Rejection Ratio Over-Temperature Shutdown Threshold Over-Temperature Shutdown Hysteresis Output Noise Output Voltage Temperature Coefficient Enable Time Delay Enable Threshold Low Enable Threshold High Enable Input Current Conditions IOUTA = 1mA to 300mA TA = 25C TA = -40C to +85C Min -1.5 -2.5 VOUT + VDO2 Typ Max 1.5 2.5 5.5 Units % V mV %/V mV mV mA mA A A dB C C VRMS ppm/C Linear Regulator IOUTA = 300mA VINA = VOUTA + 1 to 5.0V IOUTA = 300mA, VINA = VOUTA + 1 to VOUTA + 2, TR/TF = 2s IOUTA = 1mA to 300mA, TR <5s VOUTA > 1.2V VOUTA < 0.4V VINA = 5V; ENA = VIN VINA = 5V; ENA = 0V 1kHz IOUTA =10mA 10kHz 1MHz 400 0.09 2.5 60 300 600 70 65 45 43 145 12 250 22 15 600 125 1.0 0.6 1.5 VENA = 5.5V 1.0 s V V A 1. The AAT2554 is guaranteed to meet performance specifications over the -40C to +85C operating temperature range and is assured by design, characterization, and correlation with statistical process controls. 2. VDO is defined as VIN - VOUT when VOUT is 98% of nominal. 3. For VOUT <2.3V, VDO = 2.5V - VOUT. 2554.2007.01.1.2 5 Total Power Solution for Portable Applications Electrical Characteristics1 VADP = 5V; TA = -40C to +85C, unless otherwise noted. Typical values are TA = 25C. Symbol Description Conditions Min Typ Max Units AAT2554 Battery Charger Operation VADP Adapter Voltage Range Under-Voltage Lockout (UVLO) VUVLO UVLO Hysteresis IOP Operating Current ISHUTDOWN Shutdown Current ILEAKAGE Reverse Leakage Current from BAT Pin Voltage Regulation VBAT_EOC End of Charge Accuracy VCH/VCH Output Charge Voltage Tolerance VMIN Preconditioning Voltage Threshold VRCH Battery Recharge Voltage Threshold Current Regulation ICH Charge Current Programmable Range ICH/ICH Charge Current Regulation Tolerance VSET ISET Pin Voltage KI_A Current Set Factor: ICH/ISET Charging Devices RDS(ON) Charging Transistor On Resistance Logic Control/Protection VEN(H) Enable Threshold High VEN(L) Enable Threshold Low VSTAT Output Low Voltage ISTAT STAT Pin Current Sink Capability VOVP Over-Voltage Protection Threshold ITK/ICHG Pre-Charge Current ITERM/ICHG Charge Termination Threshold Current Rising Edge Charge Current = 200mA VBAT = 4.25V, EN_BAT = GND VBAT = 4V, ADP Pin Open 4.0 3 150 0.5 0.3 0.4 4.158 2.85 4.20 0.5 3.0 -0.1 6.5 4 1 1 2 4.242 3.15 V V mV mA A A V % V V mA % V Measured from VBAT_EOC 15 500 10 2 800 VADP = 5.5V 1.6 STAT Pin Sinks 4mA 0.9 1.1 V V V mA V % % 0.4 0.4 8 4.4 10 10 ICH = 100mA 1. The AAT2554 is guaranteed to meet performance specifications over the -40C to +85C operating temperature range and is assured by design, characterization, and correlation with statistical process controls. 6 2554.2007.01.1.2 Total Power Solution for Portable Applications Typical Characteristics - Step-Down Converter Efficiency vs. Load (VOUT = 1.8V; L = 3.3H) 100 1.0 AAT2554 DC Load Regulation (VOUT = 1.8V; L = 3.3H) VIN = 2.7V 90 VIN = 5.0V Output Error (%) 0.5 Efficiency (%) VIN = 3.6V VIN = 5.5V VIN = 4.2V 80 70 60 50 40 0.1 VIN = 3.6V 0.0 VIN = 5.5V VIN = 2.7V -0.5 VIN = 5.0V VIN = 4.2V 1 10 100 1000 1 10 100 1000 -1.0 0.1 Output Current (mA) Output Current (mA) Efficiency vs. Load (VOUT = 1.2V; L = 1.5H) 100 90 1.0 DC Load Regulation (VOUT = 1.2V; L = 1.5H) VIN = 2.7V Output Error (%) Efficiency (%) 80 70 60 50 40 30 VIN = 3.6V 0.5 VIN = 5.0V VIN = 5.5V 0.0 VIN = 5.5V VIN = 5.0V VIN = 4.2V 0.1 1 10 100 1000 VIN = 3.6V -0.5 VIN = 4.2V VIN = 2.7V -1.0 0.1 1 10 100 1000 Output Current (mA) Output Current (mA) Soft Start (VIN = 3.6V; VOUT = 1.8V; IOUT = 250mA; CFF = 100pF) Line Regulation (VOUT = 1.8V) 1.6 0.6 0.5 Enable and Output Voltage (top) (V) 5.0 4.0 3.0 2.0 1.0 0.0 -1.0 -2.0 -3.0 -4.0 -5.0 VEN 1.4 Accuracy (%) 1.2 1.0 0.8 0.6 0.4 0.3 0.2 0.1 0.0 -0.1 -0.2 -0.3 2.5 3.0 3.5 IOUT = 0mA IOUT = 50mA IOUT = 150mA Inductor Current (bottom) (A) VO IL Time (100s/div) 0.4 0.2 0.0 -0.2 -0.4 IOUT = 10mA IOUT = 250mA 4.0 4.5 5.0 5.5 6.0 Input Voltage (V) 2554.2007.01.1.2 7 Total Power Solution for Portable Applications Typical Characteristics - Step-Down Converter Output Voltage Error vs. Temperature (VINB = 3.6V; VOUT = 1.8V; IOUT = 250mA) 3.0 10.0 2.0 1.0 0.0 -1.0 -2.0 -3.0 -40 8.0 AAT2554 Switching Frequency Variation vs. Temperature (VIN = 3.6V; VOUT = 1.8V) Output Error (%) Variation (%) -20 0 20 40 60 80 100 6.0 4.0 2.0 0.0 -2.0 -4.0 -6.0 -8.0 -10.0 -40 -20 0 20 40 60 80 100 Temperature (C) Temperature (C) Frequency Variation vs. Input Voltage (VOUT = 1.8V) 2.0 No Load Quiescent Current vs. Input Voltage 50 Frequency Variation (%) 1.0 0.0 -1.0 -2.0 -3.0 -4.0 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 Supply Current (A) 45 40 35 30 25 20 15 10 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 85C 25C -40C Input Voltage (V) Input Voltage (V) P-Channel RDS(ON) vs. Input Voltage 1000 900 750 N-Channel RDS(ON) vs. Input Voltage 120C 100C 700 RDS(ON)H (m) RDS(ON)L (m) 800 700 600 500 400 300 2.5 3.0 3.5 4.0 85C 650 600 550 500 450 400 350 120C 100C 85C 25C 25C 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 4.5 5.0 5.5 6.0 300 Input Voltage (V) Input Voltage (V) 8 2554.2007.01.1.2 Total Power Solution for Portable Applications Typical Characteristics - Step-Down Converter Load Transient Response (10mA to 250mA; VIN = 3.6V; VOUT = 1.8V; COUT = 4.7F; CFF = 100pF) 2.0 1.9 2.0 1.9 AAT2554 Load Transient Response (10mA to 250mA; VIN = 3.6V; VOUT = 1.8V; COUT = 4.7F) 1.4 Load and Inductor Current (bottom) (200mA/div) Load and Inductor Current (bottom) (200mA/div) Output Voltage (top) (V) 1.8 1.7 1.6 1.5 1.4 1.3 1.2 Output Voltage (top) (V) VO IO ILX 1.8 1.7 1.6 1.5 1.4 1.3 1.2 VO 1.2 1.0 0.8 IO ILX 0.6 0.4 0.2 0.0 -0.2 Time (25s/div) Time (25s/div) Line Response (VOUT = 1.8V @ 250mA; CFF = 100pF) 1.90 1.85 7.0 40 Output Ripple (VIN = 3.6V; VOUT = 1.8V; IOUT = 1mA) 0.07 Output Voltage (AC Coupled) (top) (mV) Output Voltage (top) (V) 1.80 1.75 1.70 1.65 1.60 1.55 1.50 VO 6.5 6.0 5.5 5.0 4.5 20 0 -20 -40 -60 -80 -100 -120 VO 0.06 Inductor Current (bottom) (A) 0.05 0.04 0.03 0.02 Input Voltage (bottom) (V) VIN 4.0 3.5 3.0 IL 0.01 0.00 -0.01 Time (25s/div) Time (2s/div) Output Ripple (VIN = 3.6V; VOUT = 1.8V; IOUT = 250mA) 40 0.8 Output Voltage (AC Coupled) (top) (V) 20 0 -20 -40 -60 -80 -100 -120 VO 0.7 Inductor Current (bottom) (A) 0.6 0.5 0.4 0.3 IL 0.2 0.1 0.0 Time (200ns/div) 2554.2007.01.1.2 9 Total Power Solution for Portable Applications Typical Characteristics - Battery Charger Constant Charging Current vs. Set Resistor Values 1000 600 500 AAT2554 Charging Current vs. Battery Voltage (VADP = 5V) RSET = 3.24k 400 ICH (mA) ICH (mA) 100 RSET = 5.36k 300 200 100 10 RSET = 8.06k RSET = 16.2k RSET = 31.6k 1 1 10 100 1000 0 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 RSET (k) VBAT (V) End of Charge Battery Voltage vs. Supply Voltage 4.206 End of Charge Voltage Regulation vs. Temperature (RSET = 8.06k) 4.23 4.204 RSET = 8.06k VBAT_EOC (V) 6.5 4.22 4.21 4.20 4.19 4.18 4.17 -50 -25 0 25 50 75 100 VBAT_EOC (V) 4.202 4.200 RSET = 31.6k 4.198 4.196 4.194 4.5 4.75 5 5.25 5.5 5.75 6 6.25 VADP (V) Temperature (C) Constant Charging Current vs. Supply Voltage (RSET = 8.06k) 220 210 Constant Charging Current vs. Temperature (RSET = 8.06k) 210 208 205 ICH (mA) 200 190 180 170 4 4.25 4.5 4.75 5 5.25 5.5 5.75 6 6.25 ICH (mA) 6.5 VBAT = 3.3V VBAT = 4V 203 200 198 195 193 190 -50 -25 0 25 50 75 100 VBAT = 3.6V VADP (V) Temperature (C) 10 2554.2007.01.1.2 Total Power Solution for Portable Applications Typical Characteristics - Battery Charger Operating Current vs. Temperature (RSET = 8.06k) 550 3.03 500 450 400 350 300 -50 3.02 AAT2554 Preconditioning Threshold Voltage vs. Temperature (RSET = 8.06k) VMIN (V) IOP (A) 3.01 3 2.99 2.98 2.97 -50 -25 0 25 50 75 100 -25 0 25 50 75 100 Temperature (C) Temperature (C) Preconditioning Charge Current vs. Temperature (RSET = 8.06k) 60 50 Preconditioning Charge Current vs. Supply Voltage RSET = 3.24k 20.8 20.6 20.4 20.2 20.0 19.8 19.6 19.4 19.2 -50 -25 0 25 50 75 100 ITRICKLE (mA) ITRICKLE (mA) 40 30 20 10 0 RSET = 5.36k RSET = 8.06k RSET = 16.2k 4 4.2 4.4 4.6 4.8 5 RSET = 31.6k 5.2 5.4 5.6 5.8 6 6.2 6.4 Temperature (C) VADP (V) Recharging Threshold Voltage vs. Temperature (RSET = 8.06k) 800 700 600 Sleep Mode Current vs. Supply Voltage (RSET = 8.06k) 4.18 4.16 85C ISLEEP (nA) 4.14 VRCH (V) 4.12 4.10 4.08 4.06 4.04 4.02 -50 -25 0 25 50 75 100 500 400 300 200 100 0 4 4.25 4.5 4.75 5 5.25 5.5 5.75 6 6.25 6.5 25C -40C Temperature (C) VADP (V) 2554.2007.01.1.2 11 Total Power Solution for Portable Applications Typical Characteristics - Battery Charger VEN(H) vs. Supply Voltage (RSET = 8.06k) 1.2 1.1 1.1 1 AAT2554 VEN(L) vs. Supply Voltage (RSET = 8.06k) -40C -40C VEN(H) (V) VEN(L) (V) 1 0.9 0.8 0.7 4 4.25 4.5 4.75 5 5.25 5.5 5.75 6 6.25 6.5 0.9 0.8 0.7 0.6 4 4.25 4.5 4.75 5 5.25 5.5 5.75 6 6.25 6.5 25C 85C 25C 85C VADP (V) VADP (V) 12 2554.2007.01.1.2 Total Power Solution for Portable Applications Typical Characteristics - LDO Regulator Dropout Voltage vs. Temperature 3.2 AAT2554 Dropout Characteristics 540 Dropout Voltage (mV) 480 420 360 300 240 180 120 60 0 IL = 300mA 3.0 IOUT = 0mA Output Voltage (V) 2.8 2.6 2.4 2.2 2.0 2.7 IL = 150mA IL = 100mA IOUT = 300mA IOUT = 150mA IOUT = 100mA IOUT = 50mA IL = 50mA -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 IOUT = 10mA 2.8 2.9 3.0 3.1 3.2 3.3 Temperature (C) Input Voltage (V) Dropout Voltage vs. Output Current 500 90 80 Ground Current vs. Input Voltage Dropout Voltage (mV) Ground Current (A) 450 400 350 300 250 200 150 100 50 0 0 50 100 150 200 250 300 70 60 50 40 30 20 10 0 2 2.5 3 3.5 4 4.5 5 85C 25C -40C IOUT = 300mA IOUT = 0mA IOUT = 150mA IOUT = 50mA IOUT = 10mA Output Current (mA) Input Voltage (V) Quiescent Current vs. Temperature 100 Output Voltage vs. Temperature 1.203 1.202 Quiescent Current (A) 90 Output Voltage (V) -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 80 70 60 50 40 30 20 10 0 1.201 1.200 1.199 1.198 1.197 1.196 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 Temperature (C) Temperature (C) 2554.2007.01.1.2 13 Total Power Solution for Portable Applications Typical Characteristics - LDO Regulator LDO Initial Power-Up Response Time 7 6 5 4 3 2 1 0 AAT2554 LDO Turn-On Time from Enable (VIN Present) 6 4 3 2 1 0 Output Voltage (bottom) (V) Output Voltage (bottom) (V) Enable Voltage (top) (V) Input Voltage (top) (V) 6 5 4 3 2 1 0 5 4 3 2 1 0 Time (50s/div) Time (5s/div) Turn-Off Response Time (I = 100mA) 6 Line Transient Response 3.04 3.03 3.02 3.01 3.00 VEN (5V/div) Input Voltage (V) 5 4 3 2 Output Voltage (V) VIN VOUT 1 0 2.99 2.98 VOUT (1V/div) Time (50s/div) Time (100s/div) Load Transient Response 2.90 500 Load Transient Response 300mA 3.0 800 700 Output Voltage (V) Output Voltage (V) 2.85 2.80 2.75 2.70 2.65 VOUT 400 300 200 100 0 Output Current (mA) 2.9 2.8 2.7 2.6 2.5 2.4 2.3 2.2 2.1 Output Current (mA) VOUT 600 500 400 300 200 IOUT 2.60 -100 IOUT 100 0 -100 Time (100s/div) Time (10s/div) 14 2554.2007.01.1.2 Total Power Solution for Portable Applications Typical Characteristics - LDO Regulator Over-Current Protection (EN = GND; ENLDO = VIN) 1200 AAT2554 VEN(L) and VEN(H) vs. VIN Enable Threshold Voltage (V) 1.250 1.225 1.200 1.175 1.150 1.125 1.100 1.075 1.050 2.5 3.0 3.5 4.0 4.5 5.0 5.5 Output Current (mA) 1000 800 600 400 200 0 -200 VEN(H) VEN(L) Time (50ms/div) Input Voltage (V) 2554.2007.01.1.2 15 Total Power Solution for Portable Applications Functional Block Diagram Reverse Blocking AAT2554 ADP - BAT + STAT OverTemperature Protection UVLO VINA Err. Amp. Logic VREF DL