BICMOS PWM CONTROLLERS
TC25C25
TC35C25
PIN CONFIGURATION (DIP AND SOIC)
–
IN
16
15
14
13
12
11
10
9
–
1
2
3
4
5
6
7
8
V
IN
V
V
1
2
3
4
5
6
7
8
REF
16
15
14
13
12
11
10
9
REF
+
+
IN
+
IN
+
V
IN
IN
SYNC
OUTPUT B
OUTPUT B
SYNC
OSC OUT
V
OSC OUT
V
DD
DD
TC25C25EPE
TC35C25CPE
TC25C25EOE
TC35C25COE
C
T
GND
C
T
GND
R
T
OUTPUT A
SHDN
R
T
OUTPUT A
SHDN
DISCHARGE
SOFT START
DISCHARGE
SOFT START
CMPTR
CMPTR
PIN DESCRIPTION
Pin No.
Symbol
Description
1
2
3
IN–
IN+
Error Amplifier inverting input for output voltage reference input and amplifier gain set.
Error Amplifier, non-inverting input for output voltage feedback to regulate voltage.
SYNC
Input pin for PWM controller oscillator synchronization of two or more controllers from an
external clock output or from another PWM controller oscillator output.
4
5
6
7
OSC OUT
Pin for output of the internal oscillator. This signal can be used as a master oscillator to
sync other oscillators to run at the same timing period.
CT
RT
Pin is the capacitor timing input to set oscillator frequency in conjunction with pin 6 RT timing
resistor.
Pin for timing resistor input to set oscillator frequency by setting the charge current into
capacitor CT of pin 5.
DISCHARGE
Pin for discharging the timing capacitor, CT of pin 5. During discharging time period, PWM
controller output is disabled. This is called dead time. With a resistor between pin 7 and pin 5,
the dead time can be controlled.
8
SOFT START
Pin for soft starting the power supply. A capacitor from this pin to GND pin 12 will limit
duty cycle till capacitor is charged above error amplifier output.
9
CMPTR
SHDN
Pin for compensation of the feedback loop response.
10
Pin for terminating both outputs of pins 11 and 14. This will shutdown the power supply
outputs. A positive input with shutdown threshold of 2.4V is required for shutdown.
11
12
13
14
15
16
OUTPUT A
GND
Pin for output drive of phase A to drive push pull transistor A.
Pin for ground return for all inputs and output signals.
VDD
Pin for power supply input to operate the output drivers A and B.
Pin for output drive of phase B to drive push pull transistor B.
Pin for voltage bias supply input for all PWM controller functions except output drive circuits.
OUTPUT B
V+IN
VREF
Pin is the reference supply output voltage of 4.0 volts that may be used for any voltage
reference purposes such as a reference to control output voltage.
4-114
TELCOM SEMICONDUCTOR, INC.
TELCOM [ TELCOM SEMICONDUCTOR, INC ]
