SG1842 / 2842 / 3842
C
URRENT
M
ODE
PWM C
ONTROLLER
T
H E
I
N F I N I T E
P
O W E R
O F
I
N N O V A T I O N
P
R O D U C T I O N
D
A T A
S
H E E T
DESCRIPTION
The SG1842/43 family of control IC's provides all lockout, current limiting circuitry and start-up
the necessary features to implement off-line fixed current of less than 1mA. The totem-pole output
frequency, current-mode switching power supplies is optimized to drive the gate of a power
with a minimum number of external components. MOSFET. The output is low in the off state to
Current-mode architecture demonstrates improved provide direct interface to an N channel device.
line regulation, improved load regulation, pulse- The SG1842/43 is specified for operation over
by-pulse current limiting and inherent protection the full military ambient temperature range of -
of the power supply output switch. The bandgap 55°C to 125°C. The SG2842/43 is specified for
reference is trimmed to ±1% over temperature. the industrial range of -25°C to 85°C, and the
Oscillator discharge current is trimmed to less SG3842/43 is designed for the commercial range
than ±10%. The SG1842/43 has under- voltage of 0°C to 70°C.
IMPORTANT:
For the most current data, consult
MICROSEMI’s
website:
http://www.microsemi.com
KEY FEATURES
OPTIMIZED FOR OFF-LINE
CONTROL
LOW START-UP CURRENT (<1mA)
AUTOMATIC FEED FORWARD
COMPENSATION
TRIMMED OSCILLATOR
DISCHARGE CURRENT
PULSE-BY-PULSE CURRENT
LIMITING
ENHANCED LOAD RESPONSE
CHARACTERISTICS
UNDER-VOLTAGE LOCKOUT
WITH 6V HYSTERESIS (SG1842
only)
DOUBLE-PULSE SUPPRESSION
HIGH-CURRENT TOTEM-POLE
OUTPUT (1AMP PEAK)
INTERNALLY TRIMMED BANDGAP
REFERENCE
500KHZ OPERATION
UNDERVOLTAGE LOCKOUT
SG1842 - 16 volts
SG1843 - 8.4 volts
LOW SHOOT-THROUGH
CURRENT <75mA OVER
TEMPERATURE
HIGH RELIABILITY
FEATURES
AVAILABLE TO MIL-STD-883B AND
DESC SMD
SCHEDULED FOR MIL-M38510
QPL LISTING
RADIATION DATA AVAILABLE
LINFINITY LEVEL "S"
PROCESSING AVAILABLE
PRODUCT HIGHLIGHT
R
ST
AC
INPUT
I
ST
V
CC
SG3842
PACKAGE ORDER INFO
T
A
(°C)
0 to 70
-25 to 85
-55 to
125
MIL-
STD/883
DESC
Plastic DIP
M
8-Pin
N
Plastic DIP
14-Pin
Plastic SOIC
DM
8-Pin
Plastic SOIC
D
14-Pin
Y
Ceramic Dip
8-Pin
J
Ceramic DIP
14-Pin
F
Cer Flatpack
10-Pin
L
Ceramic LCC
20-Pin
RoHS / Pb-free Transition DC: 0503
RoHS / Pb-free Transition DC:0440
SG3842M
SG3843M
SG2842M
SG2843M
SG3842N
SG3843N
SG2842N
SG2843N
SG3842DM
SG3843DM
SG2842DM
SG2843DM
SG3842D
SG3843D
SG2842D
SG2843D
SG3842Y
SG3843Y
SG2842Y
SG2843Y
SG1842Y
SG1843Y
SG1842Y/883B
SG1843Y/883B
SG1842Y/DESC
SG3842J
SG3842J
SG2842J
SG2843J
SG1842J
SG1843J
SG1842J/883B
SG1843J/883
SG1842J/DESC
SG1842L
SG1842L
SG1842L/883B
SG1843L/883B
SG1842F/DESC SG1842L/DESC
Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. SG2843DM-TR)
RoHS compliant
Copyright
©
2000
Rev. 1.6a,2005-03-09
L
IN
F
INITY
M
ICROELECTRONICS
I
NC
.
