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TK732xx
LOW DROPOUT REGULATOR FEATURES
s Up to 5 A Output Current Capability With External PNP Transistor s Internal Short Circuit Protection s Excellent Load Regulation s CMOS/TTL-Compatible On/Off Switch s Internal Reverse Bias Current Protection Switch s Internal Thermal Shutdown s Broad Operating Voltage Range s High Impedance VSENSE Pin (Off Mode) s Continuous and Pulsed Current Modes
APPLICATIONS
s s s s s s s s s s Battery Powered Systems Cellular/Cordless Telephones Radio Control Systems Wireless Communications Systems Portable Instrumentations Portable Computers Personal Digital Assistants Local Area Network (LAN) Receivers Lithium Ion Battery Chargers Power Recovery for Microprocessors
DESCRIPTION
The TK732xx is a controller IC for a low dropout voltage regulator. The TK732xx and the external PNP power transistor provide standard output voltages from 2 to 11 V and output current from 100 mA to 5 A. By utilizing an external PNP power transistor, low dropout voltage at high current can be readily achieved. The internal electronic switch can be controlled by TTL or CMOS logic levels. The device is in the "on" state when the control pin is pulled to a high logic level. A pin for a bypass capacitor, which connects to the internal circuitry, is provided to lower the overall output noise level. The current limit characteristics can be configured as continuous (constant current) or pulsed (cycling). An internal thermal shutdown circuit limits the junction temperatures to below 150 C. In the "off" mode, the output of the regulator becomes a high impedance. This prevents the output capacitor from being rapidly discharged for backup to the load.
TK732xx
CONTROL NOISE BYPASS
01 S
BASE
VSENSE GND
CPULSE VIN
IPK
BLOCK DIAGRAM
VIN IPK CPULSE BASE VSENSE
ORDERING INFORMATION
TK732
Voltage Code Package Code
VOLTAGE CODE
20 = 2.0 V * 21 = 2.1 V * 22 = 2.2 V * 23 = 2.3 V * 24 = 2.4 V 25 = 2.5 V 26 = 2.6 V 27 = 2.7 V 28 = 2.8 V 29 = 2.9 V 30 = 3.0 V 31 = 3.1 V 32 = 3.2 V 33 = 3.3 V 34 = 3.4 V 35 = 3.5 V 36 = 3.6 V 37 = 3.7 V 38 = 3.8 V 39 = 3.9 V 40 = 4.0 V 41 = 4.1 V 42 = 4.2 V 43 = 4.3 V
ML
Grade Tape/Reel Code Temp. Code
TAPE/REEL CODE PACKAGE CODE
ON/OFF CIRCUIT
THERMAL SENSOR
CONTROL
M: SOT-23L-8 44 = 4.4 V L: Tape Left 45 = 4.5 V 46 = 4.6 V GRADE TEMP. RANGE 47 = 4.7 V None: Standard 2% C: -30 to 80 C ** 48 = 4.8 V I : -40 to 85 C H: High (Special) *** 49 = 4.9 V 50 = 5.0 V 55 = 5.5 V * * Unavailable with I Rank Specified 70 = 7.0 V * ** unless Otherwise TK73242MCLH Available Only *** TK73241MCLH, 80 = 8.0 V 11 = 11.0 V
BANDGAP REFERENCE LEAKAGE PROTECTION
GND
NOISE BYPASS
January 1999 TOKO, Inc.
