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| ATH22T05 Series --5-V Input 22-A, 5-V Input Non-Isolated Wide-Output Adjust Power Module REVISION 00 (3DEC2003) Features * Up to 22 A Output Current * 5-V Input Voltage * Wide-Output Voltage Adjust (0.8 V to 3.6 V) * Efficiencies up to 96 % * 155 W/in Power Density * On/Off Inhibit * Output Voltage Sense * Pre-Bias Startup * Margin Up/Down Controls * Auto-TrackTM Sequencing * Under-Voltage Lockout * Output Over-Current Protection (Non-Latching, Auto-Reset) * Over-T emperature Protection * Surface Mountable * Operating Temp: -40 to +85 C * DSP Compatible Output Voltages * IPC Lead Free 2 * Point-of-Load Alliance (POLA) Compatible NOMINAL SIZE = 1.5 in x 0.87 in (38,1 mm x 22,1 mm) Description The ATH22T05 series of non-isolated power modules offers OEM designers a combination of high performance, small footprint, and industry leading features. As part of a new class of power modules these products provide designers with the flexibility to power the most complex multi-processor digital systems using off-the-shelf catalog parts. The series employs double-sided surface mount construction and provides highperformance step-down power conversion for up to 22 A of output current from a 5-V input bus voltage. The output voltage of the ATH22T05 can be set to any value over the range, 0.8 V to 3.6 V, using a single resistor. This series includes Auto-TrackTM. Auto-Track simplifies the task of supply voltage sequencing in a power system by enabling modules to track each other, or any external voltage, during power up and power down. Other operating features include an on/off inhibit, output voltage adjust (trim), and margin up/down controls. To ensure tight load regulation, an output voltage sense is also provided. A non-latching over-current trip and over-temperature shutdown provides load fault protection. Target applications include complex multi-voltage, multi-processor systems that incorporate the industry's high-speed DSPs, micro-processors and bus drivers. Pin Configuration Pin 1 2 3 4 5 6 7 8 9 10 Function GND Vin Inhibit * Vo Adjust Vo Sense Vout GND Track Margin Down * Margin Up * * Denotes negative logic: Open = Normal operation Ground = Function active TM Track Auto- ncing e Sequ Standard Application Track Margin Down Margin Up 10 1 9 8 7 Rset = Resistor to set the desired output voltage (see spec. table for values). Cin = Required electrolytic 1,000 F Cout = Optional 330 F electrolytic ATH22T05-9S PTH05020W VIN (Top View) 2 6 VOUT 3 4 5 Inhibit Vo Sense L O A D GND North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 + CIN 1,000 F (Required) RSET (Required) 0.1 W, 1 % COUT 330 F (Optional) GND + Asia (HK): 852-2437-9662 ATH22T05 Series --5-V Input 22-A, 5-V Input Non-Isolated Wide-Output Adjust Power Module REVISION 00 (3DEC2003) Ordering Information Input Voltage 4.5V to 5.5V Options: "-J" "-SJ" "-S" - Output Voltage 0.8V1 to 3.6V Output Current 22A Model Number ATH22T05-9(S)(J) Through-hole Termination, Tray Packaging SMT Termination, Tray Packaging SMT Termination, T&R Packaging Notes: 1 Preset output voltage is 0.8V; externally adjustable to 3.6V through the Vo,Adjust pin Pin Descriptions Vin: The positive input voltage power node to the module, which is referenced to common GND. Vout: The regulated positive power output with respect to the GND node. GND: This is the common ground connection for the Vin and Vout power connections. It is also the 0 VDC reference for the control inputs. Inhibit: The Inhibit pin is an open-collector/drain negative logic input that is referenced to GND. Applying a lowlevel ground signal to this input disables the module's output and turns off the output voltage. When the Inhibit control is active, the input current drawn by the regulator is significantly reduced. If the Inhibit pin is left open-circuit, the module will produce an output whenever a valid input source is applied. Vo Adjust: A 0.1 W, 1 % tolerance (or better) resistor must be connected directly between this pin and pin 7 (GND) to set the output voltage to the desired value. The set point range for the output voltage is from 0.8 V to 3.6 V. The resistor required for a given output voltage may be calculated from the following formula. If left open circuit, the module output will default to its lowest output voltage value. For further information on output voltage adjustment consult the related application note. Rset 0.8 V = 10 k * Vout - 0.8 V - 2.49 k Vo Sense: The sense input allows the regulation circuit to compensate for voltage drop between the module and the load. For optimal voltage accuracy Vo Sense should be connected to Vout. It can also be left disconnected. Track: This is an analog control input that enables the output