11861 W
ESTERN
A
VENUE
, G
ARDEN
G
ROVE
, CA. 92841, 714-898-8121, F
AX
: 714-893-2570
1
PRODUCT DATABOOK 1996/1997
SG1842/SG1843 Series
C
URRENT
-M
ODE
PWM C
ONTROLLER
P
R O D U C T I O N
D
A T A
S
H E E T
A B S O L U T E M A X I M U M R AT I N G S
(Notes 1 & 2)
PACKAGE PIN OUTS
COMP
V
FB
I
SENSE
R
T
/C
T
1
2
3
4
8
7
6
5
Pb-free / RoHS Peak Package Solder Reflow Temp. (40 second max. exposure)........ 260°C (+0, -5)
Note 1. Exceeding these ratings could cause damage to the device.
Note 2. All voltages are with respect to Pin 5. All currents are positive into the specified
terminal.
Supply Voltage (I
CC
< 30mA) ............................................................... Self Limiting
Supply Voltage (Low Impedance Source) ........................................................ 30V
Output Current (Peak) ....................................................................................... ±1A
Output Current (Continuous) ....................................................................... 350mA
Output Energy (Capacitive Load) ....................................................................... 5µJ
Analog Inputs (Pins 2, 3) ................................................................. -0.3V to +6.3V
Error Amp Output Sink Current ..................................................................... 10mA
Power Dissipation at T
A
= 25°C (DIL-8) ............................................................ 1W
Operating Junction Temperature
Hermetic (J, Y, F, L Packages) ................................................................... 150°C
Plastic (N, M, D, DM Packages) ................................................................ 150°C
Storage Temperature Range .......................................................... -65°C to +150°C
Lead Temperature (Soldering, 10 Seconds) .................................................. 300°C
V
REF
V
CC
OUTPUT
GND
M & Y PACKAGE
(Top View)
M Package: Pb-free / RoHS 100% Matte Tin Lead Finish
COMP
V
FB
I
SENSE
R
T
/C
T
1
2
3
4
8
7
6
5
V
REF
V
CC
OUTPUT
GND
DM PACKAGE
(Top View)
Pb-free / RoHS
100% Matte Tin Lead Finish
COMP
N.C.
V
FB
N.C.
I
SENSE
N.C.
R
T
/C
T
1
2
3
4
5
6
7
14
13
12
11
10
9
8
T H E R M A L D ATA
M PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
N PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
DM PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
D PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
Y PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
J PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
F PACKAGE:
THERMAL RESISTANCE-JUNCTION TO CASE,
θ
JC
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
L PACKAGE:
THERMAL RESISTANCE-JUNCTION TO CASE,
θ
JC
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
35°C/W
120°C/W
3
2
V
REF
N.C.
V
CC
V
C
OUTPUT
GND
PWR GND
95°C/W
65°C/W
165°C/W
120°C/W
130°C/W
80°C/W
80°C/W
145°C/W
D PACKAGE
(Top View)
Pb-free / RoHS 100% Matte Tin Lead Finish
COMP
N.C.
V
FB
N.C.
I
SENSE
N.C.
R
T
/C
T
1
2
3
4
5
6
7
14
13
12
11
10
9
8
V
REF
N.C.
V
CC
V
C
OUTPUT
GROUND
POWER GND
J & N PACKAGE
(Top View)
N Package: Pb-free / RoHS 100% Matte Tin Lead Finish
1. COMP
2. V
FB
3. I
SENSE
4. R
T
/C
T
5. POWER GND
1
2
3
4
5
10
9
8
7
6
10.V
REF
9. V
CC
8. V
C
7. OUTPUT
6. GND
F PACKAGE
(Top View)
1 20 19
Junction Temperature Calculation: T
J
= T
A
+ (P
D
x
θ
JA
).
The
θ
JA
numbers are guidelines for the thermal performance of the device/pc-board
system. All of the above assume no ambient airflow.
4
5
6
7
8
18
17
16
15
14
9 10 11 12 13
1. N.C.
2. COMP
3. N.C.
4. N.C.
5. V
FB
6. N.C.
7. I
SENSE
8. N.C.
9. N.C.
10. R
T
/C
T
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
N.C.
GROUND
N.C.
N.C.
OUTPUT
N.C.
V
CC
N.C.
N.C.