Page 1
TK732xx
ABSOLUTE MAXIMUM RATINGS (STANDARD DEVICES) (NOTE 6)
Supply Voltage Range ............................................ 19 V Power Dissipation (Note 1) ................................ 600 mW Reverse Bias Voltage Range ..................................... 6 V Noise Bypass Pin Terminal Voltage Range ............... 5 V Control Pin Terminal Voltage Range ........................ 14 V Storage Temperature Range ................... -55 to +150 C Operating Temperature Range ...................-30 to +80 C Extended Temperature Range ................... -40 to +85 C Operating Voltage Range ............................ 1.8 to 14.0 V Junction Temperature ........................................... 150 C Lead Soldering Temperature (10 s) ...................... 235 C
TK732xx ELECTRICAL CHARACTERISTICS (STANDARD DEVICES)
Test conditions: VIN = VOUT(TYP) + 1 V, TA = 25 C, unless otherwise specified. SYMBOL IQ ISTBY IR(LEAK) IOUT VOUT VDROP Line Reg Load reg IBASE(L) IBASE(H) VSENSE PARAMETER Quiescent Current Standby Current Reverse Bias Leakage (Note 5) Output Current Output Voltage Dropout Voltage Line Regulation Load Regulation Base Current LOW Base Current HIGH Current Limit Detect Voltage Pulse Current Limit Mode f = 400 Hz, CL = 10 F, CN = 0.1 F, VIN = VOUT(TYP) = 1.5 V, IOUT = 30 mA, VRIPPLE = 100 mVrms, (Note 3) f = 1 kHz, BPF = 400 Hz to 30 kHz, (Note 3) (Note 4) 15 70 90 110 mV TEST CONDITIONS IOUT = 0 mA, Excluding ICONT VIN = 8 V, Output OFF VR = 5 V, Excluding External Transistor, Output OFF External Transistor Dependent IOUT = 30 mA, See Table 1 External Transistor Dependent VIN = VOUT(TYP) + 1 V to VOUT(TYP) + 6 V (Note 2) External Transistor Dependent 1.8 V VIN 4 V 4.1 V VIN 12 V Continuous Current Limit Mode 15 40 80 100 120 N/A 3.0 10 20 2 N/ A MIN TYP 250 MAX 360 0.1 50 UNITS A A nA A V V mV mV mA mA mV
RR
Ripple Rejection
57
dB
VNO IPULSE
Output Noise CPULSE Pin Terminal Current
0.13 25 20 1.25 45
V/ Hz A ppm/ C V
VOUT /T Temperature Coefficient Vref Reference Voltage
CONTROL TERMINAL SPECIFICATIONS ICONT VCONT(ON) VCONT(OFF) Page 2 Control Current Control Voltage (ON) Control Voltage (OFF) VCONT = 1.8 V, Output ON Output ON Output OFF 1.8 0.6 6.5 20 A V V
January 1999 TOKO, Inc.
TK732xx
TK732xx ELECTRICAL CHARACTERISTICS (STANDARD DEVICES) CONT.
Note 1: Power dissipation is 600 mW when mounted as recommended. Derate at 4.8 mW/C for operation above 25 C. Note 2: Refer to :Definition of Terms." Note 3: Ripple rejection and noise voltage are affected by the value and characteristics of the capacitor used. Note 4: This pin is used for Pulse Current Limit Mode. When selecting Continuous Current Limit Mode, this pin is connected to GND. Note 5: Not applicable for VOUT > 4.8 V. Note 6: The voltage applied to any pin must be greater than -0.4 V. Gen. Note: Parameters with min. or max. values are 100% tested at TA = 25 C.
TK732xx ELECTRICAL CHARACTERISTICS TABLE 1 (STANDARD DEVICES)
Test Conditions: VIN = VOUT(TYP) + 1 V, IOUT = 30 mA, TA = 25 C, unless otherwise specified.
Room Temp. Range (TA = 25 C) Output Voltage 2.0 V 2.1 V 2.2 V 2.3 V 2.4 V 2.5 V 2.6 V 2.7 V 2.8 V 2.9 V 3.0 V 3.1 V 3.2 V 3.3 V 3.4 V 3.5 V 3.6 V 3.7 V 3.8 V 3.9 V 4.0 V 4.1 V 4.2 V 4.3 V 4.4 V 4.5 V 4.6 V 4.7 V 4.8 V 4.9 V 5.0 V 5.5 V 7.0 V 6.0 V 11.0 V Voltage Code 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 55 70 80 11 VOUT(MIN) 1.940 V 2.040 V 2.140 V 2.240 V 2.340 V 2.440 V 2.540 V 2.640 V 2.740 V 2.840 V 2.940 V 3.040 V 3.140 V 3.240 V 3.335 V 3.435 V 3.535 V 3.630 V 3.725 V 3.825 V 3.920 V 4.020 V 4.120 V 4.215 V 4.315 V 4.410 V 4.510 V 4.605 V 4.705 V 4.800 V 4.900 V 5.390 V 6.860 V 7.840 V 10.78 V VOUT(MAX) 2.060 V 2.160 V 2.260 V 2.360 V 2.460 V 2.560 V 2.660 V 2.760 V 2.860 V 2.960 V 3.060 V 3.160 V 3.260 V 3.360 V 3.465 V 3.565 V 3.665 V 3.770 V 3.875 V 3.975 V 4.080 V 4.180 V 4.280 V 4.385 V 4.485 V 4.590 V 4.690 V 4.795 V 4.895 V 5.000 V 5.100 V 5.610 V 7.140 V 8.160 V 11.22 V Full Temp. Range (TA = -40 to +85 C)
(Applies to "I" Rank Only)
VOUT(MIN)
VOUT(MAX)
2.300 V 2.400 V 2.500 V 2.600 V 2.700 V 2.800 V 2.900 V 3.000 V 3.095 V 3.190 V 3.290 V 3.385 V 3.485 V 3.580 V 3.675 V 3.770 V 3.870 V 3.965 V 4.060 V 4.160 V 4.255 V 4.350 V 4.450 V 4.545 V 4.640 V 4.740 V 4.835 V
2.500 V 2.600 V 2.700 V 2.800 V 2.900 V 3.000 V 3.100 V 3.200 V 3.305 V 3.410 V 3.510 V 3.615 V 3.720 V 3.820 V 3.925 V 4.030 V 4.130 V 4.235 V 4.335 V 4.440 V 4.545 V 4.645 V 4.750 V 4.850 V 4.955 V 5.060 V 5.165 V
7.745 V 10.650 V
8.265 V 11.365 V
January 1999 TOKO, Inc.