voltage to follow an external voltage. This pin becomes active typically 20 ms after the input voltage has been applied, and allows direct control of the output voltage from 0 V up to the nominal set-point voltage. Within this range the output will follow the voltage at the Track pin on a volt-for-volt basis. When the control voltage is raised above this range, the module regulates at its set-point voltage. The feature allows the output voltage to rise simultaneously with other modules powered from the same input bus. If unused, the input may be left unconnected. Note: Due to the under-voltage lockout feature, the output of the module cannot follow its own input voltage during power up. For more information, consult the related application note. Margin Down: When this input is asserted to GND, the output voltage is decreased by 5% from the nominal. The input requires an open-collector (open-drain) interface. It is not TTL compatible. A lower percent change can be accomodated with a series resistor. For further information, consult the related application note. Margin Up: When this input is asserted to GND, the output voltage is increased by 5%. The input requires an open-collector (open-drain) interface. It is not TTL compatible. The percent change can be reduced with a series resistor. For further information, consult the related application note. The specification table gives the preferred resistor values for a number of standard output voltages. North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 ATH22T05 Series --5-V Input 22-A, 5-V Input Non-Isolated Wide-Output Adjust Power Module Environmental & Absolute Maximum Ratings Characteristics Track Input Voltage Operating T emperature Range Solder Reflow Temperature Storage T emperature Mechanical Shock Mechanical Vibration Weight Flammability -- -- Symbols Vtrack Ta Treflow Ts (Voltages are with respect to GND) Min -0.3 -40 -40 -- -- -- Typ -- -- -- 500 20 7 Max Vin + 0.3 85 215 (i) 125 -- -- -- Units V C C C G's G's grams Conditions Over Vin Range Surface temperature of module body or pins -- Per Mil-STD-883D, Method 2002.3 1 msec, 1/2 Sine, mounted Mil-STD-883D, Method 2007.2 20-2000 Hz Meets UL 94V-O Notes: (i) During reflow of SMD package version do not elevate peak temperature of the module, pins or internal components above the stated maximum. For further guidance refer to the application note, "Reflow Soldering Requirements for Plug-in Power Surface Mount Products." Specifications Characteristics Output Current (Unless otherwise stated, T a =25 C, V in =5 V, V out =3.3 V, C in =1,000 F, Cout =0 F, and I o =Iomax) Symbols Io Vin Vo tol Regtemp Regline Regload Regtot Conditions 60 C, 200 LFM airflow 25 C, natural convection Over Io range RSET=698 -40 C -- -- -- -- 0.5 5 5 -- 96 94 93 92 91 90 88 20 41 70 120 5 - 8 (3) -- -- 4.3 3.7 -- -- -130 10 300 -- 330 (6) -- Max 22 22 5.5 2 -- -- -- 3 -- -- -- -- -- -- -- -- -- -- -- -- -- -130 -- 4.5 -- (1) (1) Units A V %Vo %Vo mV mV %Vo Input Voltage Range Set-Point Voltage T olerance Temperature Variation Line Regulation Load Regulation Total Output Variation Efficiency (2) (2) % Vo Ripple (pk-pk) Over-Current Threshold Transient Response Vr Io trip ttr Vtr Vo margin IIL margin IIL track dVtrack/dt UVLO VIH VIL IIL inhibit Iin inh s Cin Cout MTBF mVpp A Sec mV % A A V/ms V V A mA kHz F F 106 Hrs Margin Up.Down Adjust Margin Input Current (pins 9 /10) Track Input Current (pin 8) Track Slew Rate Capability Under-Voltage Lockout Inhibit Control (pin3) Input High Voltage Input Low Voltage Input Low Current Input Standby Current Switching Frequency External Input Capacitance External Output Capacitance Reliability (4) Open (4) 0.8 -- -- 340 -- 20,000 -- Per Bellcore TR-332 50 % stress, Ta =40 C, ground benign Notes: (1) See SOA curves or consult factory for appropriate derating. (2) The set-point voltage tolerance is affected by the tolerance and stability of R SET . The stated limit is unconditionally met if RSET has a tolerance of 1 %, with 200 ppm/C or better temperature stability. (3) A small low-leakage (<100 nA) MOSFET is recommended to control this pin. The open-circuit voltage is less than 1 Vdc. (4) This control pin has an internal pull-up to the input voltage Vin. If it is left open-circuit the module will operate when input power is applied. A small low-leakage (<100 nA) MOSFET is recommended for control. For further information, consult the related application note. (5) A 1,000 F electrolytic input capacitor is required for proper operation. The capacitor must be rated for a minimum of 700 mArms of ripple current. (6) An external output capacitor is not required for basic operation. Adding 330 F of distributed capacitance at the load will improve the transient