Datasheet TK73280MILH, TK73280MCLH, TK73280MIL, TK73280MCL, TK73270MILH Datasheet (TOKO)

January 1999 TOKO, Inc. Page 1

TK732xx

C

PULSE

CONTROL

GND

BASE

NOISE

BYPASS

V

SENSE

I

PK

V

IN

TK732xx

01S

FEATURES

■ Up to 5 A Output Current Capability With External

PNP Transistor

■ Internal Short Circuit Protection

■ Excellent Load Regulation

■ CMOS/TTL-Compatible On/Off Switch

■ Internal Reverse Bias Current Protection Switch

■ Internal Thermal Shutdown

■ Broad Operating Voltage Range

■ High Impedance V

SENSE

Pin (Off Mode)

■ Continuous and Pulsed Current Modes

APPLICATIONS

■ 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

VOLTAGE CODE

20 = 2.0 V * 32 = 3.2 V 44 = 4.4 V
21 = 2.1 V * 33 = 3.3 V 45 = 4.5 V
22 = 2.2 V * 34 = 3.4 V 46 = 4.6 V
23 = 2.3 V * 35 = 3.5 V 47 = 4.7 V
24 = 2.4 V 36 = 3.6 V 48 = 4.8 V
25 = 2.5 V 37 = 3.7 V 49 = 4.9 V
26 = 2.6 V 38 = 3.8 V 50 = 5.0 V
27 = 2.7 V 39 = 3.9 V 55 = 5.5 V *
28 = 2.8 V 40 = 4.0 V 70 = 7.0 V *
29 = 2.9 V 41 = 4.1 V 80 = 8.0 V
30 = 3.0 V 42 = 4.2 V 11 = 11.0 V
31 = 3.1 V 43 = 4.3 V

TK732 M L

ORDERING INFORMATION

Tape/Reel Code

TAPE/REEL CODE

L: Tape Left

TEMP. RANGE

C: -30 to 80 C **
I : -40 to 85

C

Temp. Code

Package Code

Voltage Code

Grade

* Unavailable with I Rank
** unless Otherwise Specified
*** TK73241MCLH, TK73242MCLH Available Only

PACKAGE CODE

M: SOT-23L-8

GRADE

None: Standard 2%
H: High (Special) **

*

BLOCK DIAGRAM

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.

CONTROL

NOISE BYPASS

V

IN

THERMAL

SENSOR

ON/OFF

CIRCUIT

BANDGAP

REFERENCE

LEAKAGE

PROTECTION

I

PK C

PULSE

BASEVSENSE

GND

LOW DROPOUT REGULATOR

Page 2 January 1999 TOKO, Inc.

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 = V

OUT(TYP)

+ 1 V, TA = 25 °C, unless otherwise specified.

LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU

I

Q

tnerruCtnecseiuQI

TUO

IgnidulcxE,Am0=

TNOC

052063Aµ

I

YBTS

tnerruCybdnatSV

NI

FFOtuptuO,V8=1.0Aµ

I

)KAEL(R

)5etoN(egakaeLsaiBesreveR

V

R

lanretxEgnidulcxE,V5=

FFOtuptuO,rotsisnarT

205An

I

TUO

tnerruCtuptuOtnednepeDrotsisnarTlanretxEA/NA

V

TUO

egatloVtuptuOI

TUO

1elbaTeeS,Am03=V

V

PORD

egatloVtuoporDtnednepeDrotsisnarTlanretxEA/NV

geReniLnoitalugeReniL

VNIV=

)PYT(TUO

otV1+

V

)PYT(TUO

)2etoN(V6+

0.302Vm

gerdaoLnoitalugeRdaoLtnednepeDrotsisnarTlanretxE01Vm

I

)L(ESAB

WOLtnerruCesaBV8.1 ≤ VNI≤ V451Am

I

)H(ESAB

HGIHtnerruCesaBV1.4 ≤ VNI≤ V2104Am

V

ESNES

egatloVtceteDtimiLtnerruC

edoMtimiLtnerruCsuounitnoC08001021Vm

edoMtimiLtnerruCesluP0709011Vm

RRnoitcejeRelppiR

C,zH004=f

L

,Fµ01=

C

N

V,Fµ1.0=

NI

V=

)PYT(TUO

,V5.1=

I

TUO

V,Am03=

ELPPIR

,smrVm001=

)3etoN(

75Bd

V

ON

esioNtuptuO

,zHk03otzH004=FPB,zHk1=f

)3etoN(

31.0zH/Vµ

I

ESLUP

C

ESLUP

tnerruClanimreTniP)4etoN(515254Aµ

∆V

TUO

/∆T

tneiciffeoCerutarepmeT 02C°/mpp

V

fer

egatloVecnerefeR 52.1V

SNOITACIFICEPSLANIMRETLORTNOC

I

TNOC

tnerruClortnoCV

TNOC

NOtuptuO,V8.1=5.602Aµ

V

)NO(TNOC

)NO(egatloVlortnoCNOtuptuO8.1V

V

)FFO(TNOC

)FFO(egatloVlortnoCFFOtuptuO6.0V

January 1999 TOKO, Inc. Page 3

TK732xx

TK732xx ELECTRICAL CHARACTERISTICS TABLE 1 (STANDARD DEVICES)

Test Conditions: VIN = V

OUT(TYP)

+ 1 V, I

OUT

= 30 mA, TA = 25 °C, unless otherwise specified.

TK732xx ELECTRICAL CHARACTERISTICS (STANDARD DEVICES) CONT.

2.0 V 20 1.940 V 2.060 V

2.1 V 21 2.040 V 2.160 V

2.2 V 22 2.140 V 2.260 V

2.3 V 23 2.240 V 2.360 V

2.4 V 24 2.340 V 2.460 V 2.300 V 2.500 V

2.5 V 25 2.440 V 2.560 V 2.400 V 2.600 V

2.6 V 26 2.540 V 2.660 V 2.500 V 2.700 V

2.7 V 27 2.640 V 2.760 V 2.600 V 2.800 V

2.8 V 28 2.740 V 2.860 V 2.700 V 2.900 V

2.9 V 29 2.840 V 2.960 V 2.800 V 3.000 V

3.0 V 30 2.940 V 3.060 V 2.900 V 3.100 V

3.1 V 31 3.040 V 3.160 V 3.000 V 3.200 V

3.2 V 32 3.140 V 3.260 V 3.095 V 3.305 V

3.3 V 33 3.240 V 3.360 V 3.190 V 3.410 V

3.4 V 34 3.335 V 3.465 V 3.290 V 3.510 V

3.5 V 35 3.435 V 3.565 V 3.385 V 3.615 V

3.6 V 36 3.535 V 3.665 V 3.485 V 3.720 V

3.7 V 37 3.630 V 3.770 V 3.580 V 3.820 V

3.8 V 38 3.725 V 3.875 V 3.675 V 3.925 V

3.9 V 39 3.825 V 3.975 V 3.770 V 4.030 V

4.0 V 40 3.920 V 4.080 V 3.870 V 4.130 V

4.1 V 41 4.020 V 4.180 V 3.965 V 4.235 V

4.2 V 42 4.120 V 4.280 V 4.060 V 4.335 V

4.3 V 43 4.215 V 4.385 V 4.160 V 4.440 V

4.4 V 44 4.315 V 4.485 V 4.255 V 4.545 V

4.5 V 45 4.410 V 4.590 V 4.350 V 4.645 V

4.6 V 46 4.510 V 4.690 V 4.450 V 4.750 V

4.7 V 47 4.605 V 4.795 V 4.545 V 4.850 V

4.8 V 48 4.705 V 4.895 V 4.640 V 4.955 V

4.9 V 49 4.800 V 5.000 V 4.740 V 5.060 V

5.0 V 50 4.900 V 5.100 V 4.835 V 5.165 V

5.5 V 55 5.390 V 5.610 V

7.0 V 70 6.860 V 7.140 V

6.0 V 80 7.840 V 8.160 V 7.745 V 8.265 V

11.0 V 11 10.78 V 11.22 V 10.650 V 11.365 V

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 V

OUT

> 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.

Room Temp. Range (TA = 25 °C) Full Temp. Range (TA = -40 to +85 °C)

(Applies to "I" Rank Only)

Output Voltage Voltage Code V

OUT(MIN)

V

OUT(MAX)

V

OUT(MIN)

V

OUT(MAX)

Page 4 January 1999 TOKO, Inc.

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 = V

OUT(TYP)

+ 1 V, TA = 25 °C, unless otherwise specified.

LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU

I

Q

tnerruCtnecseiuQI

TUO

IgnidulcxE,Am0=

TNOC

042003Aµ

I

YBTS

tnerruCybdnatSV

NI

FFOtuptuO,V8=1.0Aµ

I

)KAEL(R

)5etoN(egakaeLsaiBesreveR

V

R

lanretxEgnidulcxE,V5=

FFOtuptuO,rotsisnarT

205An

I

TUO

tnerruCtuptuOtnednepeDrotsisnarTlanretxEA/NA

V

TUO

egatloVtuptuOI

TUO

2elbaTeeS,Am03=V

V

PORD

egatloVtuoporDtnednepeDrotsisnarTlanretxEA/NV

geReniLnoitalugeReniL

V

NI

V=

)PYT(TUO

otV1+

V

)PYT(TUO

)2etoN(V6+

0.302Vm

gerdaoLnoitalugeRdaoLtnednepeDrotsisnarTlanretxE01Vm

I

ESAB

tnerruCesaB 05Am

V

ESNES

egatloVtceteDtimiLtnerruC

edoMtimiLtnerruCsuounitnoC58001511Vm

edoMtimiLtnerruCesluP5709501Vm

RRnoitcejeRelppiR

C,zH004=f

L

,Fµ01=

C

N

V,Fµ1.0=

NI

V=

)PYT(TUO

,V5.1=

I

TUO

V,Am03=

ELPPIR

,smrVm001=

)3etoN(

75Bd

V

ON

esioNtuptuO

,zHk03otzH004=FPB,zHk1=f

)3etoN(

31.0zH/Vµ

I

ESLUP

C

ESLUP

tnerruClanimreTniP)4etoN(515254Aµ

∆V

TUO

/∆T

tneiciffeoCerutarepmeT 02C°/mpp

V

fer

egatloVecnerefeR 52.1V

SNOITACIFICEPSLANIMRETLORTNOC

I

TNOC

tnerruClortnoCV

TNOC

NOtuptuO,V8.1=5.602A

V

)NO(TNOC

)NO(egatloVlortnoCNOtuptuO8.1V

V

)FFO(TNOC

)FFO(egatloVlortnoCFFOtuptuO6.0V

January 1999 TOKO, Inc. Page 5

TK732xx

TK73241MCLH, TK73242MCLH ELECTRICAL CHARACTERISTICS CONT.

TK73241MCLH, TK73242MCLH ELECTRICAL CHARACTERISTICS TABLE 2

Test Conditions: VIN = V

OUT(TYP)

+ 1 V, I

OUT

= 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 V

OUT(MIN)

V

OUT(MAX)

V

OUT(MIN)

V

OUT(MAX)

4.1 V 41 4.067 V 4.133 V 4.050 V 4.150 V

4.2 V 42 4.167 V 4.233 V 4.150 V 4.250 V

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 V

OUT

> 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.

Page 6 January 1999 TOKO, Inc.

TK732xx

CPC

N

V

IN

R

IPK

CONT

C

L

COLLECTOR

BASE

EMITTER

R

P

C

IN

V

OUT

TK732xx

EXTERNAL

TRANSISTOR

TYPICAL PERFORMANCE CHARACTERISTICS

TA = 25 °C, external transistor is 2SB1115(NEC), unless otherwise specified.

TEST CIRCUIT

V

OUT

(

5

0

m

V/

DIV)

LINE REGULATION 1

VIN (V)

0 10 20

V

OUT

(10

m

V/

DIV)

LINE REGULATION 2

VIN (V)

0 10 20

V

OUT

(

5 m

V/

DIV)

LOAD REGULATION

I

OUT

(mA)

0 500 1000

V

OUT

TYPICAL

I

Q

(

m

A)

3

5

QUIESCENT CURRENT

VS.

OUTPUT VOLTAGE

VIN (V)

1

0 10 20

4

2

0

V

OUT

= 3.0 V

V

OUT

= 5.0 V

V

DROP

(

m

V)

-200

0

DROPOUT VOLTAGE

VS.

OUTPUT VOLTAGE

I

OUT

(mA)

-400

0 500 1000

-100

-300

2SB799

2SB1115

2SB1114

2SB1302

I

GND

(

m

A)

3

5

GROUND CURRENT

VS.

OUTPUT VOLTAGE

I

OUT

(mA)

1

0 500 1000

4

2

0

Note:Transistor: 2SB1115

CN = 0.1 µF
CP = 0.1 µF
CL = 4.7 µF
RP = 330 k
Continuous Current Limit Mode:
I

SET

(mA) = 100 mV / R

IPK

(Ω)
Pulse Current Limit Mode:
I

SET

(mA) = 90 mV / R

IPK

(Ω)

January 1999 TOKO, Inc. Page 7

TK732xx

∆

V

(

m

V)

100

CURRENT LIMIT DETECTOR VOLTAGE

VS. INPUT VOLTAGE

VIN (V)

50

0 5 10 15

CONTINUOUS CURRENT

LIMIT MODE

PULSE CURRENT

LIMIT MODE

I

B

(

m

A)

100

BASE CURRENT DRIVE

VS.

