TK73255 [TOKO]
LOW DROPOUT REGULATOR; 低压差稳压器
| 型号： | TK73255 |
| 厂家： | 
TOKO, INC |
| 描述： | LOW DROPOUT REGULATOR |
| 文件： | 总16页 (文件大小：121K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
TK732xx
LOW DROPOUT REGULATOR
FEATURES
APPLICATIONS
■ Up to 5 A Output Current Capability With External
PNP Transistor
■ Battery Powered Systems
■ Cellular/Cordless Telephones
■ Radio Control Systems
■ Internal Short Circuit Protection
■ Excellent Load Regulation
■ Wireless Communications Systems
■ Portable Instrumentations
■ CMOS/TTL-Compatible On/Off Switch
■ Internal Reverse Bias Current Protection Switch
■ Internal Thermal Shutdown
■ Portable Computers
■ Personal Digital Assistants
■ Local Area Network (LAN) Receivers
■ Lithium Ion Battery Chargers
■ Power Recovery for Microprocessors
■ Broad Operating Voltage Range
■ High Impedance VSENSE Pin (Off Mode)
■ Continuous and Pulsed Current Modes
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.
TK732xx
CONTROL
NOISE
BASE
V
SENSE
BYPASS
01S
C
GND
PULSE
V
I
PK
IN
The current limit characteristics can be configured as
continuous(constantcurrent)orpulsed(cycling).Aninternal
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.
BLOCK DIAGRAM
I
V
SENSE
V
PK
C
BASE
IN
PULSE
ORDERING INFORMATION
TK732
M L
ON/OFF
CIRCUIT
THERMAL
SENSOR
Grade
Voltage Code
Package Code
Tape/Reel Code
Temp. Code
CONTROL
PACKAGE CODE
M: SOT-23L-8
VOLTAGE CODE
TAPE/REEL CODE
L: Tape Left
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
44 = 4.4 V
BANDGAP
REFERENCE
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
45 = 4.5 V
46 = 4.6 V
47 = 4.7 V
48 = 4.8 V
49 = 4.9 V
50 = 5.0 V
55 = 5.5 V *
70 = 7.0 V *
80 = 8.0 V
11 = 11.0 V
GRADE
LEAKAGE
PROTECTION
TEMP. RANGE
C: -30 to 80 C **
None: Standard 2%
I : -40 to 85
C
H: High (Special) ***
* Unavailable with I Rank
** unless Otherwise Specified
*** TK73241MCLH, TK73242MCLH Available Only
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
PARAMETER
Quiescent Current
TEST CONDITIONS
IOUT = 0 mA, Excluding ICONT
VIN = 8 V, Output OFF
MIN
TYP MAX UNITS
IQ
250
360
0.1
µA
µA
ISTBY
Standby Current
VR = 5 V, Excluding External
Transistor, Output OFF
IR(LEAK)
Reverse Bias Leakage (Note 5)
2
50
nA
IOUT
Output Current
Output Voltage
Dropout Voltage
External Transistor Dependent
IOUT = 30 mA, See Table 1
N/A
A
V
V
VOUT
VDROP
External Transistor Dependent
N/A
3.0
10
VIN = VOUT(TYP) + 1 V to
VOUT(TYP) + 6 V (Note 2)
Line Reg Line Regulation
Load reg Load Regulation
20
mV
External Transistor Dependent
1.8 V ≤ VIN ≤ 4 V
mV
mA
mA
mV
mV
IBASE(L)
IBASE(H)
Base Current LOW
Base Current HIGH
15
40
80
70
4.1 V ≤ VIN ≤ 12 V
Continuous Current Limit Mode
Pulse Current Limit Mode
100
90
120
110
VSENSE
Current Limit Detect Voltage
f = 400 Hz, CL = 10 µF,
CN = 0.1 µF, VIN = VOUT(TYP) = 1.5 V,
RR
VNO
Ripple Rejection
Output Noise
57
dB
IOUT = 30 mA, VRIPPLE = 100 mVrms,
(Note 3)
f = 1 kHz, BPF = 400 Hz to 30 kHz,
(Note 3)
0.13
µV/ Hz
IPULSE
CPULSE Pin Terminal Current
Temperature Coefficient
Reference Voltage
(Note 4)
15
25
20
45
µA
ppm/° C
V
∆VOUT /∆T
Vref
1.25
CONTROL TERMINAL SPECIFICATIONS
ICONT
Control Current
VCONT = 1.8 V, Output ON
Output ON
6.5
20
µA
V
VCONT(ON)
Control Voltage (ON)
1.8
VCONT(OFF) Control Voltage (OFF)
Output OFF
0.6
V
Page 2
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)
Full Temp. Range (TA = -40 to +85 °C)
(Applies to "I" Rank Only)
Output Voltage
Voltage Code
VOUT(MIN)
VOUT(MAX)
VOUT(MIN)
VOUT(MAX)
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
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
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
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
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.
