
4-27
TELCOM SEMICONDUCTOR, INC.
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6
5
4
3
1
2
8
REGULATED GaAs FET BIAS SUPPLY
TCM850
TCM851
TCM852
TCM853
FEATURES
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Fixed – 4.1V or Adjustable – 0.5V to – 9V Output
at 5mA
4.5V to 10V Input Voltage Range
Low Output Voltage Ripple
TCM850-852 ..............................................2mVp-p
TCM853......................................................1mVp-p
100kHz Charge Pump Switching Frequency
Optional External Synchronizing Clock
Input (TCM852)
Logic Level Shutdown Mode ................ 0.5
μ
A Typ.
Temperature (TCM850/852/853)
Low Cost, 8-Pin SOIC Package
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APPLICATIONS
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Cellular Phones
Negative Regulated Power Supplies
LCD Bias Contrast Control
Adjustable GaAs FET Bias
Wireless Data Loggers
GENERAL DESCRIPTION
The TCM850/1/2/3 combines an inverting charge pump
and a low noise linear regulator in a single small outline
package. They are ideal for biasing GaAS FETs in cellular
telephone transmitter power amplifiers
All four devices accept a range of input voltages from
4.5V to 10.0V and have – 5mA output current capability. The
TCM850/1/2 have both preset (– 4.1V) and variable (– 0.5V
to –9.0V) output voltages that program with an external
resistor divider. The TCM853 output voltage programs with
an external positive control voltage. The TCM850/1/3 can
be shutdown reducing quiescent current to less than
0.5
μ
A (typ) over temperature, 2
μ
A (typ) for the TCM851.
CHARGE
PUMP
GND
N
FB
(GND to SET
V
OUT
= – 4.1V)
OUT
NEGOUT
SHDN (TCM850)
SHDN (TCM851)
OSC (TCM852)
IN
TCM850
TCM851
TCM852
+
–
– 1.28V
REF
CHARGE
PUMP
GND
CONT
(CONTROL VOLTAGE)
OUT
NEGOUT
SHDN
IN
TCM853
+
–
N
C
1
C
1
C
2
C
3
C
2
C
4
C
4
C
3
C
1
+
C
1
–
C
1
+
C
1
–
ORDERING INFORMATION
Part No.
TCM850COA
TCM850EOA
TCM851COA
TCM851EOA
Package
8-Pin SOIC
8-Pin SOIC
8-Pin SOIC
8-Pin SOIC
Temp. Range
0
°
C to +70
°
C
– 40
°
C to +85
°
C
0
°
C to +70
°
C
– 40
°
C to +85
°
C
0
°
C to +70
°
C
– 40
°
C to +85
°
C
0
°
C to +70
°
C
– 40
°
C to +85
°
C
TCM852COA
TCM852EOA
TCM853COA
TCM853EOA
TCM850EV
8-Pin SOIC
8-Pin SOIC
8-Pin SOIC
8-Pin SOIC
Evaluation Kit for
TCM850/1/2/3
FUNCTIONAL BLOCK DIAGRAM
TC850/1/2/3-3 10/1/96
Figure 1.
EVALUATION
KIT
AVAILABLE