OverCurrent Protection + OUTA ENA GND Functional Description The AAT2554 is a high performance power management IC comprised of a lithium-ion/polymer battery charger, a step-down converter, and a linear regulator. The linear regulator is designed for high-speed turn-on and fast transient response, and good power supply ripple rejection. The stepdown converter operates in both fixed and variable frequency modes for high efficiency performance. The switching frequency is 1.5MHz, minimizing the size of the inductor. In light load conditions, the device enters power-saving mode; the switching frequency is reduced and the converter consumes 30A of current, making it ideal for batteryoperated applications. Battery Charger The battery charger is designed for single-cell lithium-ion/polymer batteries using a constant current and constant voltage algorithm. The battery charger operates from the adapter/USB input voltage range from 4V to 6.5V. The adapter/USB charging current level can be programmed up to 500mA for rapid charging applications. A status monitor output pin is provided to indicate the battery charge state by directly driving one external LED. Internal device temperature and charging state are fully monitored for fault conditions. In the event of an over-voltage or over-temperature failure, the device will automatically shut down, protecting the charging device, control system, and the battery under charge. Other features include an integrated reverse blocking diode and sense resistor. 16 + ISET VREF Constant Current Charge Control EN_BAT VINB DH LX ENB FB VREF 2554.2007.01.1.2 Total Power Solution for Portable Applications Switch-Mode Step-Down Converter The step-down converter operates with an input voltage of 2.7V to 5.5V. The switching frequency is 1.5MHz, minimizing the size of the inductor. Under light load conditions, the device enters power-saving mode; the switching frequency is reduced, and the converter consumes 30A of current, making it ideal for battery-operated applications. The output voltage is programmable from VIN to as low as 0.6V. Power devices are sized for 250mA current capability while maintaining over 90% efficiency at full load. Light load efficiency is maintained at greater than 80% down to 1mA of load current. A high-DC gain error amplifier with internal compensation controls the output. It provides excellent transient response and load/line regulation. AAT2554 Under-Voltage Lockout The AAT2554 has internal circuits for UVLO and power on reset features. If the ADP supply voltage drops below the UVLO threshold, the battery charger will suspend charging and shut down. When power is reapplied to the ADP pin or the UVLO condition recovers, the system charge control will automatically resume charging in the appropriate mode for the condition of the battery. If the input voltage of the step-down converter drops below UVLO, the internal circuit will shut down. Protection Circuitry Over-Voltage Protection An over-voltage protection event is defined as a condition where the voltage on the BAT pin exceeds the over-voltage protection threshold (VOVP). If this over-voltage condition occurs, the charger control circuitry will shut down the device. The charger will resume normal charging operation after the over-voltage condition is removed. Current Limit, Over-Temperature Protection For overload conditions, the peak input current is limited at the step-down converter. As load impedance decreases and the output voltage falls closer to zero, more power is dissipated internally, which causes the internal die temperature to rise. In this case, the thermal protection circuit completely disables switching, which protects the device from damage. The battery charger has a thermal protection circuit which will shut down charging functions when the internal die temperature exceeds the preset thermal limit threshold. Once the internal die temperature falls below the thermal limit, normal charging operation will resume. Linear Regulator The advanced circuit design of the linear regulator has been specifically optimized for very fast startup. This proprietary CMOS LDO has also been tailored for superior transient response characteristics. These traits are particularly important for applications that require fast power supply timing. The high-speed turn-on capability is enabled through implementation of a fast-start control circuit which accelerates the power-up behavior of fundamental control and feedback circuits within the LDO regulator. The LDO regulator output has been specifically optimized to function with lowcost, low-ESR ceramic capacitors; however, the design will allow for operation over a wide range of capacitor types. The regulator comes with complete short-circuit and thermal protection. The combination of these two internal protection circuits gives a comprehensive safety system to guard against extreme adverse operating conditions. The regulator features an enable/disable function. This pin (ENA) is active high and is compatible with CMOS logic. To assure the LDO regulator will switch on, the ENA turn-on control level must be greater than 1.5V. The LDO regulator will go into the disable shutdown mode when the voltage on the ENA pin falls below 0.6V. If the enable function is not needed in a specific application, it may be tied to VINA to keep the LDO regulator in a continuously on state. Control Loop The AAT2554 contains a compact, current mode step-down DC/DC controller. The current through the P-channel MOSFET (high side) is sensed for current loop control, as well as short-circuit and overload protection. A fixed slope compensation signal is added to the sensed current to maintain stability for duty cycles greater