鈥?/div>
Optimized for Off-line and DC to DC
Converters
Low Start Up Current (<0.5 mA)
Trimmed Oscillator Discharge Current
D
D
D
D
D
D
D
D
D
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
500 kHz Operation
Low R
O
Error Amp
D PACKAGE
(TOP VIEW)
鈥?Component qualification in accordance with JEDEC and industry
standards to ensure reliable operation over an extended
temperature range. This includes, but is not limited to, Highly
Accelerated Stress Test (HAST) or biased 85/85, temperature
cycle, autoclave or unbiased HAST, electromigration, bond
intermetallic life, and mold compound life. Such qualification
testing should not be viewed as justifying use of this component
beyond specified performance and environmental limits.
COMP
V
FB
I
SENSE
R
T
/C
T
1
2
3
4
8
7
6
5
V
REF
V
CC
OUTPUT
GND
description
The UC1842A/3A/4A/5A family of control ICs is a pin for pin compatible improved version of the UC3842/3/4/5
family. Providing the necessary features to control current mode switched mode power supplies, this family has
the following improved features. Start up current is guaranteed to be less than 0.5 mA. Oscillator discharge is
trimmed to 8.3 mA. During under voltage lockout, the output stage can sink at least 10 mA at less than 1.2 V
for V
CC
over 5 V.
The difference between members of this family are shown in the table below.
PART NUMBER
UC1842A
UC1843A
UC1844A
UC1845A
UVLO ON
16 V
8.5 V
16 V
8.5 V
UVLO OFF
10 V
7.9 V
10 V
7.9 V
MAXIMUM DUTY CYCLE
<100%
<100%
<50%
<50%
ORDERING INFORMATION
鈥?/div>
TA
鈥?5掳C to 125掳C
鈥?5掳C to 125掳C
鈥?5掳C to 125掳C
SOP 鈥?D
SOP 鈥?D
SOP 鈥?D
PACKAGE
鈥?/div>
Tape and reel
Tape and reel
Tape and reel
ORDERABLE
PART NUMBER
UC1842AMDREP
UC1843AMDREP
UC1844AMDREP
TOP-SIDE
MARKING
1842AME
1843AME
1844AME
鈥?5掳C to 125掳C
SOP 鈥?D
Tape and reel
UC1845AMDREP
1845AME
鈥?Package drawings, standard packing quantities, thermal data, symbolization, and PCB design
guidelines are available at www.ti.com/sc/package.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Copyright
铮?/div>
2002 鈥?2003, Texas Instruments Incorporated
POST OFFICE BOX 655303
鈥?/div>
DALLAS, TEXAS 75265
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