CS3845B Datasheet, PDF (3/6 Pages) Cherry Semiconductor Corporation – Current Mode PWM Control Circuit with 50% Max Duty Cycle

Electrical Characteristics: continued
PARAMETER
TEST CONDITIONS
MIN
TYP
s Total Standby Current
Start-Up Current
300
Operating Supply Current V_FB=V_Sense=0V R_T=10kΩ, C_T=3.3nF
11
V_CC Zener Voltage
I_CC=25mA
34
MAX UNITS
500
µA
17
mA
V
s PWM Section
Maximum Duty Cycle
Minimum Duty Cycle
46
48
50
%
0
%
s Under-Voltage Lockout Section
Start Threshold
Min. Operating Voltage
After Turn On
Notes:
1. These parameters, although guaranteed, are not 100% test-
ed in production.
2. Parameter measured at trip point of latch with V_FB=0
7.8
8.4
7.0
7.6
9.0
V
8.2
V
3. Gain defined as: A =
∆V_COMP
∆V_Sense
; 0 ≤ V_Sense ≤ 0.8V.
PACKAGE PIN #
8L PDIP & SO 14L SO
1
1
2
3
3
5
4
7
5
9
6
10
7
12
8
14
8
11
2, 4, 6, 13
Package Pin Description
PIN SYMBOL
FUNCTION
COMP
V_FB
Sense
OSC
Gnd
V_OUT
V_CC
V_REF
Pwr Gnd
V_CC Pwr
NC
Error amp output, used to compensate error amplifier
Error amp inverting input
Noninverting input in Current Sense Comparator
Oscillator timing network with Capacitor to Gnd, resistor
to V_REF
Ground
Output drive pin
Positive power supply
Output of 5V internal reference
Output driver Gnd
Output driver positive supply
No Connection
3