UC2843A

Manufacturer Part NumberUC2843A
DescriptionCURRENT MODE PWM CONTROLLER UC2843AHIGH PERFORMANCE CURRENT MODE PWM CONTROLLER UC2843AHIGH PERFORMANCE CURRENT MODE PWM CONTROLLER UC2843ACurrent Mode PWM Controller
ManufacturerTexas Instruments, Inc.
UC2843A datasheet
 


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Current Mode PWM Controller
FEATURES
Optimized for Off-line and DC to DC
Converters
Low Start Up Current (<0.5mA)
Trimmed Oscillator Discharge Current
Automatic Feed Forward Compensation
Pulse-by-Pulse Current Limiting
Enhanced Load Response Characteristics
Under-Voltage Lockout With Hysteresis
Double Pulse Suppression
High Current Totem Pole Output
Internally Trimmed Bandgap Reference
500kHz Operation
Low R
Error Amp
O
BLOCK DIAGRAM
A/B
Note 1:
A = DIL-8 Pin Number. B = SO-14 Pin Number.
Note 2: Toggle flip flop used only in 1844A and 1845A.
SLUS224A - SEPTEMBER 1994 - REVISED APRIL 2002
application
DESCRIPTION
The UC1842A/3A/4A/5A family of control ICs is a pin for pin compati-
ble improved version of the UC3842/3/4/5 family. Providing the nec-
essary features to control current mode switched mode power
supplies, this family has the following improved features. Start up cur-
rent is guaranteed to be less than 0.5mA. Oscillator discharge is
trimmed to 8.3mA. During under voltage lockout, the output stage
can sink at least 10mA at less than 1.2V for V
The difference between members of this family are shown in the table
below.
Part #
UVLO On
UC1842A
16.0V
UC1843A
8.5V
UC1844A
16.0V
UC1845A
8.5V
UC1842A/3A/4A/5A
INFO
UC2842A/3A/4A/5A
available
UC3842A/3A/4A/5A
over 5V.
CC
Maximum Duty
UVLO Off
Cycle
10.0V
<100%
7.9V
<100%
10.0V
<50%
7.9V
<50%

UC2843A Summary of contents