INPUT VOLTAGE

VIN (V)

50

0 5 10 15

I

REV

(A)

1E-6

REVERSE BIAS CURRENT

(VIN = 0 TO 6 V)

V

REV

(V)

1E-12

0 5 10

1E-9

VIN = 0 V

VIN = 6 V

VIN = 4 V

VIN = 2 V

I

Q

(A)

1E-6

QUIESCENT CURRENT

VS.

INPUT VOLTAGE (OFF MODE)

VIN (V)

1E-12

0 10 20

1E-9

RIPPLE REJECTION

0.01 0.1 1 10 100
f (kHz)

-80

RR (dB)

-20

-60

-40

0

-100

CN = 0.01 µF

CN = 0.1 µF

CN = NONE

I

CONT

(

µ

A)

50

CONTROL CURRENT

VS.

TEMPERATURE

TA (°C)

-50 0 50 100

20

40

30

10

0

V

CONT

= 5 V

V

CONT

= 2 V

V

OUT

(mV)

50

OUTPUT VOLTAGE VARIATION

VS.

TEMPERATURE

TA (°C)

-50 0 50 100

-10

30

10

-30

-50

V

OUT

TYPICAL

732xx

C

L

4.7 µF

V

OUT

V

IN

R

CONT

V

CONT

C

N

RIPPLE REJECTION CIRCUIT

V

CONT

(V)

2.0

CONTROL VOLTAGE (OUTPUT ON

POINT) VS. TEMPERATURE

TA (°C)

-50 0 50 100

1.0

R

CONT

= 0 Ω

TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)

TA = 25 °C, external transistor is 2SB1115(NEC), unless otherwise specified.

Page 8 January 1999 TOKO, Inc.

TK732xx

V

CONT

(V)

50

CONTROL PIN VOLTAGE

VS

.

CONTROL CURRENT

I

CONT

(µA)

-50 0 50 100

20

40

30

10

0

R

CONT

= 0 k

R

CONT

= 200 k

V

OUT

R

CONT

= 100 k

V

OUT

ON/OFF STEP RESPONSE

TIME (µs)

0 10 20 30

CL = 4.7 µF

CN = NONE

ON/OFF CONTROL

V

OUT

(200

m

V/

DIV)

LOAD CURRENT STEP RESPONSE

TIME (µs)

0 5 10 15 20

I

OUT

= 0 TO 300 mA

CL = 4.7 µF

CL = 10 µF

CL = 47 OR 100 µF

CL = 22 µF

V

OUT

(20

m

V/

DIV)

LINE CURRENT STEP RESPONSE

TIME (µs)

C

N

= 0.1 µF

I

OUT

= 50 mA

C

N

= NONE

V

OUT

+ 2 V

V

OUT

+ 1 V

V

OUT

V

IN

RISE TIME (µs)

ON/OFF TRANSIENT

CN (µF)

100

5000

10

0.001 0.01 0.1 10

1000

CL = 100 µF

CL = 4.7 µF OR 10 µF

CL = 22 µF

CL = 4.7 µF

TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)

TA = 25 °C, external transistor is 2SB1115(NEC), unless otherwise specified.

January 1999 TOKO, Inc. Page 9

TK732xx

DEFINITION AND EXPLANATION OF TECHNICAL TERMS

OUTPUT VOLTAGE (V

OUT

)

The output voltage is specified with VIN = (V

OUT(TYP)

+ 1 V)

and I

OUT

= 30 mA.

DROPOUT VOLTAGE (V

DROP

)

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 (I

BASE

)

The base control current is the drive current for the base of
the external transistor.

OUTPUT CURRENT (I

OUT

)

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 = V

OUT(TYP)

+ 1 V to VIN = V

OUT(TYP)

+ 6 V.

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 (I

OUT

= 0 mA)

and excludes the control pin current.

GROUND CURRENT (I

GND

)

Ground current is the current which flows through the
ground pin(s). It is defined as I

IN

- I

OUT

, excluding control

current.

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 = V

OUT(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.

