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January, 1996 TOKO, Inc.
1-4-96
TK112xxA
VOLTAGE  REGULATOR WITH ON/OFF SWITCH
FEATURES
I
 High Voltage Precision at 
±
 2.4%
I
 Active High On/Off Control
I
 Very Low Dropout Voltage 80 mV at 30 mA
I
 Very Low Noise
I
 Very Small SOT-23L or SOT-89-5 Surface Mount
Packages
I
 Internal Thermal Shutdown
I
 Short Circuit Protection
APPLICATIONS
I
 Battery Powered Systems
I
 Cellular Telephones
I
 Pagers
I
 Personal Communications Equipment
I
 Portable Instrumentation
I
 Portable Consumer Equipment
I
 Radio Control Systems
I
 Toys
I
 Low Voltage Systems
TK112           A 
Voltage Code
Package Code
Tape/Reel Code
TAPE/REEL CODE
BX : Bulk/Bag
TL : Tape Left 
        (SOT-23L)
TB : Tape Bottom
        (SOT-89-5)
PACKAGE CODE
M:  SOT-23L
U:  
SOT-89-5
ORDERING INFORMATION
VOLTAGE CODE
20 = 2.0 V*
21 = 2.1 V
22 = 2.22 V*
25 = 2.5 V*
28 = 2.8 V*
29 = 2.9 V
30 = 3.0 V*
31 = 3.1 V*
33 = 3.3 V*
35 = 3.5 V*
36 = 3.6 V
38 = 3.8 V
40 = 4.0 V*
42 = 4.2 V
45 = 4.5 V*
48 = 4.8 V*
49 = 4.9 V
50 = 5.0 V*
55 = 5.5 V
* Indicates voltage is available in a SOT-89-5 package.
BLOCK DIAGRAM
S
S
S
S
S
S
S
S
S
S
S
V
OUT
GND
+
–
BANDGAP
REFERENCE
THERMAL
PROTECTION
–
+
S
NOISE BYPASS
S
S
S
S
S
S
V
IN
CONTROL
S
S
TK112XXA
P5
1
3
CONTROL
GND
6
4
V
IN
V
OUT
TK112xxA  PO
2
5
GND
NOISE
BYPASS
1
3
6
4
2
5
VOUT
GND
NOISE
BYPASS
GND
CONTROL
VIN
DESCRIPTION
The TK112xxA is a low dropout linear regulator with a built-
in electronic switch.  The internal 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 logic high level.  An
external capacitor can be connected to the noise bypass
pin to lower the output noise level to 30 
μ
Vrms.
An internal PNP pass transistor is used to achieve a low
dropout voltage of 70 mV (typ.) at 30 mA load current.  The
TK112xxA has a very low quiescent current of 180 
μ
A at no
load and 1 mA with a 30 mA load.  The standby current is
typically 100 nA.  The internal thermal shutdown circuitry
limits the junction temperature to below 150 
°
C.  The load
current is internally monitored and the device will shutdown
in the presence of a short circuit or overcurrent condition at
the output.
The TK112xxA is available in either  6 pin SOT-23L or 5 pin
SOT-89-5 surface mount packages.