P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
UC184xA/284xA/384xA
C U R R E N T M O D E P W M C O N T R O L L E R
P R O D U C T I O N D A T A S H E E T
CHARACTERISTIC CURVES
FIGURE 1. — OSCILLATOR FREQUENCY vs. TIMING
RESISTOR
VREF
8
CT = 1nF
RT
1M
RT/CT
4
5
CT = 2.2nF
CT
100k
GROUND
CT = 4.7nF
10k
0
1.72
RT CT
For RT > 5k, f »
Note: Output drive frequency is half the oscillator frequency for
the UCx844A/5A devices.
300
1.0k
3.0k
10.0k
30.0k
100k
RT - (ohms)
FIGURE 2. — MAXIMUM DUTY CYCLE vs. TIMING RESISTOR
100.0
80.0
60.0
40.0
20.0
0
300
1.0k
3.0k
10.0k
30.0k
100k
RT - (ohms)
Copyright © 1995
Rev. 1.2 12/95
5
MICROSEMI [ Microsemi ]