Page 3
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
PARAMETER
Quiescent Current
TEST CONDITIONS
IOUT = 0 mA, Excluding ICONT
VIN = 8 V, Output OFF
MIN
TYP MAX
UNITS
µA
IQ
240
300
0.1
ISTBY
Standby Current
µA
VR = 5 V, Excluding External
Transistor, Output OFF
IR(LEAK)
Reverse Bias Leakage (Note 5)
2
50
nA
IOUT
Output Current
Output Voltage
Dropout Voltage
External Transistor Dependent
IOUT = 30 mA, See Table 2
External Transistor Dependent
VIN = VOUT(TYP) + 1 V to
N/A
A
V
V
VOUT
VDROP
N/A
3.0
10
Line Reg Line Regulation
Load reg Load Regulation
20
mV
V
OUT(TYP) + 6 V (Note 2)
External Transistor Dependent
mV
mA
mV
mV
IBASE
Base Current
50
85
75
Continuous Current Limit Mode
Pulse Current Limit Mode
100
90
115
105
VSENSE
Current Limit Detect Voltage
f = 400 Hz, CL = 10 µF,
CN = 0.1 µF, VIN = VOUT(TYP) = 1.5 V,
RR
VNO
Ripple Rejection
Output Noise
57
dB
I
OUT = 30 mA, VRIPPLE = 100 mVrms,
(Note 3)
f = 1 kHz, BPF = 400 Hz to 30 kHz,
(Note 3)
0.13
µV/ Hz
IPULSE
CPULSE Pin Terminal Current
Temperature Coefficient
Reference Voltage
(Note 4)
15
25
20
45
µA
ppm/° C
V
∆VOUT /∆T
Vref
1.25
CONTROL TERMINAL SPECIFICATIONS
ICONT
Control Current
VCONT = 1.8 V, Output ON
Output ON
6.5
20
A
V
V
VCONT(ON)
Control Voltage (ON)
1.8
VCONT(OFF) Control Voltage (OFF)
Output OFF
0.6
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)
Full Temp. Range (TA = -10 to +60 °C)
Output Voltage
Voltage Code
VOUT(MIN)
VOUT(MAX)
VOUT(MIN)
VOUT(MAX)
4.1 V
4.2 V
41
42
4.067 V
4.167 V
4.133 V
4.233 V
4.050 V
4.150 V
4.150 V
4.250 V
January 1999 TOKO, Inc.
Page 5
TK732xx
TEST CIRCUIT
C
C
N
P
R
P
V
IN
C
IN
Note:Transistor: 2SB1115
N = 0.1 µF
C
CONT
R
TK732xx
IPK
CP = 0.1 µF
CL = 4.7 µF
R
P = 330 k
Continuous Current Limit Mode:
SET (mA) = 100 mV / RIPK (Ω)
I
BASE
EMITTER
Pulse Current Limit Mode:
ISET (mA) = 90 mV / RIPK (Ω)
C
L
EXTERNAL
TRANSISTOR
COLLECTOR
V
OUT
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25 °C, external transistor is 2SB1115(NEC), unless otherwise specified.
