Datasheet

4.00
3.98
3.96
3.94
3.92
3.90
3.88
3.86
3.84
3.82
4 4.2 4.4 4.6 4.8
5
5.2 5.4 5.6 5.8 6
V (V)CC
V (V)
REF
0
45
90
135
-20
0
20
40
60
80
10k 10k 100k 1M 10M
Phase (º)
Gain (dB)
Frequency (Hz)
C001
Phase
Gain
_
+
8
REF
4
S
Q
R
_
+
RC
CT
RT
0.2 V
2.5 V
UCC2813-0, UCC2813-1, UCC2813-2, UCC2813-3, UCC2813-4, UCC2813-5
UCC3813-0, UCC3813-1, UCC3813-2, UCC3813-3, UCC3813-4, UCC3813-5
www.ti.com SLUS161D –APRIL 1999–REVISED JUNE 2013
APPLICATION INFORMATION
Figure 1. Oscillator
The UCC3813-0/-1/-2/-3/-4/-5 oscillator generates a sawtooth waveform on RC. The rise time is set by the time
constant of R
T
and C
T
. The fall time is set by CT and an internal transistor on-resistance of approximately 125 Ω.
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.
UCC3813-3 / -5 VREF
vs
ERROR AMPLIFIER GAIN/PHASE RESPONSE VCC; I
LOAD
= 0.5 mA
Figure 2. Figure 3.
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Product Folder Links: UCC2813-0 UCC2813-1 UCC2813-2 UCC2813-3 UCC2813-4 UCC2813-5 UCC3813-0
UCC3813-1 UCC3813-2 UCC3813-3 UCC3813-4 UCC3813-5