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TK732xx
ABSOLUTE MAXIMUM RATINGS (SPECIAL DEVICES) (Note 6)
Supply Voltage Range ............................................ 19 V Power Dissipation (Note 1) ................................ 600 mW Reverse Bias Voltage Range ..................................... 6 V Noise Bypass Pin Terminal Voltage Range ............... 5 V Control Pin Terminal Voltage Range ........................ 14 V Storage Temperature Range ................... -55 to +150 C Operating Temperature Range ...................-10 to +60 C Operating Voltage Range ............................ 1.8 to 14.5 V Junction Temperature ........................................... 150 C Lead Soldering Temperature (10 s) ...................... 235 C
TK73241MCLH, TK73242MCLH ELECTRICAL CHARACTERISTICS
Test conditions: VIN = VOUT(TYP) + 1 V, TA = 25 C, unless otherwise specified.
SYMBOL IQ ISTBY IR(LEAK) IOUT VOUT VDROP Line Reg Load reg IBASE VSENSE PARAMETER Quiescent Current Standby Current Reverse Bias Leakage (Note 5) Output Current Output Voltage Dropout Voltage Line Regulation Load Regulation Base Current Continuous Current Limit Mode Current Limit Detect Voltage Pulse Current Limit Mode f = 400 Hz, CL = 10 F, CN = 0.1 F, VIN = VOUT(TYP) = 1.5 V, IOUT = 30 mA, VRIPPLE = 100 mVrms, (Note 3) f = 1 kHz, BPF = 400 Hz to 30 kHz, (Note 3) (Note 4) 15 75 90 105 mV TEST CONDITIONS IOUT = 0 mA, Excluding ICONT VIN = 8 V, Output OFF VR = 5 V, Excluding External Transistor, Output OFF External Transistor Dependent IOUT = 30 mA, See Table 2 External Transistor Dependent VIN = VOUT(TYP) + 1 V to VOUT(TYP) + 6 V (Note 2) External Transistor Dependent 50 85 100 115 N/ A 3.0 10 20 2 N/ A MIN TYP 240 MAX 300 0.1 50 UNITS A A nA A V V mV mV mA mV
RR
Ripple Rejection
57
dB
VNO IPULSE
Output Noise CPULSE Pin Terminal Current
0.13 25 20 1.25 45
V/ Hz A ppm/ C V
VOUT /T Temperature Coefficient Vref Reference Voltage
CONTROL TERMINAL SPECIFICATIONS ICONT VCONT(ON) VCONT(OFF) Control Current Control Voltage (ON) Control Voltage (OFF) VCONT = 1.8 V, Output ON Output ON Output OFF 1.8 0.6 6.5 20 A V V
Page 4
January 1999 TOKO, Inc.
TK732xx
TK73241MCLH, TK73242MCLH ELECTRICAL CHARACTERISTICS CONT.
