UC3842B/3843B LINEAR INTEGRATED CIRCUIT
UNISONIC TECHNOLOGIES CO., LTD 4 of 10
www.unisonic.com.tw QW-R103-012.E
ELECTRICAL CHARACTERISTICS (Cont.)
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
ERROR AMPLIFIER SECTION
Voltage Feedback Input VFB Vo=2.5V 2.42 2.50 2.58 V
Input Bias Current II
BIAS
V
FB=5.0V -0.1 -2.0 μA
Open Loop Voltage Gain GVO 2 ≤VO≤4V 65 90 dB
Unity Gain Bandwidth GBW TJ =25℃ 0.7 1.0 MHz
Power Supply Rejection Ratio PSRR I2V≤VCC≤25V 60 70 dB
Output Sink Current ISINK V
O=1.1V,VFB =2.7V 2.0 12 mA
Output Source Current ISOURCE V
O=5.0V,VFB=2.3V -0.5 -1.0 mA
Output Voltage Swing High State VOH V
FB=2.3V, RL=15k to GND 5.0 6.2 V
Output Voltage Swing Low State VOL V
FB=2.7V, RL=15k to VREF 0.8 1.1 V
CURRENT SENSE SECTION
Current Sense Input Voltage Gain GV (Note 2, 3) 2.85 3.0 3.15 V/V
Maximum Current Sense Input
Threshold VI(THR) (Note 2) 0.9 1.0 1.1 V
Power Supply Rejection Ratio PSRR 12≤Vcc≤25V (Note 2) 70 dB
Input Bias Current II
BIAS
-2 -10 μA
Propagation Delay tD
IN/OUT
Current Sense Input to Output 150 300 ns
OUTPUT SECTION
Output Low Voltage VOL ISINK=20mA 0.1 0.4 V
ISINK=200mA 1.6 2.2 V
Output High Voltage VOH ISOURCE=20mA 13 13.5 V
ISOURCE=200mA 12 13.4 V
Output Voltage with UVLO
Activated VOL (UVLO) VCC=6.0V,ISINK=1.0mA 0.1 1.1 V
Output Voltage Rise Time tR TJ =25℃,CL=1nF 50 150 ns
Output Voltage Fall Time tF TJ =25℃,CL=1nF 50 150 ns
UNDER-VOLTAGE LOCKOUT SECTION
Startup Threshold VTHR UC3842B 14.5 16 17.5 V
UC3843B 7.8 8.4 9 V
Min. Operating Voltage After
Turn-on(VCC) VCC(MIN) UC3842B 8.5 10 11.5 V
UC3843B 7.0 7.6 8.2 V
PWM SECTION
Duty Cycle MAX DC 94 96 %
MIN 0 %
Total DEVICE
Power Startup Supply Current ICC+IC VCC=6.5V for UC3843B
VCC=14V for UC3842B 0.3 0.5 mA
Power Operating Supply Current ICC+IC Note 1 12 17 mA
Power Supply Zener Voltage VZ I
CC=25mA 30 36 V
Note: 1.
2.
Adject VCC above the Startup threshold before setting to 15V.
This parameter is measured at the latch trip point with VFB=0V.
3. Comparator gain is defined as : GV ΔV Output Compensation
V Current Sense Input