STANDBY CURRENT (I

STBY

)

Standby current is the current which flows into the regulator
when the output is turned off by the control function
(V

CONT

= 0 V). It is measured with VIN = 8 V (9 V for the

8 V output device).

REMOTE SENSING (V

SENSE

)

The V

SENSE

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 V

SENSE

pin as shown

below.

The length of the V

SENSE

etch should be limited to 30 cm

(11.8 in.) maximum.

COLLECTOR

V

OUT

EMITTER BASE

R

IPK

C

L

EXTERNAL

TRANSISTOR

TK732XX

Page 10 January 1999 TOKO, Inc.

TK732xx

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 + T

A

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 / P

D

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.

Procedure:

1) Find P

D

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)

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 (V

OUT

x I

OUT

) 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

DEFINITION AND EXPLANATION OF TECHNICAL TERMS (CONT.)

P

D

D

PD

25 50 75 150

(mW)

TA (°C)

3

6

5

4

January 1999 TOKO, Inc. Page 11

TK732xx

3) Plot PD1 against 25 °C

4) Connect P

D1

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:

I

OUT

= (D

PD

/ (V

IN(MAX) - VOUT

)

SOT-23L-8 POWER DISSIPATION CURVE

V

IN

R

IPK

CONTROL

GND

GND

V

OUT

DEFINITIONS AND TERMS (CONT.)

0 50 100 150

TA (°C)

P

D

(mW)

0

450

750

150

300

600

MOUNTED AS

SHOWN

FREE AIR

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
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
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

SOT-23L-8 BOARD LAYOUT

APPLICATION INFORMATION

Page 12 January 1999 TOKO, Inc.

TK732xx

PULSE CURRENT LIMIT MODE

The equation for the pulse output current limit is as follows:

I

SET

(mA) = 90 (mV) / R

IPK

(Ω)

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:

C

P

C

N

V

IN

COLLECTOR

BASE

EMITTER

R

P

330 k

V

OUT

V

CONT

C

L

R

IPK

C

IN

GND

EXTERNAL

TRANSISTOR

TK732xx

APPLICATION INFORMATION (CONT.)

C

L

(µF)

CP (µF)

100

1000

10

100.10.01

STABLE REGION

1

1

V

OUT

I

OUT

CONTINUOUS CURRENT LIMIT MODE

In the continuous current limit mode, the C

PULSE

pin (pin 3)
is directly connected to ground. The output current limit is
set by R

IPK

according to the following equation:

I

SET

(mA) = 100 (mV) / R

IPK

(Ω)

If the continuous current limit mode is also used for output
short circuit protection, the I

SET

value is set 50% to 100%
more than the maximum operating current. The current
transistor is selected from the I

SET

value. The output

voltage drops when the output current exceeds the I

SET

value. However, the output voltage returns to normal once
the output current decreases below the I

SET

value.

C

N

V

IN

COLLECTOR

BASE

EMITTER

V

OUT

V

CONT

C

L

C

IN

CONT

R

IPK

GND

EXTERNAL

TRANSISTOR

TK732xx

January 1999 TOKO, Inc. Page 13

TK732xx

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:

HIGH-SIDE SWITCHING

High-side switching should not be implemented by an external transistor as shown above. This results in additional
voltage drop and loss of accuracy.

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.

LOAD CURRENT RECOMMENDED EXTERNAL TRANSISTOR RECOMMENDED R

IPK

(Ω)

0 ~ 180 mA 2SB624, 2SB1115, 2SB799 (NEC), 2SB970 (Matushita) 0.33 ~ 0.39
0 ~ 300 mA 2SB1115, 2SB799 (NEC) 0.22 ~ 0.27

0 ~ 500 mA

2SB1114, 2SB1115 (NEC), 2SB1302 (Sanyo), 2SA1203,
2SA1213, 2SA1734 (Toshiba)

0.12 ~ 0.15

0 ~ 1 A 2SA1242, 2SA1736 (Toshiba), 2SB1302, 2SA1896 (Sanyo) 0.056 ~ 0.068
0 ~ 2 A 2SA1451, 2SA1242 (Toshiba) 0.033 ~ 0.039
0 ~ 3 A 2SA1451 (Toshiba), 2SA1645 (NEC) 0.022 ~ 0.027
0 ~ 4 A 2SA1451 (Toshiba), 2SB904 (Sanyo), 2SA1645 (NEC) 0.012 ~ 0.015

APPLICATION INFORMATION (CONT.)

ON/OFF

CONTROL

V

OUT

VOLTAGE

REGULATOR

V

DROP

TK732xx

V

OUT

V

IN

V

CONT

µ PRO

Page 14 January 1999 TOKO, Inc.