than 50%. The peak current mode loop appears as a voltage-programmed current source in parallel with the output capacitor. The output of the voltage error amplifier 2554.2007.01.1.2 17 Total Power Solution for Portable Applications programs the current mode loop for the necessary peak switch current to force a constant output voltage for all load and line conditions. Internal loop compensation terminates the transconductance voltage error amplifier output. The error amplifier reference is fixed at 0.6V. charger begins constant-current charging. The current level for this mode is programmed using a single resistor from the ISET pin to ground. Programmed current can be set from a minimum 15mA up to a maximum of 500mA. Constant current charging will continue until the battery voltage reaches the voltage regulation point, VBAT. When the battery voltage reaches VBAT, the battery charger begins constant voltage mode. The regulation voltage is factory programmed to a nominal 4.2V (0.5%) and will continue charging until the charging current has reduced to 10% of the programmed current. After the charge cycle is complete, the pass device turns off and the device automatically goes into a power-saving sleep mode. During this time, the series pass device will block current in both directions, preventing the battery from discharging through the IC. The battery charger will remain in sleep mode, even if the charger source is disconnected, until one of the following events occurs: the battery terminal voltage drops below the VRCH threshold; the charger EN pin is recycled; or the charging source is reconnected. In all cases, the charger will monitor all parameters and resume charging in the most appropriate mode. AAT2554 Battery Charging Operation Battery charging commences only after checking several conditions in order to maintain a safe charging environment. The input supply (ADP) must be above the minimum operating voltage (UVLO) and the enable pin must be high (internally pulled down). When the battery is connected to the BAT pin, the charger checks the condition of the battery and determines which charging mode to apply. If the battery voltage is below VMIN, the charger begins battery pre-conditioning by charging at 10% of the programmed constant current; e.g., if the programmed current is 150mA, then the pre-conditioning current (trickle charge) is 15mA. Pre-conditioning is purely a safety precaution for a deeply discharged cell and will also reduce the power dissipation in the internal series pass MOSFET when the input-output voltage differential is at its highest. Pre-conditioning continues until the battery voltage reaches VMIN (see Figure 1). At this point, the Charge Complete Voltage Regulated Current Preconditioning Trickle Charge Phase Constant Current Charge Phase I = Max CC Constant Voltage Charge Phase Constant Current Mode Voltage Threshold Trickle Charge and Termination Threshold I = CC / 10 Figure 1: Current vs. Voltage Profile During Charging Phases. 18 2554.2007.01.1.2 Total Power Solution for Portable Applications Battery Charging System Operation Flow Chart AAT2554 Enable Power On Reset No Yes Power Input Voltage VADP > VUVLO Yes Shut Down Yes Fault Conditions Monitoring OV, OT Charge Control No Preconditioning Test V MIN > VBAT Yes Preconditioning (Trickle Charge) No No Recharge Test V RCH > VBAT Yes Current Phase Test V ADP > VBAT Yes Constant Current Charge Mode No Voltage Phase Test IBAT > ITERM Yes Constant Voltage Charge Mode No Charge Completed 2554.2007.01.1.2 19 Total Power Solution for Portable Applications Application Information Soft Start / Enable The EN_BAT pin is internally pulled down. When pulled to a logic high level, the battery charger is enabled. When left open or pulled to a logic low level, the battery charger is shut down and forced into the sleep state. Charging will be halted regardless of the battery voltage or charging state. When it is reenabled, the charge control circuit will automatically reset and resume charging functions with the appropriate charging mode based on the battery charge state and measured cell voltage from the BAT pin. Separate ENA and ENB inputs are provided to independently enable and disable the LDO and step-down converter, respectively. This allows sequencing of the LDO and step-down outputs during startup. The LDO is enabled when the ENA pin is pulled high. The control and feedback circuits have been optimized for high-speed, monotonic turn-on characteristics. The step-down converter is enabled when the ENB pin is pulled high. Soft start increases the inductor current limit point in discrete steps when the input voltage or ENB input is applied. It limits the current surge seen at the input and eliminates output voltage overshoot. When pulled low, the ENB input forces the AAT2554 into a low-power, non-switching state. The total input current during shutdown is less than 1A. le charge current, is dominated by the tolerance of the set resistor used. For this reason, a 1% tolerance metal film resistor is recommended for the set resistor function. Fast charge constant current levels from 15mA to 500mA may be set by selecting the appropriate resistor value from Table 1. Normal ICHARGE (mA) 500 400 300 250 200 150 100 50 40 30 20 15 AAT2554 Set Resistor Value R1 (k) 3.24 4.12 5.36 6.49 8.06 10.7 16.2 31.6 38.3 53.6 78.7 105 Table 1: RSET Values. 1000 ICH (mA) 100 10 Adapter or USB Power Input Constant current charge levels up to 500mA may be programmed by the user when powered from a sufficient input power source. The battery charger will operate from the adapter input over a 4.0V to 6.5V range. The constant current fast charge current for the adapter input is set by the RSET resistor connected between ISET and ground. Refer to Table 1 for recommended RSET values for a desired constant current charge level. 