Note 1: Power dissipation is 600 mW when mounted as recommended. Derate at 4.8 mW/C for operation above 25 C. Note 2: Refer to "Definition of Terms." Note 3: Ripple rejection and noise voltage are affected by the value and characteristics of the capacitor used. Note 4: This pin is used for Pulse Current Limit Mode. When selecting Continuous Current Limit Mode, this pin is connected to GND. Note 5: Not applicable for VOUT > 4.8 V. Note 6: The voltage applied to any pin must be greater than -0.4 V. Gen. Note: Parameters with min. or max. values are 100% tested at TA = 25 C.
TK73241MCLH, TK73242MCLH ELECTRICAL CHARACTERISTICS TABLE 2
Test Conditions: VIN = VOUT(TYP) + 1 V, IOUT = 30 mA, TA = 25 C, unless otherwise specified.
Room Temp. Range (TA = 25 C) VOUT(MIN) VOUT(MAX) 4.067 V 4.167 V 4.133 V 4.233 V Full Temp. Range (TA = -10 to +60 C) VOUT(MIN) VOUT(MAX) 4.050 V 4.150 V 4.150 V 4.250 V
Output Voltage
Voltage Code
4.1 V 4.2 V
41 42
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TK732xx
TEST CIRCUIT
CP CN RP
VIN
Note:Transistor: 2SB1115 CN = 0.1 F CP = 0.1 F CL = 4.7 F RP = 330 k Continuous Current Limit Mode: ISET (mA) = 100 mV / RIPK () Pulse Current Limit Mode: ISET (mA) = 90 mV / RIPK ()
CIN
RIPK
TK732xx
CONT
EMITTER
BASE
EXTERNAL TRANSISTOR
CL
COLLECTOR VOUT
TA = 25 C, external transistor is 2SB1115(NEC), unless otherwise specified.
LINE REGULATION 1 LINE REGULATION 2 LOAD REGULATION
TYPICAL PERFORMANCE CHARACTERISTICS
VOUT (50 mV/ DIV)
VOUT (10 mV/ DIV)
VOUT (5 mV/ DIV)
VOUT TYPICAL
0
10 VIN (V)
20
0
10 VIN (V)
20
0
500 IOUT (mA)
1000
QUIESCENT CURRENT VS. OUTPUT VOLTAGE 5 4 IQ (mA) 3 VOUT = 5.0 V 2 1 0 0 10 VIN (V) 20 0 0 -100 VDROP (mV) -200 -300 -400
DROPOUT VOLTAGE VS. OUTPUT VOLTAGE 5 2SB799 2SB1115 2SB1114 2SB1302 IGND (mA) 4 3 2 1 0
GROUND CURRENT VS. OUTPUT VOLTAGE
VOUT = 3.0 V
500 IOUT (mA)
1000
0
500 IOUT (mA)
1000
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January 1999 TOKO, Inc.
TK732xx
TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)
TA = 25 C, external transistor is 2SB1115(NEC), unless otherwise specified.
BASE CURRENT DRIVE VS. INPUT VOLTAGE
CURRENT LIMIT DETECTOR VOLTAGE VS. INPUT VOLTAGE CONTINUOUS CURRENT LIMIT MODE 100 100
REVERSE BIAS CURRENT (VIN = 0 TO 6 V)
1E-6 IREV (A)
V (mV)
IB (mA)
PULSE CURRENT LIMIT MODE 50 50
1E-9
VIN = 0 V VIN = 6 V VIN = 4 V VIN = 2 V
1E-12 0 5 VIN (V) 10 15 0 5 VIN (V) 10 15 0 5 VREV (V) 10
QUIESCENT CURRENT VS. INPUT VOLTAGE (OFF MODE)
0 -20
RIPPLE REJECTION
CN = NONE
VIN 732xx VOUT
1E-6
RR (dB)
IQ (A)
-40 -60
CN = 0.01 F
VCONT CN RCONT
CL 4.7 F
1E-9
-80
CN = 0.1 F
RIPPLE REJECTION CIRCUIT
1E-12 0 10 VIN (V) CONTROL CURRENT VS. TEMPERATURE 50 40
ICONT (A)
20
-100 0.01
0.1
1 f (kHz)
10
100
CONTROL VOLTAGE (OUTPUT ON POINT) VS. TEMPERATURE 2.0 RCONT = 0 50 30
VOUT (mV)
OUTPUT VOLTAGE VARIATION VS. TEMPERATURE
VCONT = 5 V VCONT (V)
VOUT TYPICAL 10 -10 -30 -50 -50
30 20 10 0 -50 VCONT = 2 V
1.0
0 TA (C)
50
100
-50
0 TA (C)
50
100
0 TA (C)
50
100
January 1999 TOKO, Inc.