TK732xx

VOLTAGE BACKUP OPERATION (HOLDUP TIME)

CL 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

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.

APPLICATION INFORMATION (CONT.)

OUTPUT VOLTAGE ADJUST

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 (R

ADJ

) in

the V

SENSE

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

Continuous Current Limit Mode:

I

SET

(mA) = 100 (mV) / R

IPK

(Ω)

732xx

V

OUT

V

IN

V

CONT

OFF

VOLTAGE

DETECTOR

IC

µ PRO

RESET

C

L

2 V

100 mA

TK732xx

5 V
5 A

V

IN

ON/OFF

CONTROL

3 V

100 mA

TK11230B

TK11220B

R

TK732xx

V

OUT

V

IN

V

CONT

V

SENSE

R

ADJ

1000 pF

V

CONT

V

IN

COLLECTOR

BASE

EMITTER

C

L

R

IPK

CONT

V

ADJ

LOAD

VOLTAGE DETECTOR

CIRCUIT

OR

MICROPROCESSOR

BATTERY

REMOTE

SENSING

CURRENT

LIMIT

SENSING

CONT

V

SENSE

V

OUT

EXTERNAL

TRANSISTOR

TK732XX

January 1999 TOKO, Inc. Page 15

TK732xx

I

SET

(Continuous Current Limit Mode) is set to the desired

charging current.

LITHIUM ION BATTERY CHARGER WITH
OVERDISSIPATION PROTECTION OF EXTERNAL
TRANSISTOR (SHORT CIRCUIT MODE)

(RECOMMENDED WITH TK732xxMCLH)

During normal operation, Tr1 is turned ON, connecting pin
3 (C

PULSE

) to ground. This provides the continuous current

limit mode for normal operating conditions. During a short

CHARGING CHARACTERISTICS

I

OUT

FINISH CHARGE

SET CHARGING CURRENT

V

OUT

4.1 V

APPLICATION INFORMATION (CONT.)

V

IN

COLLECTOR

BASE

EMITTER

C

L

R

IPK

T

r1

LOAD

R

CONT

BATTERY

V

OUT

EXTERNAL

TRANSISTOR

TK732xx

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.

Page 16 January 1999 TOKO, Inc.

TK732xx

Marking Information

Product Code C

Voltage Code
TK73220 20
TK73221 21
TK73222 22
TK73223 23
TK73224 24
TK73225 25
TK73226 26
TK73227 27
TK73228 28
TK73229 29
TK73230 30
TK73231 31
TK73232 32
TK73233 33
TK73234 34
TK73235 35
TK73236 36
TK73237 37
TK73238 38
TK73239 39
TK73240 40
TK73241 41
TK73242 42
TK73243 43
TK73244 44
TK73245 45
TK73246 46
TK73247 47
TK73248 48
TK73249 49
TK73250 50
TK73255 55
TK73270 70
TK73280 80
TK73211 11

0.8

0.8

3.3

0.4

2.2

(0.3)

1.2

0.15

0.3

1.0

3.0
e

1

Recommended Mount Pad

5

1

0 - 0.1

15 max

e

4

e

8

0.1

Çl

0.1

0.45

1.4max

(3.4)

3.5

marking

Voltage Code

Product Code

Dimensions are shown in millimeters
Tolerance: x.x = ± 0.2 mm (unless otherwise specified)

+0.3

- 0.1

+0.15

- 0.15
+ 0.3

SOT-23L-8

PACKAGE OUTLINE

Printed in the USA

© 1999 Toko, Inc.
All Rights Reserved

TOKO AMERICA REGIONAL OFFICES

Toko America, Inc. Headquarters
1250 Feehanville Drive, Mount Prospect, Illinois 60056
Tel: [phone] Fax: [phone]

IC-xxx-TK732xx

0798O0.0K

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.

Western Regional Office
Toko America, Inc.
2480 North First Street , Suite 260
San Jose, CA 95131
Tel: [phone]
Fax: [phone]

Midwest Regional Office
Toko America, Inc.
1250 Feehanville Drive
Mount Prospect, IL 60056
Tel: [phone]
Fax: [phone]

Eastern Regional Office
Toko America, Inc.
107 Mill Plain Road
Danbury, CT 06811
Tel: [phone]
Fax: [phone]

Semiconductor Technical Support
Toko Design Center
4755 Forge Road
Colorado Springs, CO 80907
Tel: [phone]
Fax: [phone]