1 1 10 100 1000 RSET (k) Figure 2: Constant Charging Current vs. Set Resistor Values. Charge Status Output The AAT2554 provides battery charge status via a status pin. This pin is internally connected to an Nchannel open drain MOSFET, which can be used to drive an external LED. The status pin can indicate several conditions, as shown in Table 2. Programming Charge Current The fast charge constant current charge level is user programmed with a set resistor placed between the ISET pin and ground. The accuracy of the fast charge, as well as the preconditioning trick20 2554.2007.01.1.2 Total Power Solution for Portable Applications Event Description No battery charging activity Battery charging via adapter or USB port Charging completed AAT2554 Status OFF ON OFF First, the maximum power dissipation for a given situation should be calculated: PD(MAX) = Where: (TJ(MAX) - TA) JA Table 2: LED Status Indicator. The LED should be biased with as little current as necessary to create reasonable illumination; therefore, a ballast resistor should be placed between the LED cathode and the STAT pin. LED current consumption will add to the overall thermal power budget for the device package, hence it is good to keep the LED drive current to a minimum. 2mA should be sufficient to drive most low-cost green or red LEDs. It is not recommended to exceed 8mA for driving an individual status LED. The required ballast resistor values can be estimated using the following formulas: PD(MAX) = Maximum Power Dissipation (W) JA = Package Thermal Resistance (C/W) TJ(MAX) = Maximum Device Junction Temperature (C) [135C] TA = Ambient Temperature (C) Figure 3 shows the relationship of maximum power dissipation and ambient temperature of the AAT2554. 3000 2500 PD(MAX) (mW) 2000 1500 1000 500 0 0 20 40 60 80 100 120 (VADP - VF(LED)) R 1= ILED Example: R1 = (5.5V - 2.0V) = 1.75k 2mA TA (C) Figure 3: Maximum Power Dissipation. Next, the power dissipation of the battery charger can be calculated by the following equation: Note: Red LED forward voltage (VF) is typically 2.0V @ 2mA. Thermal Considerations The AAT2554 is offered in a TDFN34-16 package which can provide up to 2W of power dissipation when it is properly bonded to a printed circuit board and has a maximum thermal resistance of 50C/W. Many considerations should be taken into account when designing the printed circuit board layout, as well as the placement of the charger IC package in proximity to other heat generating devices in a given application design. The ambient temperature around the IC will also have an effect on the thermal limits of a battery charging application. The maximum limits that can be expected for a given ambient condition can be estimated by the following discussion. Where: PD PD = [(VADP - VBAT) * ICH + (VADP * IOP)] = Total Power Dissipation by the Device VADP = ADP/USB Voltage VBAT = Battery Voltage as Seen at the BAT Pin ICH IOP = Constant Charge Current Programmed for the Application = Quiescent Current Consumed by the Charger IC for Normal Operation [0.5mA] 2554.2007.01.1.2 21 Total Power Solution for Portable Applications By substitution, we can derive the maximum charge current before reaching the thermal limit condition (thermal cycling). The maximum charge current is the key factor when designing battery charger applications. IQ is the step-down converter quiescent current. The term tsw is used to estimate the full load stepdown converter switching losses. For the condition where the step-down converter is in dropout at 100% duty cycle, the total device dissipation reduces to: PTOTAL = IO2 * RDSON(H) + IQ * VIN AAT2554 ICH(MAX) = (PD(MAX) - VIN * IOP) VIN - VBAT (TJ(MAX) - TA) - V * I IN OP JA ICH(MAX) = VIN - VBAT In general, the worst condition is the greatest voltage drop across the IC, when battery voltage is charged up to the preconditioning voltage threshold. Figure 4 shows the maximum charge current in different ambient temperatures. 500 400 Since RDS(ON), quiescent current, and switching losses all vary with input voltage, the total losses should be investigated over the complete input voltage range. Given the total losses, the maximum junction temperature can be derived from the JA for the TDFN34-16 package which is 50C/W. TJ(MAX) = PTOTAL * JA + TAMB ICC(MAX) (mA) TA = 60C 300 Capacitor Selection TA = 85C 200 100 0 4.25 4.5 4.75 5 5.25 5.5 5.75 6 6.25 6.5 6.75 VIN (V) Figure 4: Maximum Charging Current Before Thermal Cycling Becomes Active. There are three types of losses associated with the step-down converter: switching losses, conduction losses, and quiescent current losses. Conduction losses are associated with the RDS(ON) characteristics of the power output switching devices. Switching losses are dominated by the gate charge of the power output switching devices. At full load, assuming continuous conduction mode (CCM), a simplified form of the losses is given by: IO2 * (RDSON(H) * VO + RDSON(L) * [VIN - VO]) VIN Linear Regulator Input Capacitor (C7) An input capacitor greater than 1F will offer superior input line transient response and maximize power supply ripple rejection. Ceramic, tantalum, or aluminum electrolytic capacitors may be selected for CIN. There is no specific capacitor ESR requirement for CIN. However, for 300mA LDO regulator output operation, ceramic capacitors are recommended for CIN due to their inherent capability over tantalum capacitors to withstand input current surges from low impedance sources such as batteries in portable devices. Battery Charger Input Capacitor (C3) In general, it is good design practice to place a decoupling