Datasheet

3
UC1853
UC2853
UC3853
ELECTRICAL CHARACTERISTICS
Unless otherwise stated, these parameters apply for TA = –55°C to +125°C for the
UC1853; –25°C to +85°C for the 2853; and 0°C to +70°C for the UC3853; VCC =
16V, VFB = 3V, IAC = 100 A, VVCOMP = 3.75V, VICOMP = 3V, TA =TJ.
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Multiplier Section
Output Current – IAC Limited VCC = 11V, VVCOMP = 6V –230 –200 –170 µA
Output Current – Zero IAC = 0µA –2 –0.2 2 µA
Output Current – Power Limited VCC = 12V, V
VCOMP = 5.5V –236 –178 –168 µA
Output Current VCC= 12V, V
VCOMP = 2V –22 µA
VCC= 12V, VVCOMP = 5V –156 µA
VCC= 40V, VVCOMP =2V –2 µA
VCC= 40V, V
VCOMP = 5V –14 µA
Multiplier Gain Constant VCC= 12V, VVCOMP = 5.5V (Note 2) –1.05 –0.9 –0.75 V
–1
Oscillator Section
Oscillator Initial Frequency TA = 25°C 67.5 75 82.5 kHz
Oscillator Frequency Line, Load, Temperature 56 75 94 kHz
Synchronization Frequency Range 100 kHz
Synchronization Pulse Amplitude Pulse slew rate = 100V/ sec (Note 3) 2 V
Output Driver Section
Maximum Output Voltage 0mA load, VCC = 20V 12 15 17.5 V
Output High 0mA load, VCC = 12V, ref. to VCC –2.7 –1.7 V
–50mA load, VCC = 12V, ref. to VCC –3 –2.2 V
Output Low (Device Inactive) Vcc = 0V, 20mA load (Sinking) 0.9 2.0 V
Output Low (Device Active) 50mA load (Sinking) 0.5 1 V
OUT Rise Time 1nF from OUT to GND 55 100 ns
OUT Fall Time 1nF from OUT to GND 35 100 ns
OUT Maximum Duty Cycle V
ICOMP =0V 88 93 %
OVP Comparator Section
Threshold Voltage Volts Above EA Input V 90 150 mV
Hysteresis 80 mV
Note 1:
=
∆
∆
Note 2:
=
•
••
, VCC = 12V.
Note 3.
Synchronization is accomplished with a falling edge of 2V mag-
nitude and 100V/
µ sec slew rate.
(continued)