UC1854J UNITRODE, UC1854J Datasheet - Page 5

• Manufacturer Part Number: UC1854J
• Description: UNITRODE
• Manufacturer: UNITRODE

PIN DESCRIPTIONS (cont.)
GT Drv (Pin 16) (gate drive): The output of the PWM is a
totem pole MOSFET gate driver on GT Drv. This output is
internally clamped to 15V so that the IC can be operated
with V
least 5 ohms to prevent interaction between the gate im-
TYPICAL CHARACTERISTICS at T
Open-Loop
ns
Multiplier
Output
degrees
Current Amplifier Gain and Phase vs Frequency
Margin
Phase
Gain
A
dB
CC
700
600
500
400
300
200
100
100
600
500
400
300
200
0
as high as 35V. Use a series gate resistor of at
0
0
120
100
0
-20
Multiplier Output vs Voltage on Mult
80
60
40
20
0
Gate Drive Rise and Fall Time
0.1
100
0.01
Mult Out=0V
200
Mult Out=1
1
Fall Time
Load Capacitance, F
300
0.02
I
AC
Mult Out=2V
10
Frequency
400
V
Rise Time
, A
RMS
kHz
Mult Out=3V
=2V, VA Out=5V
500
0.03
100
600
A
= T
1000
0.04
700
J
= 25 C
800
10000
0.05
5
pedance and the GT Drv output driver that might cause
the GT Drv output to overshoot excessively. Some over-
shoot of the GT Drv output is always expected when driv-
ing a capacitive load.
Open-Loop
Duty
Cycle
degrees
Margin
Phase
Gain
Voltage Amplifier Gain and Phase vs Frequency
dB
100%
95%
90%
85%
80%
75%
70%
1
120
100
Oscillator Frequency vs R
-20
80
60
40
20
Frequency
0
0.1
kHz
Gate Drive Maximum Duty Cycle
1000
100
10
1
1
10
Frequency
R
10
SET
kHz
R
10nF
, k
SET
10
100
, k
5nF
SET
3nF
1000
and C
100pF
500pF
200pF
1nF
2nF
100
UC1854
UC2854
UC3854
10000
T
100