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TK732xx
TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)
TA = 25 C, external transistor is 2SB1115(NEC), unless otherwise specified.
CONTROL PIN VOLTAGE VS. CONTROL CURRENT
5000
ON/OFF TRANSIENT CL = 100 F RISE TIME (s) 1000 CL = 4.7 F
ON/OFF STEP RESPONSE
50 40
VCONT (V)
VOUT RCONT = 0 k
ON/OFF CONTROL
30 20 10
RCONT = 100 k
CL = 22 F 100
CL = 4.7 F OR 10 F
CL = 4.7 F CN = NONE
RCONT = 200 k 0 -50 0 50 100
10 0.001
0.01 CN (F)
0.1
10
VOUT
0
10
20
30
ICONT (A)
TIME (s)
LOAD CURRENT STEP RESPONSE
LINE CURRENT STEP RESPONSE
VOUT + 2 V
VOUT (200 mV/ DIV)
VOUT (20 mV/ DIV)
VIN
IOUT = 0 TO 300 mA CL = 47 OR 100 F CL = 22 F CL = 10 F CL = 4.7 F 0 5 10 TIME (s) 15 20
VOUT + 1 V
CN = NONE CN = 0.1 F
VOUT
IOUT = 50 mA
TIME (s)
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January 1999 TOKO, Inc.
TK732xx
DEFINITION AND EXPLANATION OF TECHNICAL TERMS
OUTPUT VOLTAGE (VOUT) The output voltage is specified with VIN = (VOUT(TYP) + 1 V) and IOUT = 30 mA. DROPOUT VOLTAGE (VDROP) The dropout voltage is the difference between the input voltage and the output voltage at which point the regulator starts to fall out of regulation. Below this value, the output voltage will fall as the input voltage is reduced. It is dependent upon the load current, the external transistor and the junction temperature. BASE CONTROL CURRENT (IBASE) The base control current is the drive current for the base of the external transistor. OUTPUT CURRENT (IOUT) The output current depends on the characteristics of the external transistor and current limit setting. LINE REGULATION (Line Reg) Line regulation is the ability of the regulator to maintain a constant output voltage as the input voltage changes. The line regulation is specified as the input voltage is changed from VIN = VOUT(TYP) + 1 V to VIN = VOUT(TYP) + 6 V.
EMITTER
RIPPLE REJECTION RATIO (RR) Ripple rejection is the ability of the regulator to attenuate the ripple content of the input voltage at the output. It is specified with 100 mVrms, 400 Hz superimposed on the input voltage, where VIN = VOUT(TYP) + 1.5 V. The output decoupling capacitor is set to 10 F, the noise bypass capacitor is set to 0.1 F, and the load current is set to 30 mA. Ripple rejection is the ratio of the ripple content of the output vs. the input and is expressed in dB. STANDBY CURRENT (ISTBY) Standby current is the current which flows into the regulator when the output is turned off by the control function (VCONT = 0 V). It is measured with VIN = 8 V (9 V for the 8 V output device). REMOTE SENSING (VSENSE) The VSENSE pin is the output voltage sensing pin. If the voltage drop to the load caused by the PCB etch resistance cannot be disregarded, the voltage drop can be compensated by connecting the VSENSE pin as shown below.
COLLECTOR
EXTERNAL TRANSISTOR
VOUT BASE
LOAD REGULATION (Load Reg) Load regulation is the ability of the regulator to maintain a constant output voltage as the load current changes. It is a pulsed measurement to minimize temperature effects. Load regulation depends on the external transistor. QUIESCENT CURRENT (IQ) The quiescent current is the current which flows through the ground terminal under no load conditions (IOUT = 0 mA) and excludes the control pin current. The length of the VSENSE etch should be limited to 30 cm (11.8 in.) maximum.
RIPK CL
TK732XX
GROUND CURRENT (IGND) Ground current is the current which flows through the ground pin(s). It is defined as IIN - IOUT, excluding control current. January 1999 TOKO, Inc. Page 9
TK732xx
DEFINITION AND EXPLANATION OF TECHNICAL TERMS (CONT.)