capacitor between the ADP pin and GND. An input capacitor in the range of 1F to 22F is recommended. If the source supply is unregulated, it may be necessary to increase the capacitance to keep the input voltage above the under-voltage lockout threshold during device enable and when battery charging is initiated. If the adapter input is to be used in a system with an external power supply source, such as a typical AC-to-DC wall adapter, then a CIN capacitor in the range of 10F should be used. A larger input PTOTAL = + (tsw * FS * IO + IQ) * VIN 22 2554.2007.01.1.2 Total Power Solution for Portable Applications capacitor in this application will minimize switching or power transient effects when the power supply is "hot plugged" in. Step-Down Converter Input Capacitor (C1) Select a 4.7F to 10F X7R or X5R ceramic capacitor for the input. To estimate the required input capacitor size, determine the acceptable input ripple level (VPP) and solve for CIN. The calculated value varies with input voltage and is a maximum when VIN is double the output voltage. VO AAT2554 IRMS(MAX) = V * 1- O IO 2 The term VIN VIN appears in both the input voltage ripple and input capacitor RMS current equations and is a maximum when VO is twice VIN. This is why the input voltage ripple and the input capacitor RMS current ripple are a maximum at 50% duty cycle. The input capacitor provides a low impedance loop for the edges of pulsed current drawn by the stepdown converter. Low ESR/ESL X7R and X5R ceramic capacitors are ideal for this function. To minimize stray inductance, the capacitor should be placed as closely as possible to the IC. This keeps the high frequency content of the input current localized, minimizing EMI and input voltage ripple. The proper placement of the input capacitor (C1) can be seen in the evaluation board layout in Figure 6. A laboratory test set-up typically consists of two long wires running from the bench power supply to the evaluation board input voltage pins. The inductance of these wires, along with the low-ESR ceramic input capacitor, can create a high Q network that may affect converter performance. This problem often becomes apparent in the form of excessive ringing in the output voltage during load transients. Errors in the loop phase and gain measurements can also result. Since the inductance of a short PCB trace feeding the input voltage is significantly lower than the power leads from the bench power supply, most applications do not exhibit this problem. In applications where the input power source lead inductance cannot be reduced to a level that does not affect the converter performance, a high ESR tantalum or aluminum electrolytic capacitor should be placed in parallel with the low ESR, ESL bypass ceramic capacitor. This dampens the high Q network and stabilizes the system. Linear Regulator Output Capacitor (C6) For proper load voltage regulation and operational stability, a capacitor is required between OUT and GND. The COUT capacitor connection to the LDO CIN = VO V * 1- O VIN VIN VPP - ESR * FS IO VO V 1 * 1 - O = for VIN = 2 * VO VIN VIN 4 CIN(MIN) = 1 VPP - ESR * 4 * FS IO Always examine the ceramic capacitor DC voltage coefficient characteristics when selecting the proper value. For example, the capacitance of a 10F, 6.3V, X5R ceramic capacitor with 5.0V DC applied is actually about 6F. The maximum input capacitor RMS current is: IRMS = IO * VO V * 1- O VIN VIN The input capacitor RMS ripple current varies with the input and output voltage and will always be less than or equal to half of the total DC load current. VO V * 1- O = VIN VIN for VIN = 2 * VO D * (1 - D) = 0.52 = 1 2 2554.2007.01.1.2 23 Total Power Solution for Portable Applications regulator ground pin should be made as directly as practically possible for maximum device performance. Since the regulator has been designed to function with very low ESR capacitors, ceramic capacitors in the 1.0F to 10F range are recommended for best performance. Applications utilizing the exceptionally low output noise and optimum power supply ripple rejection should use 2.2F or greater for COUT. In low output current applications, where output load is less than 10mA, the minimum value for COUT can be as low as 0.47F. Battery Charger Output Capacitor (C5) The AAT2554 only requires a 1F ceramic capacitor on the BAT pin to maintain circuit stability. This value should be increased to 10F or more if the battery connection is made any distance from the charger output. If the AAT2554 is to be used in applications where the battery can be removed from the charger, such as with desktop charging cradles, an output capacitor greater than 10F may be required to prevent the device from cycling on and off when no battery is present. Step-Down Converter Output Capacitor (C4) The output capacitor limits the output ripple and provides holdup during large load transitions. A 4.7F to 10F X5R or X7R ceramic capacitor typically provides sufficient bulk capacitance to stabilize the output during large load transitions and has the ESR and ESL characteristics necessary for low output ripple. For enhanced transient response and low temperature operation applications, a 10F (X5R, X7R) ceramic capacitor is recommended to stabilize extreme pulsed load conditions. The output voltage droop due to a load transient is dominated by the capacitance of the ceramic output capacitor. During a step increase in load current, the ceramic output capacitor alone supplies the load current until the loop responds. Within two or three switching cycles, the loop responds and the inductor current increases to match the load current demand. The relationship of the output voltage droop during the three switching cycles to