Datasheet

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DESCRIPTION (CONTINUED)
ABSOLUTE MAXIMUM RATINGS
UC1854A
UC2854A, UC2854B
UC3854A, UC3854B
SLUS329E – MONTH 2003 – REVISED JANUARY 2008
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
The UC3854A/B products improve upon the UC3854 by offering a wide bandwidth, low offset current amplifier, a
faster responding and improved accuracy enable comparator, a VREF GOOD comparator, UVLO threshold
options (16 V/10 V for offline, 10.5 V/10 V for startup from an auxiliary 12-V regulator), lower startup supply
current, and an enhanced multiply/divide circuit. New features like the amplifier output clamps, improved amplifier
current sinking capability, and low offset VAC pin reduce the external component count while improving
performance. Improved common mode input range of the multiplier output/current amplifier input allow the
designer greater flexibility in choosing amethod for current sensing. Unlike its predecessor, R
SET
controls only
oscillator charging current and has no effect on clamping the maximum multiplier output current. This current is
now clamped to a maximum of 2 × I
AC
at all times which simplifies the design process and provides foldback
power limiting during brownout and extreme low line conditions.
ORDERING INFORMATION
UVLO UVLO PART NUMBERS
TURN-ON TURN-OFF
T
A
CDIP-16 PDIP-16 SOIC-16 PLCC-20
(V) (V)
(V) (N) (DW) (Q)
16 10 – – – –
– 55 ° C to 125 ° C
10.5 10 UC1854BJ – – –
16 10 UC2854AJ UC2854AN UC2854ADW UC2854AQ
– 40 ° C to 85 ° C
10.5 10 UC2854BJ UC2854BN UC2854BDW UC2854BQ
16 10 – UC2854AN UC2854ADW –
0 ° C to 70 ° C
10.5 10 – UC2854BN UC2854BDW –
over operating free-air temperature range (unless otherwise noted)
(1)
UCX854A, UCX854B UNIT
V
CC
Supply voltage 22 V
Continuous 0.5
I
GTDRV
GTDRV current A
50% duty cycle 1.5
VSENSE, VRMS, ISENSE MOUT 11
Input voltage V
PKLMT 5
Input current RSET, IAC, PKLMT, ENA 10 mA
Power dissipation 1 W
T
J
Junction temperature – 55 to 150
T
stg
Storage temperature – 65 to 150 ° C
T
sol
Lead temperataure, 1,6 mm (1/16 inch) from case for 10 seconds 300
(1) Stresses beyond those listed under absolutemaximum ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating
conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periodsmayaffect device reliability. All voltages
arewith respect to GND. Currents are positive into and negative out of, the specified terminal. ENA input is internally clamped to
approximately 10 V.
2 Submit Documentation Feedback Copyright © 2003 – 2008, Texas Instruments Incorporated
Product Folder Link(s): UC1854A UC2854A, UC2854B UC3854A, UC3854B