response. North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 ATH22T05 Series--5-V Input 22-A, 5-V Input Non-Isolated Wide-Output Adjust Power Module Typical Characteristics Characteristic Data; Vin =5 V Efficiency vs Load Current 100 (See Note A) Safe Operating Area; Vin =5 V Output Voltage =3.3 V 90 80 (See Note B) Ambient Temperature (C) 90 VOUT 3.3 V 2.5 V 1.8 V 1.5 V 1.2 V 1V 70 60 50 40 30 Airflow 400LFM 200LFM 100LFM Nat Conv Efficiency - % 80 70 60 50 0 4 8 12 16 20 20 0 5 10 15 20 Iout - Amps Iout (A) Output Ripple vs Load Current 50 40 VOUT 2.5 V 1.8 V 3.3 V 1.5 V 1.2 V 1V Vout - mV 30 20 10 0 0 4 8 12 16 20 Iout - Amps Power Dissipation vs Load Current 6 5 4 Pd - Watts 3 2 1 0 0 4 8 12 16 20 Iout - Amps Note A: Characteristic data has been developed from actual products tested at 25C. This data is considered typical data for the Converter. Note B: SOA curves represent the conditions at which internal components are at or below the manufacturer's maximum operating temperatures. Derating limits apply to modules soldered directly to a 4 in. x 4 in. double-sided PCB with 1 oz. copper. North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Application Notes ATH22T033 & ATH22T05 Series Adjusting the Output Voltage of the ATH22T033 & ATH22T05 Wide-Output Adjust Power Modules The Vo Adjust control (pin 4) sets the output voltage of the ATH22T033 and ATH22T05 products. The adjustment range of the ATH22T033 (3.3-V input) is from 0.8 V to 2.5 V 1, and the ATH22T05 (5-V input) from 0.8 V to 3.6 V. The adjustment method requires the addition of a single external resistor, Rset, that must be connected directly between the Vo Adjust and GND pins 2. Table 1-1 gives the preferred value of the external resistor for a number of standard voltages, along with the actual output voltage that this resistance value provides. For other output voltages the value of the required resistor can either be calculated using the following formula, or simply selected from the range of values given in Table 1-2. Figure 1-1 shows the placement of the required resistor. Rset = 10 k * 0.8 V Vout - 0.8 V - 2.49 k Table 1-2; Output Voltage Set-Point Resistor Values Va Req'd 0.800 0.825 0.850 0.875 0.900 0.925 0.950 0.975 1.000 1.025 1.050 1.075 1.100 1.125 1.150 1.175 1.200 1.225 1.250 1.275 1.300 1.325 1.350 1.375 1.400 1.425 1.450 1.475 1.50 1.55 1.60 1.65 1.70 1.75 1.80 1.85 1.90 1.95 Rset Open 318 k 158 k 104 k 77.5 k 61.5 k 50.8 k 43.2 k 37.5 k 33.1 k 29.5 k 26.6 k 24.2 k 22.1 k 20.4 k 18.8 k 17.5 k 16.3 k 15.3 k 14.4 k 13.5 k 12.7 k 12.1 k 11.4 k 10.8 k 10.3 k 9.82 k 9.36 k 8.94 k 8.18 k 7.51 k 6.92 k 6.4 k 5.93 k 5.51 k 5.13 k 4.78 k 4.47 k Va Req'd 2.00 2.05 2.10 2.15 2.20 2.25 2.30 2.35 2.40 2.45 2.50 2.55 2.60 2.65 2.70 2.75 2.80 2.85 2.90 2.95 3.00 3.05 3.10 3.15 3.20 3.25 3.30 3.35 3.40 3.45 3.50 3.55 3.60 Rset 4.18 k 3.91 k 3.66 k 3.44 k 3.22 k 3.03 k 2.84 k 2.67 k 2.51 k 2.36 k 2.22 k 2.08 k 1.95 k 1.83 k 1.72 k 1.61 k 1.51 k 1.41 k 1.32 k 1.23 k 1.15 k 1.07 k 988 914 843 775 710 647 587 529 473 419 367 Table 1-1; Preferred Values of Rset for Standard Output Voltages Vout (Standard) 3.3 V 2 2.5 V 2V 1.8 V 1.5 V 1.2 V 1V 0.8 V Rset (Pref'd Value) 698 2.21 k 4.12 k 5.49 k 8.87 k 17.4 k 36.5 k Open Vout (Actual) 3.309V 2.502 V 2.010 V 1.803 V 1.504 V 1.202 V 1.005 V 0.8 V Figure 1-1; Vo Adjust Resistor Placement VO Sense [Note 3] 10 9 8 5 VO Sense ATH22T05-9S PTH05020W VOUT 6 VOUT Notes: 1. Modules that operate from a 3.3-V input bus should not be adjusted higher than 2.5 V. 2. Use a 0.1 W resistor. The tolerance should be 1 %, with temperature stability of 100 ppm/C (or better). Place the resistor as close to the regulator as possible. Connect the resistor directly between pins 4 and 7 using dedicated PCB traces. 3. Never connect capacitors from Vo Adjust to either GND or Vout. Any capacitance added to the Vo Adjust pin will affect the stability of the regulator. GND 1 GND 7 VO Adj 4 RSET 0.1 W, 1 % COUT 330F North America (USA): 1-888-41-ASTEC + GND Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Application Notes ATH22T033 & ATH22T05 Series ATH22T033/T05: Capacitor Recommendations Input Capacitor The recommended input capacitor(s) is determined by the 1,000 F (1) minimum capacitance and 700 mArms minimum ripple current rating. Ripple current and <100 m equivalent series resistance (ESR) values are the major considerations, along with temperature, when designing with different types of capacitors. Tantalum capacitors have a recommended minimum voltage rating of 2 x (the maximum DC voltage + AC ripple). This is standard practice for tantalum capacitors to insure reliability. Ceramic Capacitors Ceramic capacitors may be substituted for electrolytic types using the minimum capacitance, for improved