V
REF
L PACKAGE
(Top View)
2
Copyright © 2000
Rev. 1.6a
10/04
PRODUCT DATABOOK 1996/1997
SG1842/SG1843 Series
C
URRENT
-M
ODE
PWM C
ONTROLLER
P
R O D U C T I O N
D
A T A
S
H E E T
R E C O M M E N D E D O P E R AT I N G C O N D I T I O N S
Parameter
Supply Voltage Range
Output Current (Peak)
Output Current (Continuous)
Analog Inputs (Pin 2, Pin 3)
Error Amp Output Sink Current
Oscillator Frequency Range
Oscillator Timing Resistor
Oscillator Timing Capacitor
Operating Ambient Temperature Range:
SG1842/43
SG2842/43
SG3842/43
Note 3. Range over which the device is functional.
(Note 3)
Symbol
Recommended Operating Conditions
Min.
Typ.
Max.
30
±1
200
0
5
0.1
0.52
0.001
-55
-25
0
2.6
500
150
1.0
125
85
70
Units
V
A
mA
V
mA
kHz
KΩ
µF
°C
°C
°C
R
T
C
T
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, these specifications apply over the operating ambient temperatures for SG1842/SG1843 with -55°C
≤
T
A
≤
125°C, SG2842/
SG2843 with -25°C
≤
T
A
≤
85°C, SG3842/SG3843 with 0°C
≤
T
A
≤
70°C, V
CC
= 15V (Note 7), R
T
= 10kΩ, and C
T
= 3.3nF. Low duty cycle pulse testing
techniques are used which maintains junction and case temperatures equal to the ambient temperature.)
Parameter
Reference Section
Output Voltage
Line Regulation
Load Regulation
Temperature Stability (Note 4)
Total Output Variation (Note 4)
Output Noise Voltage (Note 4)
Long Term Stability (Note 4)
Output Short Circuit
Symbol
Test Conditions
SG1842/43
SG2842/43
SG3842/43
Units
Min. Typ. Max. Min. Typ. Max. Min. Typ. Max.
4.95 5.00 5.05 4.95 5.00 5.05 4.90 5.00 5.10
6
20
6
20
6
20
6
25
6
25
6
25
0.2 0.4
0.2 0.4
0.2 0.4
4.90
5.10 4.90
5.10 4.82
5.18
50
50
50
5
25
5
25
5
25
-30 -100 -180 -30 -100 -180 -30 -100 -180
47
52
0.2
5
1.7
8.3
57
1
47
52
0.2
5
1.7
8.4
57
1
47
52
0.2
5
1.7
8.4
57
1
V
mV
mV
mV/°C
V
µV
mV
mA
kHz
%
%
V
mA
mA
V
µA
dB
MHz
dB
mA
mA
V
V
T
J
= 25°C, I
O
= 1mA
12
≤
V
IN
≤
25V
1
≤
I
O
≤
20mA
Line, Load, Temp.
10Hz
≤
f
≤
10kHz, T
J
= 25°C
T
A
= 125°C, 1000hrs
V
N
Oscillator Section
Initial Accuracy
Voltage Stability
Temperature Stability (Note 4)
Amplitude
Discharge Current
T
J
= 25°C
12
≤
V
CC
≤
25V
T
MIN
≤
T
A
≤
T
MAX
V
RT/CT
(Peak to Peak)
T
J
= 25°C
T
MIN
≤
T
A
≤
T
MAX
V
COMP
= 2.5V
A
VOL
PSRR
2
≤
V
O
≤
4V
T
J
= 25°C
12
≤
V
CC
≤
25V
V
VFB
= 2.7V, V
COMP
= 1.1V
V
VFB
= 2.3V, V
COMP
= 5V
V
VFB
= 2.3V, R
L
= 15K to gnd
V
VFB
= 2.7V, R
L
= 15K to V
REF
7.8
7.0
8.8
9.0
7.5
7.2
9.3
9.5
7.5
7.2
9.3
9.5
Error Amp Section
Input Voltage
Input Bias Current
Open Loop Gain
Unity Gain Bandwidth (Note 4)
Power Supply Rejection Ratio
Output Sink Current
Output Source Current
V
OUT
High
V
OUT
Low
2.45 2.50 2.55 2.45 2.50 2.55 2.42 2.50 2.58
-0.3 -1
-0.3
1
-0.3 -2
65
90
65
90
65
90
0.7
1
0.7
1
0.7
1
60
70
60
70
60
70
2
6
2
6
2
6
-0.5 -0.8
-0.5 -0.8
-0.5 -0.8
5
6
5
6
5
6
0.7 1.1
0.7 1.1
0.7 1.1
(Electrical Characteristics continue next page.)
