Printed Circuit Board Layout Considerations
High speed circuits demand careful attention to layout
and component placement. To assure proper perfor-
mance of the UC1825 follow these rules: 1) Use a ground
plane. 2) Damp or clamp parasitic inductive kick energy
from the gate of driven MOSFETs. Do not allow the out-
put pins to ring below ground. A series gate resistor or a
shunt 1 Amp Schottky diode at the output pin will serve
UC1825
UC2825
UC3825
this purpose. 3) Bypass V
CC
, V
C
, and V
REF
. Use 0.1µF
monolithic ceramic capacitors with low equivalent series
inductance. Allow less than 1 cm of total lead length for
each capacitor between the bypassed pin and the ground
plane. 4) Treat the timing capacitor, CT, like a bypass ca-
pacitor.
Error Amplifier Circuit
Simplified Schematic
Open Loop Frequency Response
Unity Gain Slew Rate
PWM Applications
Conventional (Voltage Mode)
Current-Mode
5
TI [ TEXAS INSTRUMENTS ]
