Datasheet


   
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SGLS121C − JULY 2002 − REVISED APRIL 2008
8
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
PARAMETER MEASUREMENT INFORMATION
Figure 1
The UCC3800/1/2/3/4/5 oscillator generates a sawtooth waveform
on RC. The rise time is set by the time constant of RT and CT . The
fall time is set by CT and an internal transistor on-resistance of
approximately 125. During the fall time, the output is off and the
maximum duty cycle is reduced below 50% or 100% depending on
the part number. Larger timing capacitors increase the discharge
time and reduce the maximum duty cycle and frequency.
0.2 V
2.5 V
REF
RC
R
T
Oscillator
RQ
S
C
T
8
4
Figure 2
Error Amplifier
Gain/Phase Response
Figure 3
UCC1803/05 V
REF
vs
V
CC
I
L
= 0.5 mA
Figure 4
UCC1800/01/02/04 Oscillator Frequency
vs
R
T
and C
T