ripple reduction on the input bus. Output Capacitors (Optional) The recommended ESR of the capacitors is equal to or less than 150 m. Electrolytic capacitors have marginal ripple performance at frequencies greater than 400 kHz but excellent low frequency transient response. Above the ripple frequency, ceramic capacitors are necessary to improve the transient response and reduce any high frequency noise components apparent during higher current excursions. Preferred low ESR type capacitor part numbers are identified in Table 2-1. Tantalum Capacitors Tantalum type capacitors can be used for the output, but only the AVX TPS, Sprague 593D/594/595or Kemet T495/T510 series. These capacitors are recommended over many other tantalum types due to their higher rated surge, power dissipation, and ripple current capability. As a caution the TAJ series by AVX is not recommended. This series has considerably higher ESR, reduced power dissipation, and lower ripple current capability. The TAJ series is less reliable than the AVX TPS series when determining power dissipation capability. Tantalum, ceramic, or Os-con types are recommended for applications where ambient temperatures fall below 0 C. Capacitor Table Table 2-1 identifies the characteristics of capacitors from a number of vendors with acceptable ESR and ripple current (rms) ratings. The number of capacitors required at both the input and output buses is identified for each capacitor type. This is not an extensive capacitor list. Capacitors from other vendors are available with comparable specifications. Those listed are for guidance. The RMS ripple current rating and ESR (at 100kHz) are critical parameters necessary to insure both optimum regulator performance and long capacitor life. Table 2-1: Input/Output Capacitors Capacitor Vendor/ Series Capacitor Characteristics Quantity Working Voltage Panasonic FC (Radial) FK (Surface Mt.) United Chemi-con PXA (Surface Mt.) FX LXZ Series Nichicon PM Series Sanyo-Os-con: SP SVP (Surface Mt.) AVX Tantalum TPS (Surface Mt.) Kemet Polymer Tantalum T520/T530 Series (Surface Mt.) Sprague Tantalum 595D Series (Surface Mt.) 10 V 10 V 25 V 10 V 6.3 V 6.3 V 10 V 10 V 6.3 V 10 V 16 V 10 V 10 V 10 V 10 V 10 V 10 V Value(F) (ESR) Equivalent Series Resistance 0.090 0.068 0060 0.080 0.020 0.013 0.090 0.068 0.053 0.065 0.055 0.015 0.013 0.045 0.060 0.040 0.015 105C Maximum Ripple Current(Irms) 755 mA 1050 mA 1100 mA 850 mA 4130 mA 4935 mA 760 mA 1050 mA 1030 mA 1060mA 4400 mA >4500 mA >5200 mA 1723 mA 1826 mA 1800 mA >3800 mA Physical Size(mm) 10x12.5 10x16 12.5x13.5 10x10.2 10x7.7 10x10.5 10x12.5 10x16 10x12.5 16x15 10x10 10x10.5 10x12.7 7.3L x5.7W x4.1H 4.3W x7.3L x4.0H 7.2L x6W x4.1H Input Bus 2 1 1 1 2 (1) 1 2 1 1 1 1 2 (1) 2 2 (1) 2 (1) 3 3 Output Bus 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Vendor Part Number 560 1000 1000 1000 470 1000 680 1000 1000 1000 1000 470 560 470 470 330 330 EEUFC1A561 EEUFC1A102 EEVFK1E102Q EEVFK1A102P PXA6.3VC471MJ80TP 6FX1000M LXZ10VB681M10X12LL LXZ10VB102M10X16LL UHD0J102MPR UPM1A102MPH6 UPM1C 102MHH6 10SP470M 10SVP560M TPSE477M010R0045 TPSV477M010R0060 T520X337M010AS T530X337M010AS 10 V 470 0.100 1440 mA 2 (1) 1 595D477X0010R2T (1) Total capacitance of 940 F is acceptable based on the combined ripple current rating. North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Application Notes ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) Features of the ATH Family of Non-Isolated Wide Output Adjust Power Modules Point-of-Load Alliance The ATH family of non-isolated, wide-output adjust power modules are optimized for applications that require a flexible, high performance module that is small in size. These products are part of the "Point-of-Load Alliance" (POLA), which ensures compatible footprint, interoperability and true second sourcing for customer design flexibility. The POLA is a collaboration between Texas Instruments, Artesyn Technologies, and Astec Power to offer customers advanced non-isolated modules that provide the same functionality and form factor. Product series covered by the alliance includes the ATH06 (6 A), ATH10 (10 A), ATH12/15 (12/15 A), ATH18/22 (18/22 A), and the ATH26/30 (26/30 A). From the basic, "Just Plug it In" functionality of the 6-A modules, to the 30-A rated feature-rich ATH30 Series, these products were designed to be very flexible, yet simple to use. The features vary with each product. Table 3-1 provides a quick reference to the available features by product and input bus voltage. Table 3-1; Operating Features by Series and Input Bus Voltage This is a feature unique to the ATH family, and was specifically designed to simplify the task of sequencing the supply voltage in a power system. These and other features are described