LINE REGULATION 1
LINE REGULATION 2
LOAD REGULATION
V
TYPICAL
OUT
0
10
(V)
20
0
10
20
0
500
(mA)
1000
V
V
(V)
I
OUT
IN
IN
QUIESCENT CURRENT VS.
OUTPUT VOLTAGE
DROPOUT VOLTAGE VS.
OUTPUT VOLTAGE
GROUND CURRENT VS.
OUTPUT VOLTAGE
5
4
3
2
0
-100
-200
-300
-400
5
4
3
2SB799
V
= 3.0 V
OUT
2SB1115
2SB1114
2SB1302
V
= 5.0 V
OUT
2
1
0
1
0
0
10
(V)
20
0
500
(mA)
1000
0
500
1000
V
I
I
(mA)
IN
OUT
OUT
Page 6
January 1999 TOKO, Inc.
TK732xx
TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)
TA = 25 °C, external transistor is 2SB1115(NEC), unless otherwise specified.
CURRENT LIMIT DETECTOR VOLTAGE
VS. INPUT VOLTAGE
BASE CURRENT DRIVE VS.
INPUT VOLTAGE
REVERSE BIAS CURRENT
(V = 0 TO 6 V)
IN
CONTINUOUS CURRENT
LIMIT MODE
1E-6
1E-9
100
100
50
V
= 0 V
PULSE CURRENT
LIMIT MODE
IN
V
= 6 V
IN
50
V
= 4 V
IN
= 2 V
V
IN
1E-12
0
5
10
15
0
5
10
15
0
5
10
V
(V)
V
(V)
V
(V)
REV
IN
IN
QUIESCENT CURRENT VS.
INPUT VOLTAGE (OFF MODE)
RIPPLE REJECTION
0
-20
-40
-60
C
= NONE
N
V
IN
V
OUT
732xx
1E-6
1E-9
V
CONT
R
C
L
4.7 µF
C
= 0.01 µF
N
C
N
CONT
C
= 0.1 µF
N
RIPPLE REJECTION CIRCUIT
-80
-100
1E-12
0.01
0.1
1
10
100
0
10
20
f (kHz)
V
(V)
IN
CONTROL CURRENT VS.
TEMPERATURE
CONTROL VOLTAGE (OUTPUT ON
POINT) VS. TEMPERATURE
OUTPUT VOLTAGE VARIATION VS.
TEMPERATURE
50
2.0
1.0
50
R
= 0 Ω
CONT
V
= 5 V
CONT
40
30
20
30
10
V
TYPICAL
OUT
-10
V
= 2 V
CONT
10
0
-30
-50
-50
0
50
100
-50
0
50
100
-50
0
50
100
T
(°C)
T
A
(°C)
T (°C)
A
A
January 1999 TOKO, Inc.
Page 7
TK732xx
TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)
TA = 25 °C, external transistor is 2SB1115(NEC), unless otherwise specified.
CONTROL PIN VOLTAGE VS
CONTROL CURRENT
.
ON/OFF TRANSIENT
ON/OFF STEP RESPONSE
5000
1000
50
40
30
20
V
OUT
C
= 100 µF
L
ON/OFF CONTROL
R
= 0 k
CONT
C
= 4.7 µF
L
R
= 100 k
CONT
C
= 4.7 µF OR 10 µF
C
= 22 µF
L
L
C
= 4.7 µF
= NONE
L
C
N
100
10
10
0
R
= 200 k
CONT
50
(µA)
-50
0
100
0.001
0.01
0.1
10
0
10
20
30
I
C
(µF)
N
TIME (µs)
CONT
LINE CURRENT STEP RESPONSE
LOAD CURRENT STEP RESPONSE
V
+ 2 V
OUT
I
= 0 TO 300 mA
V
+ 1 V
OUT
OUT
C
N
= NONE
C
= 47 OR 100 µF
L
C
N
= 0.1 µF
C
= 22 µF
L
C
= 10 µF
L
I
= 50 mA
OUT
C
= 4.7 µF
5
L
0
10
TIME (µs)
15
20
TIME (µs)
Page 8
January 1999 TOKO, Inc.