Copyright © 2000
Rev. 1.6a
10/04
3
PRODUCT DATABOOK 1996/1997
SG1842/SG1843 Series
C
URRENT
-M
ODE
PWM C
ONTROLLER
P
R O D U C T I O N
D
A T A
S
H E E T
ELECTRICAL CHARACTERISTICS
Parameter
Current Sense Section
Gain (Notes 5 & 6)
Maximum Input Signal (Note 5)
Power Supply Rejection Ratio (Note 5) PSRR
Input Bias Current
Delay to Output (Note 4)
V
COMP
= 5V
12
≤
V
CC
≤
25V
2.85
0.9
3
1
70
-2
150
0.1
1.5
13.5
13.5
50
50
16
8.4
10
7.6
95
(Cont'd.)
Symbol
Test Conditions
SG1842/43
SG2842/43
SG3842/43
Units
Min. Typ. Max. Min. Typ. Max. Min. Typ. Max.
3.15 2.85
1.1 0.9
-10
300
0.4
2.2
13
12
150
150
17
9.0
11
8.3
100
0
1
17
15
7.8
9
7.0
90
3
1
70
-2
150
0.1
1.5
13.5
13.5
50
50
16
8.4
10
7.6
95
3.15 2.85
1.1 0.9
-10
300
0.4
2.2
13
12
150
150
17
9.0
11
8.2
100
0
14.5
7.8
8.5
7.0
90
3
1
70
-2
150
0.1
1.5
13.5
13.5
50
50
16
8.4
10
7.6
95
3.15
1.1
-10
300
0.4
2.2
V/V
V
dB
µA
ns
V
V
V
V
ns
ns
V
V
V
V
%
%
Output Section
Output Low Level
Output High Level
Rise Time
Fall Time
I
SINK
= 20mA
I
SINK
= 200mA
I
SOURCE
= 20mA
I
SOURCE
= 200mA
T
J
= 25°C, C
L
= 1nF
T
J
= 25°C, C
L
= 1nF
1842
1843
1842
1843
13
12
150
150
17.5
9.0
11.5
8.2
100
0
Under-Voltage Lockout Section
Start Threshold
Min. Operation Voltage After Turn-On
15
7.8
9
7.0
93
PWM Section
Maximum Duty Cycle
Minimum Duty Cycle
Power Consumption Section
Start-Up Current
Operating Supply Current
V
CC
Zener Voltage
V
FB
= V
ISENSE
= 0V
I
CC
= 25mA
0.5
1
0.5
1
mA
11
17
11
17
mA
34
34
V
∆
V
6. Gain defined as: A =
∆
V
COMP
; 0
≤
V
ISENSE
≤
0.8V.
ISENSE
7. Adjust V
CC
above the start threshold before setting at 15V.
0.5
11
34
Notes: 4. These parameters, although guaranteed, are not 100% tested in
production.
5. Parameter measured at trip point of latch with V
VFB
= 0.
4
Copyright © 2000
Rev. 1.6a
10/04
PRODUCT DATABOOK 1996/1997
SG1842/SG1843 Series
C
URRENT
-M
ODE
PWM C
ONTROLLER
P
R O D U C T I O N
D
A T A
S
H E E T
BLOCK DIAGRAM
V
CC
*
34V
UVLO
S/R
5V
REF
GROUND**
16V (1842)
8.4V (1843)
2.5V
6V (1842)
0.8V (1843)
V
REF
5.0V
50mA
INTERNAL
BIAS
V
REF
GOOD LOGIC
R
T
/C
T
OSCILLATOR
V
C
*
OUTPUT
ERROR AMP
2R
R
1V
S
R
CURRENT SENSE
COMPARATOR
PWM
LATCH
POWER GROUND**
V
FB
COMP
CURRENT SENSE
* - V
CC
and V
C
are internally connected for 8 pin packages.
** - POWER GROUND and GROUND are internally connected for 8 pin packages.
Copyright © 2000
Rev. 1.6a
10/04
5
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