in the following sections. Power-Up Characteristics When configured per their standard application all the ATH products will produce a regulated output voltage following the application of a valid input source voltage. All the modules include soft-start circuitry. This slows the initial rate in which the output voltage can rise, thereby limiting the amount of in-rush current that can be drawn from the input source. The soft-start circuitry also introduces a short time delay (typically 5 ms-10 ms) into the power-up characteristic. This delay is from the point that a valid input source is recognized, to the initial rise of the output voltage. Figure 3-1 shows the power-up characteristic of the 22-A output product (ATH22T05-9xx), operating from a 5-V input bus and configured for a 3.3-V output. The waveforms were measured with a 5-A resistive load. The initial rise in input current when the input voltage first starts to rise is the charge current drawn by the input capacitors. Figure 3-1 Thermal Shutdown Margin Up/Down Pre-Bias Startup Output Sense Vo (2V/Div) On/Off Inhibit Auto-TrackTM Over-Current Adjust (Trim) Series PTHxx050 ATH06 Input Bus 3.3 V 5V 12 V I OUT 6A 6A 6A 10 A Iin (2A/Div) ATH10 PTHxx060 3.3 V / 5 V 12 V 10A 8A 15 A 12 A 22 A 18 A 30 A 26 A PTHxx010 ATH12/15 3.3 V / 5 V 12 V PTHxx020 ATH18/22 3.3 V / 5 V 12 V PTHxx030 ATH26/30 3.3 V / 5 V 12 V * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Vin (5V/Div) * * * * * * * * * * * * * * * * HORIZ SCALE: 10ms/Div * * * * Over-Current Protection For protection against load faults, all modules incorporate output over-current protection. Applying a load that exceeds the regulator's over-current threshold will cause the regulated output to shut down. Following shutdown a module will periodically attempt to recover by initiating a soft-start power-up. This is described as a "hiccup" mode of operation, whereby the module continues in a cycle of successive shutdown and power up until the load fault is removed. During this period, the average current flowing into the fault is significantly reduced. Once the fault is removed, the module automatically recovers and returns to normal operation. For simple point-of-use applications, the ATH06 (6A) provides operating features such as an on/off inhibit, output voltage trim, pre-bias startup (3.3/5-V input only), and over-current protection. The ATH10 (10 A), and ATH12/15 (12/15 A) include an output voltage sense, and margin up/down controls. Then the higher output current, ATH18/22 (18/22A) and ATH26/30 (26/30A) products incorporate over-temperature shutdown protection. All of the products referenced in Table 3-1 include Auto-TrackTM. North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Application Notes ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) Output On/Off Inhibit For applications requiring output voltage on/off control, each series of the ATH family incorporates an output Inhibit control pin. The inhibit feature can be used wherever there is a requirement for the output voltage from the regulator to be turned off. The power modules function normally when the Inhibit pin is left open-circuit, providing a regulated output whenever a valid source voltage is connected to Vin with respect to GND. Figure 3-2 shows the typical application of the inhibit function. Note the discrete transistor (Q1). The Inhibit control has its own internal pull-up to Vin potential. The input is not compatible with TTL logic devices. An opencollector (or open-drain) discrete transistor is recommended for control. Turning Q1 on applies a low voltage to the Inhibit control pin and disables the output of the module. If Q1 is then turned off, the module will execute a soft-start power-up sequence. A regulated output voltage is produced within 20 msec. Figure 3-3 shows the typical rise in both the output voltage and input current, following the turn-off of Q1. The turn off of Q1 corresponds to the rise in the waveform, Q1 Vds. The waveforms were measured with a 5-A load. Figure 3-2 Vo Sense Remote Sense The ATH10, ATH12/15, ATH18/22, and ATH26/30 products incorporate an output voltage sense pin, Vo Sense. The Vo Sense pin should be connected to Vout at the load circuit (see data sheet standard application). A remote sense improves the load regulation performance of the module by allowing it to compensate for any `IR' voltage drop between itself and the load. An IR drop is caused by the high output current flowing through the small amount of pin and trace resistance. Use of the remote sense is optional. If not used, the Vo Sense pin can be left open-circuit. An internal low-value resistor (15- or less) is connected between the Vo Sense and Vout. This ensures the output voltage remains in