SG2843M Microsemi Analog Mixed Signal Group, SG2843M Datasheet - Page 13
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SG2843M
Manufacturer Part Number
SG2843M
Description
IC PWM CURRENT MODE 8DIP
Manufacturer
Microsemi Analog Mixed Signal Group
Datasheet
1.SG3842M.pdf
(14 pages)
Specifications of SG2843M
Pwm Type
Current Mode
Number Of Outputs
1
Frequency - Max
500kHz
Duty Cycle
100%
Voltage - Supply
8.2 V ~ 30 V
Buck
No
Boost
No
Flyback
Yes
Inverting
No
Doubler
No
Divider
No
Cuk
No
Isolated
Yes
Operating Temperature
-25°C ~ 85°C
Package / Case
8-DIP
Frequency-max
500kHz
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Copyright © 2000
Rev. 1.6a 10/04
From V
Due to inherent instability of current mode converters running above 50% duty cycle, a slope compensation should be added to
either current sense pin or the error amplifier. Figure 23 shows a typical slope compensation technique.
High-peak currents associated with capacitive loads necessitate careful grounding techniques. Timing and bypass capacitors should be
connected to pin 5 in a single point ground. The transistor and 5k potentiometer are used to sample the oscillator waveform and apply
an adjustable ramp to pin 3.
2N222A
R
R
i
d
O
R
C
SLOPE
F
ERROR AMP
ADJUST
8(14)
R
R
4(7)
C
2(3)
1(1)
T
F
T
4.7K
4.7K
1K
ERROR
OSCILLATOR
AMP
5V
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
T Y P I C A L A P P L I C A T I O N C I R C U I T S
100K
2.5V
ADJUST
2N2222
I
SENSE
5K
C
UVLO
U R R E N T
P
FIGURE 24. — OPEN LOOP LABORATORY FIXTURE
R O D U C T I O N
2R
R
5(9)
T
R
FIGURE 23. — SLOPE COMPENSATION
SG1842/43
GOOD LOGIC
- M
1
2
3
4
S
R
1V
V
COMP
V
I
R
SENSE
REF
T
FB
C
O D E
T
SG1842/43
REF
5V
COMP
C.S.
P W M C
C
GROUND
T
OUTPUT
D
LATCH
PWM
V
V
A T A
REF
CC
8
7
6
5
O N T R O L L E R
INTERNAL
BIAS
5V
S
H E E T
0.1µF
SG1842/SG1843 Series
0.1µF
(continued)
7(12)
A
1K
7(11)
6(10)
5(8)
3(5)
V
CC
C
R
V
V
OUTPUT
GROUND
REF
CC
V
IN
Q1
R
S
V
O
13