2
UC1861-1868
UC2861-2868
UC3861-3868
ABSOLUTE MAXIMUM RATINGS
VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22V
Output Current
Source or Sink (Pins 11 & 14) . . . . . . . . . . . . . . . . . . . . . 0.5A
DC Pulse (0.5
µs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5A
Power Ground Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . .
±0.2V
Inputs (Pins 2, 3, 10, & 15) . . . . . . . . . . . . . . . . . . . . –0.4 to 7V
Error Amp Output Current . . . . . . . . . . . . . . . . . . . . . . . .
±2mA
Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1W
Junction Temperature (Operating). . . . . . . . . . . . . . . . . . 150
°C
Lead Temperature (Soldering, 10 seconds) . . . . . . . . . . 300
°C
All voltages are with respect to signal ground and all currents
are positive into the specified terminal. Pin numbers refer to
the J and N packages. Consult Unitrode Integrated Circuits da-
tabook for information regarding thermal specifications and
limitations of packages.
DIL-16, SOIC-16 (Top View)
J or N, DW Packages
CONNNECTION DIAGRAMS
PLCC-20 & LCC-20 (Top View)
Q & L Package
DESCRIPTION (cont.)
UVLO thresholds for the UC1861/62/65/66 are 16.5V
(ON) and 10.5V (OFF), whereas the UC1863/64/67/68
thresholds are 8V (ON) and 7V (OFF). After VCC ex-
ceeds the UVLO threshold, a 5V generator is enabled
which provides bias for the internal circuits and up to
10mA for external usage.
A Fault comparator serves to detect fault conditions and
set a latch while forcing the output drivers low. The Soft-
Ref pin serves three functions: providing soft start, re-
start delay, and the internal system reference.
Each device features dual 1 Amp peak totem pole output
drivers for direct interface to power MOSFETS. The out-
puts
are
programmed
to
alternate
in
the
UC1861/63/65/67 devices.
The UC1862/64/66/68 out-
puts operate in unison alllowing a 2 Amp peak current.
PACKAGE PIN FUNCTION
FUNCTION
PIN
Soft Ref
1
5V
2
NI
3
INV
4
E/A Out
5
Sig Gnd
6
Range
7
RMIN
8
CVCO
9
RC
10
Zero
11
NC
12
NC
13
A Out
14
Pwr Gnd
15
Pwr Gnd
16
VCC
17
B Out
18