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SLUS557B − MARCH 2003 − REVISED APRIL 2004
APPLICATION INFORMATION
Open Loop Laboratory Test Fixture
The following test fixture is useful for exercising many of the UC28025’s functions and measuring their
specifications. As with any wideband circuit, careful ground and by-pass procedures should be followed. The
use of a ground plane is highly recommended.
UC28025
15 V
0.1 µF
4
5
6
CLOCK
RT
VCC 15
VC 13
R
T
3.65 kΩ
T
15 V
10 uF
OSCILLATOR
C
1.0 nF
10 µF
0.1 µF
CT
200 Ω
OUTA 11
OUTB 14
7
3
RAMP
EAOUT
27 kΩ
50 Ω
1N5820
68 kΩ
ERROR
AMPLIFIER
1N5820
4.7 kΩ
4.7 kΩ
10 kΩ
27 kΩ
2
1
8
NI
PGND 12
GND 10
22 kΩ
INV
SS
0.1 µF
10 µF
VREF 16
10 kΩ
9
ILIM/SD
3.3 kΩ
UDG−03051
Figure 20. Laboratory Test Fixture
References
1. 1.5-MHz Current Mode IC Controlled 50−Watt Power Supply, Texas Instruments Application Note Literature
No. SLUA053.
2. The UC3823A,B and UC3825A,B Enhanced Generation of PWM Controllers, Texas Instruments
Application Note Literature No. SLUA125.
15
www.ti.com
TI [ TEXAS INSTRUMENTS ]