regulation. With the sense pin connected, the difference between the voltage measured directly between the Vout and GND pins, and that measured from V o Sense to GND, is the amount of IR drop being compensated by the regulator. This should be limited to a maximum of 0.3 V. Note: The remote sense feature is not designed to compensate for the forward drop of non-linear or frequency dependent components that may be placed in series with the converter output. Examples include OR-ing diodes, filter inductors, ferrite beads, and fuses. When these components are enclosed by the remote sense connection they are effectively placed inside the regulation control loop, which can adversely affect the stability of the regulator. 10 9 8 5 Over-Temperature Protection 6 VIN 2 ATH15T05-9S PTH05020W VOUT 3 1 7 4 CIN 1,000 F 1 =Inhibit GND RSET Q1 BSS138 COUT 330 F L O A D GND Figure 3-3 The ATH18/22 and ATH26/30 series of products have over-temperature protection. These products have an on-board temperature sensor that protects the module's internal circuitry against excessively high temperatures. A rise in the internal temperature may be the result of a drop in airflow, or a high ambient temperature. If the internal temperature exceeds the OTP threshold, the module's Inhibit control is automatically pulled low. This turns the output off. The output voltage will drop as the external output capacitors are discharged by the load circuit. The recovery is automatic, and begins with a soft-start power up. It occurs when the the sensed temperature decreases by about 10 C below the trip point. Note: The over-temperature protection is a last resort mechanism to prevent thermal stress to the regulator. Operation at or close to the thermal shutdown temperature is not recommended and will reduce the long-term reliability of the module. Always operate the regulator within the specified Safe Operating Area (SOA) limits for the worst-case conditions of ambient temperature and airflow. Vo (2V/Div) Iin (2A/Div) Q1Vds (5V/Div) HORIZ SCALE: 10ms/Div North America (USA): 1-888-41-ASTEC + + Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Application Notes ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) Auto-TrackTM Function The Auto-TrackTM function is unique to the ATH family, and is available with the all "Point-of-Load Alliance" (POLA) products. Auto-TrackTM was designed to simplify the amount of circuitry required to make the output voltage from each module power up and power down in sequence. The sequencing of two or more supply voltages during power up is a common requirement for complex mixed-signal applications, that use dual-voltage VLSI ICs such as DSPs, micro-processors, and ASICs. each module will rise in unison with other modules, to its respective set-point voltage. Figure 3-5 shows the output voltage waveforms from the circuit of Figure 3-4 after the On/Off Control is set from a high to a low-level voltage. The waveforms, Vo1 and Vo2 represent the output voltages from the two power modules, U1 (3.3 V) and U2 (2.0 V) respectively. Vo1 and Vo2 are shown rising together to produce the desired simultaneous power-up characteristic. The same circuit also provides a power-down sequence. Power down is the reverse of power up, and is accomplished by lowering the track control voltage back to zero volts. The important constraint is that a valid input voltage must be maintained until the power down is complete. It also requires that Q1 be turned off relatively slowly. This is so that the Track control voltage does not fall faster than Auto-Track's slew rate capability, which is 5 V/ms. The components R1 and C1 in Figure 3-4 limit the rate at which Q1 can pull down the Track control voltage. The values of 100 k-ohm and 0.047 F correlate to a decay rate of about 0.6 V/ms. The power-down sequence is initiated with a low-to-high transition at the On/Off Control input to the circuit. Figure 3-6 shows the power-down waveforms. As the Track control voltage falls below the nominal set-point voltage of each power module, then its output voltage decays with all the other modules under Auto-TrackTM control. How Auto-TrackTM Works Auto-TrackTM works by forcing the module's output voltage to follow a voltage presented at the Track control pin. This control range is limited to between 0 V and the module's set-point voltage. Once the track-pin voltage is raised above the set-point voltage, the module's output remains at its set-point 1. As an example, if the Track pin of a 2.5-V regulator is at 1 V, the regulated output will be 1 V. But if the voltage at the Track pin rises to 3 V, the regulated output will not go higher than 2.5 V. When under track control, the regulated output from the module follows the voltage at its Track pin on a voltfor-volt basis. By connecting the Track pin of a number of these modules together, the output voltages will follow a common signal during power-up and power-down. The control signal can be an externally generated master ramp waveform, or the output voltage from another power supply circuit 3. The Track control also incorporates an internal RC charge circuit. This operates off the module's input voltage to produce a suitable rising waveform at power up. Notes on Use of Auto-TrackTM 1. The Track pin voltage must be allowed to rise above the module's set-point voltage before the module can regulate at its adjusted set-point voltage. 