the output capacitance can be estimated by: 3 * ILOAD VDROOP * FS AAT2554 Once the average inductor current increases to the DC load level, the output voltage recovers. The above equation establishes a limit on the minimum value for the output capacitor with respect to load transients. The internal voltage loop compensation also limits the minimum output capacitor value to 4.7F. This is due to its effect on the loop crossover frequency (bandwidth), phase margin, and gain margin. Increased output capacitance will reduce the crossover frequency with greater phase margin. The maximum output capacitor RMS ripple current is given by: VOUT * (VIN(MAX) - VOUT) L * FS * VIN(MAX) 2* 3 * 1 IRMS(MAX) = Dissipation due to the RMS current in the ceramic output capacitor ESR is typically minimal, resulting in less than a few degrees rise in hotspot temperature. Inductor Selection The step-down converter uses peak current mode control with slope compensation to maintain stability for duty cycles greater than 50%. The output inductor value must be selected so the inductor current down slope meets the internal slope compensation requirements. The internal slope compensation for the AAT2554 is 0.45A/sec. This equates to a slope compensation that is 75% of the inductor current down slope for a 1.8V output and 3.0H inductor. m= 0.75 VO 0.75 1.8V A = = 0.45 L 3.0H sec L= 0.75 VO = m 0.75 VO sec 1.67 A VO A 0.45A sec COUT = 24 2554.2007.01.1.2 Total Power Solution for Portable Applications For most designs, the step-down converter operates with inductor values from 1H to 4.7H. Table 3 displays inductor values for the AAT2554 for various output voltages. Manufacturer's specifications list both the inductor DC current rating, which is a thermal limitation, and the peak current rating, which is determined by the saturation characteristics. The inductor should not show any appreciable saturation under normal load conditions. Some inductors may meet the peak and average current ratings yet result in excessive losses due to a high DCR. Always consider the losses associated with the DCR and its effect on the total converter efficiency when selecting an inductor. The 3.0H CDRH2D09 series inductor selected from Sumida has a 150m DCR and a 470mA DC current rating. At full load, the inductor DC loss is 9.375mW which gives a 2.08% loss in efficiency for a 250mA, 1.8V output. Output Voltage (V) 1.0 1.2 1.5 1.8 2.5 3.0 3.3 AAT2554 Adjustable Output Resistor Selection Resistors R2 and R3 of Figure 5 program the output to regulate at a voltage higher than 0.6V. To limit the bias current required for the external feedback resistor string while maintaining good noise immunity, the suggested value for R3 is 59k. Decreased resistor values are necessary to maintain noise immunity on the FB pin, resulting in increased quiescent current. Table 4 summarizes the resistor values for various output voltages. VOUT 3.3V R2 = V -1 * R3 = 0.6V - 1 * 59k = 267k REF With enhanced transient response for extreme pulsed load application, an external feed-forward capacitor (C8 in Figure 5) can be added. R3 = 59k VOUT (V) 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.8 1.85 2.0 2.5 3.3 R3 = 221k R2 (k) 75 113 150 187 221 261 301 332 442 464 523 715 1000 L1 (H) 1.5 2.2 2.7 3.0/3.3 3.9/4.2 4.7 5.6 R2 (k) 19.6 29.4 39.2 49.9 59.0 68.1 78.7 88.7 118 124 137 187 267 Table 3: Step-Down Converter Inductor Values. Table 4: Adjustable Resistor Values For Step-Down Converter. 2554.2007.01.1.2 25 Total Power Solution for Portable Applications VINB VINB C1 4.7F U1 ADP ADP C3 4.7F D1 R5 100K JP2 R6 100K JP3 3 2 1 6 3 2 1 7 16 11 9 4 AAT2554 VBAT BAT OUTA LX FB GND GND 8 5 15 1 14 12 10 2 1 VINB ADP STAT VINA ENA ENB R4 1K VOUTA L1 2 VOUTB VOUTB VOUTA ENA 13 3 VINA C7 2.2F ADP VINB R2 118K FB R3 59K C8 100pF C8 optional for enhanced stepdown converter transient response C4 4.7F C6 2.2F C5 2.2F EN_BAT GND ISET AAT2554 GND R7 100K JP1 3 2 1 ENB ENA ENB R1 8.06K EN_BAT GND EN_BAT Figure 5: AAT2554 Evaluation Board Schematic. Printed Circuit Board Layout Considerations For the best results, it is recommended to physically place the battery pack as close as possible to the AAT2554 BAT pin. To minimize voltage drops on the PCB, keep the high current carrying traces adequately wide. Refer to the AAT2554 evaluation board for a good layout example (see Figures 6 and 7). The following guidelines should be used to help ensure a proper layout. 1. The input capacitors (C1, C3, C7) should connect as closely as possible to ADP (Pin 11), VINA (Pin 4), and VINB (Pin 16). 2. C4 and L1 should be connected as closely as possible. The connection of L1 to the LX pin should be as short as possible. Do not make the node small by using narrow trace. The trace should be kept wide, direct, and short. 3. The feedback pin (Pin 1) should be separate from any power trace and connect as closely as possible to the load point. Sensing along a highcurrent load trace will degrade DC load regulation. Feedback resistors should be placed as closely as possible to the FB pin (Pin 1) to minimize the length of the high impedance feedback trace. If possible, they should also be placed away from the LX (switching node) and inductor to improve noise immunity. 4. The resistance of the trace from the load return GND (Pins 2, 10, 12, and 14) should be kept to a minimum. This will help to minimize any error in DC regulation due to differences in the potential of the internal signal ground and the power ground. 5. A high density, small footprint layout can be achieved using an inexpensive, miniature, nonshielded, high DCR inductor. 