SENSOR CIRCUITS Overcurrent Sensor The overcurrent sensor protects the device if the output is shorted to ground. Thermal Sensor The thermal sensor protects the device if the junction temperature exceeds the safe value (Tj = 150 C). This temperature rise can be caused by extreme heat, excessive power dissipation caused by large output voltage drops, or excessive output current. The regulator will shut off when the temperature exceeds the safe value. As the junction temperature decreases, the regulator will begin to operate again. Under sustained fault conditions, the regulator output will oscillate as the device turns off then resets. Damage may occur to the device under extreme fault conditions. Reverse Voltage Protection Reverse voltage protection prevents damage due to the output voltage being higher than the input voltage. This fault condition can occur when the output capacitor remains charged and the input is reduced to zero, or when an external voltage higher than the input voltage is applied to the output side. PACKAGE POWER DISSIPATION (PD) This is the power dissipation level at which the thermal sensor is activated. The IC contains an internal thermal sensor which monitors the junction temperature. When the junction temperature exceeds the monitor threshold of 150 C, the IC is shut down. The junction temperature rises as the difference between the input power (VIN x IIN) and the output power (VOUT x IOUT) increases. The rate of temperature rise is greatly affected by the mounting pad configuration on the PCB, the board material, and the ambient temperature. When the IC mounting has good thermal conductivity, the junction temperature will be low even if the power dissipation is great. When mounted on the recommended mounting pad, the power dissipation of the SOT-23L-8 is increased to 600 mW. For operation at ambient temperatures over 25 C, the power dissipation of the SOT-23L-8 device should be derated at 4.8 mW/C. To determine the power dissipation for shutdown when mounted, attach the device on the actual PCB and Page 10 deliberately increase the output current (or raise the input voltage) until the thermal protection circuit is activated. Calculate the power dissipation of the device by subtracting the output power from the input power. These measurements should allow for the ambient temperature of the PCB. The value obtained from PD /(150 C - TA) is the derating factor. The PCB mounting pad should provide maximum thermal conductivity in order to maintain low device temperatures. As a general rule, the lower the temperature, the better the reliability of the device. The thermal resistance when mounted is expressed as follows:
Tj = 0jA x PD + TA For Toko ICs, the internal limit for junction temperature is 150 C. If the ambient temperature (TA) is 25 C, then: 150 C = 0jA x PD + 25 C 0jA = 125 C / PD PD is the value when the thermal sensor is activated. A simple way to determine PD is to calculate VIN x IIN when the output side is shorted. Input current gradually falls as temperature rises. You should use the value when thermal equilibrium is reached. The range of usable currents can also be found from the graph below.
(mW) PD 3
DPD
6 4 5
25
50
75 TA (C)
150
Procedure: 1) Find PD 2) PD1 is taken to be PD x (Note: It is not necessary to connect
a ceramic capacitor in parallel with an aluminum or tantalum output capacitor. (~0.8 - 0.9)
January 1999 TOKO, Inc.
TK732xx
DEFINITIONS AND TERMS (CONT.)
3) Plot PD1 against 25 C 4) Connect PD1 to the point corresponding to the 150 C with a straight line. 5) In design, take a vertical line from the maximum operating temperature (e.g., 75 C) to the derating curve. 6) Read off the value of PD against the point at which the vertical line intersects the derating curve. This is taken as the maximum power dissipation, DPD. The maximum operating current is: IOUT = (DPD / (VIN(MAX) - VOUT)
750 600 PD (mW) 450 FREE AIR 300 150 0 0 50 TA (C)
GND RIPK GND
APPLICATION INFORMATION
INPUT-OUTPUT CAPACITORS The output capacitor is necessary for stable operation. The regulator may oscillate if the output capacitor is too small or missing. The output capacitor size is determined by load, transient response and external transistor used. Evaluation in the circuit is recommended to ensure performance requirements are satisfied. A minimum of 4.7 F is necessary for stability, with twice that value recommended. The minimum recommended input capacitor is 1 F. Problems do not occur with larger values of capacitance. However, extremely low ESR may result in unstable operation. Thus, the use of large value ceramic capacitors is not recommended on the output. BOARD LAYOUT
MOUNTED AS SHOWN
CONTROL
VOUT
100
150
VIN
SOT-23L-8 POWER DISSIPATION CURVE SOT-23L-8 BOARD LAYOUT
January 1999 TOKO, Inc.
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TK732xx
APPLICATION INFORMATION (CONT.)