TK732xx
DEFINITION AND EXPLANATION OF TECHNICAL TERMS
OUTPUT VOLTAGE (VOUT
)
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 µF, the noise bypass
capacitor is set to 0.1 µF, 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.
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.
STANDBY CURRENT (ISTBY
)
Standbycurrentisthecurrentwhichflowsintotheregulator
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).
BASE CONTROL CURRENT (IBASE
)
The base control current is the drive current for the base of
the external transistor.
REMOTE SENSING (VSENSE
)
OUTPUT CURRENT (IOUT
)
The VSENSE pin is the output voltage sensing pin. If the
voltagedroptotheloadcausedbythePCBetchresistance
cannot be disregarded, the voltage drop can be
compensated by connecting the VSENSE pin as shown
below.
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.
COLLECTOR
EXTERNAL
TRANSISTOR
V
OUT
EMITTER
BASE
LOAD REGULATION (Load Reg)
C
L
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.
R
IPK
TK732XX
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.
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
deliberately increase the output current (or raise the input
voltage) until the thermal protection circuit is activated.
Calculatethepowerdissipationofthedevicebysubtracting
the output power from the input power. These
measurements should allow for the ambient temperature
ofthePCB. ThevalueobtainedfromPD /(150°C-TA)isthe
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
thermalresistancewhenmountedisexpressedasfollows:
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
temperaturerisecanbecausedbyextremeheat,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.
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
Reverse Voltage Protection
Reverse voltage protection prevents damage due to the
output voltage being higher than the input voltage. This
faultconditioncanoccurwhentheoutputcapacitorremains
charged and the input is reduced to zero, or when an
external voltage higher than the input voltage is applied to
the output side.
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.
PACKAGE POWER DISSIPATION (PD)
The range of usable currents can also be found from the
graph below.
This is the power dissipation level at which the thermal
sensor is activated. The IC contains an internal thermal
sensorwhichmonitorsthejunctiontemperature. Whenthe
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
theSOT-23L-8deviceshouldbederatedat4.8mW/°C. To
determine the power dissipation for shutdown when
mounted, attach the device on the actual PCB and
(mW)
3
P
D
6
D
PD
4
5
25
50
75
(°C)
150
T
A
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)
Page 10
January 1999 TOKO, Inc.
TK732xx
DEFINITIONS AND TERMS (CONT.)
APPLICATION INFORMATION
3) Plot PD1 against 25 °C
INPUT-OUTPUT CAPACITORS
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.
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
µF is necessary for stability, with twice that value
recommended. The minimum recommended input
capacitor is 1 µF. Problems do not occur with larger values
ofcapacitance. However, extremelylowESRmayresultin
unstable operation. Thus, the use of large value ceramic
capacitors is not recommended on the output.
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
MOUNTED AS
SHOWN
BOARD LAYOUT
600
450
300
FREE AIR
GND
CONTROL
150
0
V
OUT
V
IN
0
50
100
150
T
(°C)
A
R
GND
IPK
SOT-23L-8 POWER DISSIPATION CURVE
SOT-23L-8 BOARD LAYOUT
January 1999 TOKO, Inc.
Page 11
TK732xx
APPLICATION INFORMATION (CONT.)
PULSE CURRENT LIMIT MODE
CONTINUOUS CURRENT LIMIT MODE
C
C
N
P
C
N
R
P
330 k
V
IN
V
CONT
IN
C
C
IN
IN
TK732xx
TK732xx
R
R
IPK
IPK
V
V
CONT
CONT
GND
GND
BASE
EMITTER
BASE
EMITTER
C
L
EXTERNAL
TRANSISTOR
C
L
EXTERNAL
TRANSISTOR
COLLECTOR
COLLECTOR
V
OUT
V
OUT
The equation for the pulse output current limit is as follows:
SET (mA) = 90 (mV) / RIPK (Ω)
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:
I
ISET (mA) = 100 (mV) / RIPK (Ω)
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.
