CS2844 Datasheet, PDF (3/6 Pages) Cherry Semiconductor Corporation – Current Mode PWM Control Circuit with 50% Max Duty Cycle

Electrical Characteristics: -25≤T_A≤85˚C for CS2844/2845, 0≤T_A≤70˚C for CS3844/3845. V_CC=15V (Note 1); R_T=10kΩ,
C_T=3.3nF for sawtooth mode., unless otherwise stated.
PARAMETER
TEST CONDITIONS
CS2844/CS2845
CS3844/CS3845
MIN TYP MAX MIN TYP MAX UNITS
s Total Standby Current
Start-Up Current
Operating Supply Current
V_CC Zener Voltage
V_FB=V_Sense=0V R_T=10kΩ, C_T=3.3nF
I_CC=25mA
0.5 1.0
11 17
34
0.5 1.0 mA
11 17 mA
34
V
s PWM Section
Maximum Duty Cycle
Minimum Duty Cycle
46 48 50 46 48 50 %
0
0%
PARAMETER
TEST CONDITIONS
s Under-Voltage Lockout Section
Start Threshold
Min. Operating After Turn On
Voltage
CS2844
CS3844
CS2845/CS3845
MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS
15 16 17 14.5 16 17.5 7.8 8.4 9.0 V
9
10 11 8.5 10 11.5 7.0 7.6 8.2 V
Notes: 1. Adjust V_cc above the start threshold before setting at 15V.
2.These parameters, although guaranteed, are not 100% tested in production.
3. Parameter measured at trip point of latch with V_FB=0.
4. Gain defined as:
∆V_COMP
A = _∆VSense ; 0 ≤ V_Sense ≤ 0.8V.
Package Pin Description
PACKAGE PIN #
8L
14L
16L
PDIP/SO SO Narrow SO Wide
1
1
3
2
3
4
3
5
5
4
7
6
PIN SYMBOL
COMP
V_FB
Sense
OSC
5
9
11
Gnd
8
10
Pwr Gnd
6
10
12
V_OUT
11
13
V_CCPwr
7
12
14
V_CC
8
14
15
V_REF
2,4,6,13 1,2,7,8,9,16
NC
FUNCTION
Error amp output, used to compensate error amplifier.
Error amp inverting input.
Noninverting input to Current Sense Comparator.
Oscillator timing network with Capacitor to Ground, resis-
tor to V_REF.
Ground.
Output driver Ground.
Output drive pin.
Output driver positive supply.
Positive power supply.
Output of 5V internal reference.
No Connection.
3