2. The Auto-TrackTM function will track almost any voltage ramp during power up, and is compatible with ramp speeds of up to 5 V/ms. 3. The absolute maximum voltage that may be applied to the Track pin is Vin. 4. The module will not follow a voltage at its Track control input until it has completed its soft-start initialization. This takes about 10 ms from the time that the module has sensed that a valid voltage has been applied its input. During this period, it is recommended that the Track pin be held at ground potential. 5. Once its soft-start initialization is complete, the module is capable of both sinking and sourcing current when following the voltage at the Track pin. 6. The Auto-TrackTM function can be disabled by connecting the Track pin to the input voltage (Vin) through a 1-k resistor. When Auto-TrackTM is disabled, the output voltage will rise faster following the application of input power. **Auto-Track is a trademark of Texas Instruments, Inc. Typical Application The basic implementation of Auto-TrackTM allows for simultaneous voltage sequencing of a number of AutoTrackTM compliant modules. Connecting the Track control pins of two or more modules forces the Track control of all modules to follow the same collective RC ramp waveform, and allows them to be controlled through a single transistor or switch; Q1 in Figure 3-4. To initiate a power-up sequence, it is recommended that the Track control be first pulled to ground potential. This should be done at or before input power is applied to the modules, and then held for at least 10 ms thereafter. This brief period gives the modules time to complete their internal soft-start initialization. Applying a logiclevel high signal to the circuit's On/Off Control turns Q1 on and applies a ground signal to the Track pins. After completing their internal soft-start intialization, the output of all modules will remain at zero volts while Q1 is on. 10 ms after a valid input voltage has been applied to the modules, Q1 may be turned off. This allows the track control voltage to automatically rise toward to the modules' input voltage. During this period the output voltage of North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Application Notes ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) Figure 3-4; Sequenced Power Up & Power Down Using Auto-Track U1 10 9 8 Track 5 6 +5V CIN + 2 VIN Inhibit 3 ATH22T05-9SJ PTH05020W GND 1 7 R2 698 Vo1 =3.3V + Vo2 =2V + Vo1 (1V/Div) Vo2 (1V/Div) On/Off Control (5V/Div) VO 4 COUT C1 0.047F U2 On/Off Control 1 = Power Down 0 = Power Up R1 100k Q1 BSS138 2 VIN Inhibit 3 10 9 8 Track 5 6 ATH15T05-9SJ PTH05010W GND 1 7 R3 4k12 VO 0V CIN Figure 3-5; Simultaneous Power Up with Auto-Track Control Vo1 (1V/Div) Vo2 (1V/Div) On/Off Input (5V/Div) HORIZ SCALE: 5ms/Div North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 + 4 COUT Figure 3-6; Simultaneous Power Down with Auto-Track Control HORIZ SCALE: 5ms/Div Asia (HK): 852-2437-9662 Application Notes ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) Margin Up/Down Controls The ATH10 (10A), ATH12/15 (12/15A), ATH18/22 (18/ 22A) and ATH26/30 (26/30A) products incorporate Margin Up and Margin Down control inputs. These controls allow the output voltage to be momentarily adjusted 1, either up or down, by a nominal 5 %. This provides a convenient method for dynamically testing the operation of the load circuit over its supply margin or range. It can also be used to verify the function of supply voltage supervisors. The 5 % change is applied to the adjusted output voltage, as set by the external resistor, Rset at the Vo Adjust pin. The 5 % adjustment is made by pulling the appropriate margin control input directly to the GND terminal 2. A low-leakage open-drain device, such as an n-channel MOSFET or p-channel JFET is recommended for this purpose 3. Adjustments of less than 5 % can also be accommodated by adding series resistors to the control inputs (See Figure 3-4). The value of the resistor can be selected from Table 3-2, or calculated using the following formula. Notes: 1. The Margin Up* and Margin Dn* controls were not intended to be activated simultaneously. If they are their affects on the output voltage may not completely cancel, resulting in the possibility of a slightly higher error in the output voltage set point. 