26 2554.2007.01.1.2 Total Power Solution for Portable Applications AAT2554 Figure 6: AAT2554 Evaluation Board Top Side Layout. Figure 7: AAT2554 Evaluation Board Bottom Side Layout. Component U1 C1, C3, C4 C5, C6, C7 C8 L1 R4 R1 R2 R3 R5, R6, R7 JP1, JP2, JP3 D1 Part Number AAT2554IRN-T1 GRM188R60J475KE19 GRM188R61A225KE34 GRM1886R1H101JZ01J CDRH2D09-3R0 Chip Resistor Chip Resistor Chip Resistor Chip Resistor Chip Resistor PRPN401PAEN CMD15-21SRC/TR8 Description Total Power Solution for Portable Applications CER 4.7F 6.3V X5R 0603 CER 2.2F 10V X5R 0603 CER 100pF 50V 5% R2H 0603 Shielded SMD, 3.0H, 150m, 3x3x1mm 1k, 5%, 1/4W; 0603 8.06k, 1%, 1/4W; 0603 118k, 1%, 1/4W; 0603 59k, 1%, 1/4W; 0603 100k, 5%, 1/8W; 0402 Connecting Header, 2mm zip Red LED; 1206 Manufacturer AnalogicTech Murata Murata Murata Sumida Vishay Vishay Vishay Vishay Vishay Sullins Electronics Chicago Miniature Lamp Table 5: AAT2554 Evaluation Board Component Listing. 2554.2007.01.1.2 27 Total Power Solution for Portable Applications Step-Down Converter Design Example Specifications VO VIN FS TAMB = 1.8V @ 250mA, Pulsed Load ILOAD = 200mA = 2.7V to 4.2V (3.6V nominal) = 1.5MHz = 85C AAT2554 1.8V Output Inductor L1 = 1.67 sec sec VO2 = 1.67 1.8V = 3H A A (use 3.0H; see Table 3) For Sumida inductor CDRH2D09-3R0, 3.0H, DCR = 150m. VO V 1.8V 1.8V 1- O = 1 = 228mA L1 FS VIN 3.0H 1.5MHz 4.2V IL1 = IPKL1 = IO + IL1 = 250mA + 114mA = 364mA 2 PL1 = IO2 DCR = 250mA2 150m = 9.375mW 1.8V Output Capacitor VDROOP = 0.1V 3 * ILOAD 3 * 0.2A = = 4F (use 4.7F) 0.1V * 1.5MHz VDROOP * FS 1 2* 3 * (VO) * (VIN(MAX) - VO) 1 1.8V * (4.2V - 1.8V) * = 66mArms = L1 * FS * VIN(MAX) 2 * 3 3.0H * 1.5MHz * 4.2V COUT = IRMS = Pesr = esr * IRMS2 = 5m * (66mA)2 = 21.8W 28 2554.2007.01.1.2 Total Power Solution for Portable Applications Input Capacitor Input Ripple VPP = 25mV AAT2554 CIN = 1 VPP - ESR * 4 * FS IO = 1 = 1.38F (use 4.7F) 25mV - 5m * 4 * 1.5MHz 0.2A IRMS = IO = 0.1Arms 2 P = esr * IRMS2 = 5m * (0.1A)2 = 0.05mW AAT2554 Losses IO2 * (RDSON(H) * VO + RDSON(L) * [VIN -VO]) VIN PTOTAL = + (tsw * FS * IO + IQ) * VIN = 0.22 * (0.59 * 1.8V + 0.42 * [4.2V - 1.8V]) 4.2V + (5ns * 1.5MHz * 0.2A + 30A) * 4.2V = 26.14mW TJ(MAX) = TAMB + JA * PLOSS = 85C + (50C/W) * 26.14mW = 86.3C 2554.2007.01.1.2 29 Total Power Solution for Portable Applications Output Voltage VOUT (V) 0.6 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.8 1.85 2.0 2.5 3.3 AAT2554 R3 = 59k R2 (k) 0 19.6 29.4 39.2 49.9 59.0 68.1 78.7 88.7 118 124 137 187 267 R3 = 221k1 R2 (k) 0 75 113 150 187 221 261 301 332 442 464 523 715 1000 L1 (H) 1.5 1.5 1.5 1.5 1.5 1.5 1.5 2.2 2.7 3.0/3.3 3.0/3.3 3.0/3.3 3.9/4.2 5.6 Table 6: Step-Down Converter Component Values. Manufacturer Sumida Sumida Sumida Sumida Sumida Sumida Sumida Sumida Sumida Sumida Sumida Taiyo Yuden Taiyo Yuden Taiyo Yuden Taiyo Yuden FDK FDK FDK FDK Part Number CDRH2D09-1R5 CDRH2D09-2R2 CDRH2D09-2R5 CDRH2D09-3R0 CDRH2D09-3R9 CDRH2D09-4R7 CDRH2D09-5R6 CDRH2D11-1R5 CDRH2D11-2R2 CDRH2D11-3R3 CDRH2D11-4R7 NR3010T1R5N NR3010T2R2M NR3010T3R3M NR3010T4R7M MIPWT3226D-1R5 MIPWT3226D-2R2 MIPWT3226D-3R0 MIPWT3226D-4R2 Inductance (H) 1.5 2.2 2.5 3.0 3.9 4.7 5.6 1.5 2.2 3.3 4.7 1.5 2.2 3.3 4.7 1.5 2.2 3.0 4.2 Max DC Current (mA) 730 600 530 470 450 410 370 900 780 600 500 1200 1100 870 750 1200 1100 1000 900 DCR (m) 110 144 150 194 225 287 325 68 98 123 170 80 95 140 190 90 100 120 140 Size (mm) LxWxH 3.0x3.0x1.0 3.0x3.0x1.0 3.0x3.0x1.0 3.0x3.0x1.0 3.0x3.0x1.0 3.0x3.0x1.0 3.0x3.0x1.0 3.2x3.2x1.2 3.2x3.2x1.2 3.2x3.2x1.2 3.2x3.2x1.2 3.0x3.0x1.0 3.0x3.0x1.0 3.0x3.0x1.0 3.0x3.0x1.0 3.2x2.6x0.8 3.2x2.6x0.8 3.2x2.6x0.8 3.2x2.6x0.8 Type Shielded Shielded Shielded Shielded Shielded Shielded Shielded Shielded Shielded Shielded Shielded Shielded Shielded Shielded Shielded Chip shielded Chip shielded Chip shielded Chip shielded Table 7: Suggested Inductors and Suppliers. 1. For reduced quiescent current, R3 = 221k. 30 2554.2007.01.1.2 Total Power Solution for Portable Applications Value (F) 10 4.7 2.2 2.2 1.0 1.0 AAT2554 Manufacturer Murata Murata Murata Murata Murata Murata Part Number GRM21BR61A106KE19 GRM188R60J475KE19 GRM188R61A225KE34 GRM188R60J225KE19 GRM188R61A105KA61 GRM185R60J105KE26 Voltage Rating 10 6.3 10 6.3 10 6.3 Temp. Co. X5R X5R X5R X5R X5R X5R Case Size 0805 0603 0603 0603 0603 0603 Table 8: Surface Mount Capacitors. 2554.2007.01.1.2 31 Total Power Solution for Portable Applications Ordering Information Package TDFN34-16 TDFN34-16 TDFN34-16 TDFN34-16 AAT2554 Marking1 RZXYY VHXYY SAXYY TOXYY Part Number (Tape and Reel)2 AAT2554IRN-CAP-T1 AAT2554IRN-CAQ-T1 AAT2554IRN-CAT-T1 AAT2554IRN-CAW-T1 All AnalogicTech products are offered in Pb-free packaging. The term "Pb-free" means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/pbfree. Legend Voltage Adjustable (0.6V) 0.9 1.2 1.5 1.8 1.9 2.5 2.6 2.7 2.8 2.85 2.9 3.0 3.3 4.2 Code A B E G I Y N O P Q R S T W C 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. 32 2554.2007.01.1.2 Total Power Solution for Portable Applications Package Information1 TDFN34-16 3.00 0.05 Detail "A" AAT2554 Index Area 4.00 0.05 0.35 0.10 Top View Bottom View 0.23 0.05 (4x) 0.85 MAX Pin 1 Indicator (optional) 0.45 0.05 0.05 0.05 0.229 0.051 Side View Detail "A" All dimensions in millimeters. 1. The leadless package family, which includes QFN, TQFN, DFN, TDFN and STDFN, has exposed copper (unplated) at the end of the lead terminals due to the manufacturing process. A solder fillet at the exposed copper edge cannot be guaranteed and is not required to ensure a proper bottom solder connection. (c) Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech's standard warranty. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders. Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737- 4600 Fax (408) 737- 4611 2554.2007.01.1.2 33 |
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