UC1854A
UC2854A, UC2854B
UC3854A, UC3854B
www.ti.com
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.
DESCRIPTION (CONTINUED)
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, RSET 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 × IAC at all times which simplifies the design process and provides foldback
power limiting during brownout and extreme low line conditions.
ORDERING INFORMATION
UVLO
TURN-ON
(V)
UVLO
TURN-OFF
(V)
PART NUMBERS
PDIP-16 SOIC-16
TA
CDIP-16
(V)
PLCC-20
(Q)
(N)
(DW)
16
10.5
16
10
10
10
10
10
10
–
–
–
–
–55°C to 125°C
–40°C to 85°C
0°C to 70°C
UC1854BJ
UC2854AJ
UC2854BJ
–
–
–
–
UC2854AN
UC2854BN
UC2854AN
UC2854BN
UC2854ADW
UC2854BDW
UC2854ADW
UC2854BDW
UC2854AQ
10.5
16
UC2854BQ
–
–
10.5
–
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted)(1)
UCX854A, UCX854B
UNIT
VCC
Supply voltage
GTDRV current
22
V
Continuous
0.5
IGTDRV
A
V
50% duty cycle
1.5
VSENSE, VRMS, ISENSE MOUT
PKLMT
11
Input voltage
5
10
Input current
RSET, IAC, PKLMT, ENA
mA
W
Power dissipation
Junction temperature
Storage temperature
1
TJ
–55 to 150
–65 to 150
300
Tstg
Tsol
°C
Lead temperataure, 1,6 mm (1/16 inch) from case for 10 seconds
(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
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Product Folder Link(s): UC1854A UC2854A, UC2854B UC3854A, UC3854B