2. The ground reference should be a direct connection to the module GND at pin 7 (pin 1 for the ATH06). This will produce a more accurate adjustment at the load circuit terminals. The transistors Q1 and Q2 should be located close to the regulator. 3. The Margin Up and Margin Dn control inputs are not compatible with devices that source voltage. This includes TTL logic. These are analog inputs and should only be controlled with a true open-drain device (preferably a discrete MOSFET transistor). The device selected should have low off-state leakage current. Each input sources 8 A when grounded, and has an open-circuit voltage of 0.8 V. Up/Down Adjust Resistance Calculation To reduce the margin adjustment to something less than 5 %, series resistors are required (See RD and RU in Figure 3-7). For the same amount of adjustment, the resistor value calculated for RU and RD will be the same. The formulas is as follows. RU or RD = 499 % - 99.8 k Table 3-2; Margin Up/Down Resistor Values % Adjust 5 4 3 2 1 RU / RD 0.0 k 24.9 k 66.5 k 150.0 k 397.0 k Where % = The desired amount of margin adjust in percent. Figure 3-7; Margin Up/Down Application Schematic 10 1 9 8 7 +Vo 0V PTH05010W ATH15T05-9S VIN (Top View) 3 4 5 2 6 +VOUT + Cin MargDn RD RU RSET 0.1 W, 1 % + Cout L O A D Q1 Q2 MargUp GND GND North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Application Notes ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) Pre-Bias Startup Capability Only selected products in the ATH family incorporate this capability. Consult Table 3-1 to identify which products are compliant. A pre-bias startup condition occurs as a result of an external voltage being present at the output of a power module prior to its output becoming active. This often occurs in complex digital systems when current from another power source is backfed through a dual-supply logic component, such as an FPGA or ASIC. Another path might be via clamp diodes as part of a dual-supply power-up sequencing arrangement. A prebias can cause problems with power modules that incorporate synchronous rectifiers. This is because under most operating conditions, these types of modules can sink as well as source output current. The ATH family of power modules incorporate synchronous rectifiers, but will not sink current during startup 1, or whenever the Inhibit pin is held low. However, to ensure satisfactory operation of this function, certain conditions must be maintained. 2 Figure 3-7 shows an application demonstrating the pre-bias startup capability. The startup waveforms are shown in Figure 3-9. Note that the output current from the ATH15T033-9xx (Io) shows negligible current until its output voltage rises above that backfed through diodes D1 and D2. Note: The pre-bias start-up feature is not compatible with Auto-Track. When the module is under Auto-Track control, it is fully active and will sink current if the output voltage is below that of a back-feeding source. Therefore to ensure a prebias hold-off, one of two approaches must be followed when input power is applied to the module. The Auto-Track function must either be disabled 3, or the module's output held off using the Inhibit pin. The latter allows Auto-Track's internal (RC) voltage ramp to rise above the set-point voltage. Notes 1. Startup is the relatively short period (approx. 10 ms) prior to the output voltage rising. The startup period immediately follows either the application of a valid input source voltage, or the release of a ground signal at the Inhibit pin. 2. To ensure that the regulator does not sink current when power is first applied (even with a ground signal applied to the Inhibit control pin), the input voltage must always be greater than the output voltage throughout the power-up and power-down sequence. 3. The Auto-Track function can be disabled at power up by immediately applying a voltage to the module's Track pin that is greater than its set-point voltage. This can be easily accomplished by connecting the Track pin to Vin through a 1-k resistor. Figure 3.9; Pre-Bias Startup Waveforms Vin (1 V/Div) Vo (1 V/Div) Io (5 A/Div) HORIZ SCALE: 5 ms/Div Figure 3.8; Application Circuit Demonstrating Pre-Bias Startup VIN = 3.3 V R1 1k0 10 2 9 8 Track VIN 5 Sense VO Vadj 7 4 R2 2k21 6 ATH15T033-9S PTH03010W GND 1 Vo = 2.5 V + Io D1, D2 MBR3100 Inhibit 3 VCORE + VCCIO CIN 330 F + COUT 330 F ASIC North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Through Hole Termination Surface Mount Termination |
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