PULSE CURRENT LIMIT MODE
CP RP 330 k VIN CN
CONTINUOUS CURRENT LIMIT MODE
CN
VIN CIN CIN
CONT
TK732xx RIPK VCONT RIPK
TK732xx VCONT
EMITTER
BASE CL EXTERNAL TRANSISTOR
GND EMITTER BASE
GND
EXTERNAL TRANSISTOR
CL
COLLECTOR VOUT
COLLECTOR VOUT
The equation for the pulse output current limit is as follows: ISET (mA) = 90 (mV) / RIPK ()
In the continuous current limit mode, the CPULSE pin (pin 3) is directly connected to ground. The output current limit is set by RIPK according to the following equation: ISET (mA) = 100 (mV) / RIPK ()
VOUT
IOUT
During the initial turn-on, charge (surge) current flows to the output capacitor. This IC has a possibility for the current limit to operate and to turn off the output by the charge current of the output capacitor. Therefore, the relationship between CL and CP is set as shown in the graph below:
1000
If the continuous current limit mode is also used for output short circuit protection, the ISET value is set 50% to 100% more than the maximum operating current. The current transistor is selected from the ISET value. The output voltage drops when the output current exceeds the ISET value. However, the output voltage returns to normal once the output current decreases below the ISET value.
100
CL (F)
10
STABLE REGION
1 0.01
0.1 CP (F)
1
10
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January 1999 TOKO, Inc.
TK732xx
APPLICATION INFORMATION (CONT.)
EXTERNAL PNP POWER TRANSISTOR This IC can use any kind of external transistor. The external transistor selection is a function of the load current, Hfe and power dissipation. See following chart:
LOAD CURRENT 0 ~ 180 mA 0 ~ 300 mA 0 ~ 500 mA 0~1A 0~2A 0~3A 0~4A
RECOMMENDED EXTERNAL TRANSISTOR 2SB624, 2SB1115, 2SB799 (NEC), 2SB970 (Matushita) 2SB1115, 2SB799 (NEC) 2SB1114, 2SB1115 (NEC), 2SB1302 (Sanyo), 2SA1203, 2SA1213, 2SA1734 (Toshiba) 2SA1242, 2SA1736 (Toshiba), 2SB1302, 2SA1896 (Sanyo) 2SA1451, 2SA1242 (Toshiba) 2SA1451 (Toshiba), 2SA1645 (NEC) 2SA1451 (Toshiba), 2SB904 (Sanyo), 2SA1645 (NEC)
RECOMMENDED RIPK () 0.33 ~ 0.39 0.22 ~ 0.27 0.12 ~ 0.15 0.056 ~ 0.068 0.033 ~ 0.039 0.022 ~ 0.027 0.012 ~ 0.015
HIGH-SIDE SWITCHING
VDROP
VOLTAGE REGULATOR
VOUT
ON/OFF CONTROL
High-side switching should not be implemented by an external transistor as shown above. This results in additional voltage drop and loss of accuracy.
VIN PRO VCONT TK732xx
VOUT
The high output voltage accuracy and low dropout voltage are maintained when the IC is turned ON/OFF by using the control pin as illustrated above. January 1999 TOKO, Inc. Page 13
TK732xx
APPLICATION INFORMATION (CONT.)
VOLTAGE BACKUP OPERATION (HOLDUP TIME) OUTPUT VOLTAGE ADJUST
VOUT
VOUT
RADJ
VIN VOLTAGE DETECTOR IC VCONT OFF 732xx PRO
VIN TK732xx
1000 pF
RESET CL
VCONT
VSENSE
VCONT
C L becomes the backup power supply when the microprocessor is reset with the voltage detector IC simultaneously with turning OFF the TK732xx. CL provides the holdup time necessary to do an orderly shutdown of the microprocessor. PARALLEL ON/OFF CONTROL OPERATION
When a highly accurate output voltage is necessary, the output can be adjusted. As shown above, higher output resolution can be achieved by putting a resistor (RADJ) in the VSENSE pin in parallel with a 1000 pF capacitor. A value of 2 K provides an adjustment of 50 mV typically. Note: using this technique, the output voltage can only be adjusted higher. BATTERY CHARGER
VIN CONT
VIN
TK732xx
5V 5A
RIPK TK732XX BATTERY
CONT VOLTAGE DETECTOR CIRCUIT OR MICROPROCESSOR VSENSE LOAD
TK11230B R
3V 100 mA
TK11220B
2V 100 mA
CURRENT LIMIT SENSING
EMITTER
BASE VADJ EXTERNAL TRANSISTOR REMOTE SENSING
ON/OFF CONTROL
COLLECTOR
VOUT
CL
The figure above illustrates multiple regulators being controlled by a single ON/OFF control signal. The series resistor R is put in the input line of the low output voltage regulator in order to prevent overdissipation. The voltage dropped across the resistor reduces the large input-tooutput voltage across the regulator, reducing the power dissipation in the device.