V
OUT
I
OUT
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
100
10
STABLE REGION
1
0.01
0.1
1
10
C
(µF)
P
Page 12
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
RECOMMENDED EXTERNAL TRANSISTOR
2SB624, 2SB1115, 2SB799 (NEC), 2SB970 (Matushita)
2SB1115, 2SB799 (NEC)
RECOMMENDED RIPK (Ω)
0.33 ~ 0.39
0 ~ 300 mA
0.22 ~ 0.27
2SB1114, 2SB1115 (NEC), 2SB1302 (Sanyo), 2SA1203,
2SA1213, 2SA1734 (Toshiba)
0 ~ 500 mA
0.12 ~ 0.15
0 ~ 1 A
0 ~ 2 A
0 ~ 3 A
0 ~ 4 A
2SA1242, 2SA1736 (Toshiba), 2SB1302, 2SA1896 (Sanyo)
2SA1451, 2SA1242 (Toshiba)
0.056 ~ 0.068
0.033 ~ 0.039
0.022 ~ 0.027
0.012 ~ 0.015
2SA1451 (Toshiba), 2SA1645 (NEC)
2SA1451 (Toshiba), 2SB904 (Sanyo), 2SA1645 (NEC)
HIGH-SIDE SWITCHING
V
DROP
VOLTAGE
REGULATOR
V
OUT
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.
V
IN
V
OUT
TK732xx
µ PRO
V
CONT
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
V
OUT
V
OUT
R
ADJ
V
IN
1000 pF
VOLTAGE
DETECTOR
IC
µ PRO
732xx
V
IN
TK732xx
V
SENSE
RESET
V
OFF
CONT
C
L
V
CONT
V
CONT
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.
CL becomes the backup power supply when the
microprocessor is reset with the voltage detector IC
simultaneouslywithturningOFFtheTK732xx.CL provides
theholduptimenecessarytodoanorderlyshutdownofthe
microprocessor.
BATTERY CHARGER
PARALLEL ON/OFF CONTROL OPERATION
V
IN
CONT
CONT
5 V
5 A
V
IN
TK732xx
TK11230B
TK11220B
VOLTAGE DETECTOR
CIRCUIT
OR
R
IPK
TK732XX
MICROPROCESSOR
3 V
100 mA
V
SENSE
R
CURRENT
LIMIT
SENSING
LOAD
2 V
100 mA
BASE
EMITTER
V
ADJ
REMOTE
SENSING
EXTERNAL
TRANSISTOR
ON/OFF
CONTROL
COLLECTOR
V
OUT
C
L
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-to-
output voltage across the regulator, reducing the power
dissipation in the device.
Continuous Current Limit Mode:
ISET (mA) = 100 (mV) / RIPK (Ω)
Page 14
January 1999 TOKO, Inc.
TK732xx
APPLICATION INFORMATION (CONT.)
ISET (Continuous Current Limit Mode) is set to the desired
charging current.
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.
CHARGING CHARACTERISTICS
FINISH CHARGE
4.1 V
SET CHARGING CURRENT
I
OUT
LITHIUM ION BATTERY CHARGER WITH
OVERDISSIPATION PROTECTION OF EXTERNAL
TRANSISTOR (SHORT CIRCUIT MODE)
(RECOMMENDED WITH TK732xxMCLH)
V
IN
T
r1
R
CONT
R
IPK
TK732xx
LOAD
BASE
EMITTER
EXTERNAL
TRANSISTOR
COLLECTOR
V
OUT
C
L
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
SOT-23L-8
Product Code
C
Voltage Code
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
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
0.45
8
5
marking
Product Code
Voltage Code
e
0.8
1
4
Recommended Mount Pad
e
0.8
0.3
Çl
0.1
+0.3
3.5 - 0.1
2.2
(3.4)
0.4
+ 0.3
3.3
0.1
Dimensions are shown in millimeters
Tolerance: x.x = ± 0.2 mm (unless otherwise specified)
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
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
Fax: (847) 699-7864
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
January 1999 TOKO, Inc.
© 1999 Toko, Inc.
IC-xxx-TK732xx
0798O0.0K
Printed in the USA
All Rights Reserved
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