Continuous Current Limit Mode: ISET (mA) = 100 (mV) / RIPK ()
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January 1999 TOKO, Inc.
TK732xx
APPLICATION INFORMATION (CONT.)
ISET (Continuous Current Limit Mode) is set to the desired charging current.
CHARGING CHARACTERISTICS
circuit condition, Tr1 is turned "off." This converts the circuit into the pulse current limit mode of operation, reducing the power dissipation in the pass transistor. The transition between the continuous and pulse current limit modes can be controlled by adjusting the operating point of Tr1 by the value of resistor R.
FINISH CHARGE 4.1 V VOUT
SET CHARGING CURRENT
IOUT
LITHIUM ION BATTERY CHARGER WITH OVERDISSIPATION PROTECTION OF EXTERNAL TRANSISTOR (SHORT CIRCUIT MODE)
(RECOMMENDED WITH TK732xxMCLH)
VIN
Tr1 R CONT BATTERY
RIPK
TK732xx
LOAD
EMITTER
BASE
EXTERNAL TRANSISTOR
COLLECTOR
VOUT
CL
During normal operation, Tr1 is turned ON, connecting pin 3 (CPULSE) to ground. This provides the continuous current limit mode for normal operating conditions. During a short January 1999 TOKO, Inc. Page 15
TK732xx
PACKAGE OUTLINE
Marking Information
Product Code C Voltage Code 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 55 70 80 11
SOT-23L-8
0.45
8
5 marking 1.0
Product Code
Voltage Code 1 e 0.8 4
e 0.8
Recommended Mount Pad 0.3 0.1 Cl
+0.3
3.5 - 0.1
(3.4) (0.3)
2.2
0.4
+ 0.3
0.15
0.1
3.3
Dimensions are shown in millimeters Tolerance: x.x = 0.2 mm (unless otherwise specified)
TK73220 TK73221 TK73222 TK73223 TK73224 TK73225 TK73226 TK73227 TK73228 TK73229 TK73230 TK73231 TK73232 TK73233 TK73234 TK73235 TK73236 TK73237 TK73238 TK73239 TK73240 TK73241 TK73242 TK73243 TK73244 TK73245 TK73246 TK73247 TK73248 TK73249 TK73250 TK73255 TK73270 TK73280 TK73211
1.4max
e1 3.0
0 - 0.1
Toko America, Inc. Headquarters 1250 Feehanville Drive, Mount Prospect, Illinois 60056 Tel: (847) 297-0070 Fax: (847) 699-7864
TOKO AMERICA REGIONAL OFFICES
Midwest Regional Office Toko America, Inc. 1250 Feehanville Drive Mount Prospect, IL 60056 Tel: (847) 297-0070 Fax: (847) 699-7864 Western Regional Office Toko America, Inc. 2480 North First Street , Suite 260 San Jose, CA 95131 Tel: (408) 432-8281 Fax: (408) 943-9790 Eastern Regional Office Toko America, Inc. 107 Mill Plain Road Danbury, CT 06811 Tel: (203) 748-6871 Fax: (203) 797-1223 Semiconductor Technical Support Toko Design Center 4755 Forge Road Colorado Springs, CO 80907 Tel: (719) 528-2200 Fax: (719) 528-2375
Visit our Internet site at http://www.tokoam.com
The information furnished by TOKO, Inc. is believed to be accurate and reliable. However, TOKO reserves the right to make changes or improvements in the design, specification or manufacture of its products without further notice. TOKO does not assume any liability arising from the application or use of any product or circuit described herein, nor for any infringements of patents or other rights of third parties which may result from the use of its products. No license is granted by implication or otherwise under any patent or patent rights of TOKO, Inc.
Page 16
(c) 1999 Toko, Inc. All Rights Reserved IC-xxx-TK732xx 0798O0.0K
+0.15 - 0.15
15 max
1.2
January 1999 TOKO, Inc.
Printed in the USA

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