SG1844/SG1845 Series
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
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
(SG1844 only)
DOUBLE PULSE
SUPPRESSION
HIGH-CURRENT TOTEM-POLE
OUTPUT
INTERNALLY TRIMMED
BANDGAP REFERENCE
500kHz OPERATION
UNDERVOLTAGE LOCKOUT
SG1844 - 16 volts SG1845 - 8.4
volts
LOW SHOOT-THROUGH
CURRENT <75mA OVER
TEMPERATURE
HIGH RELIABILITY
FEATURES
AVAILABLE TO MIL-STD-883B
LINFINITY LEVEL "S"
PROCESSING AVAILABLE
The SG1844/45 family of control ICs
provides all the necessary features to
implement off-line fixed frequency, current-
mode switching power supplies with a
minimum number of external components.
Current-mode architecture demonstrates
improved line regulation, improved load
regulation, pulse-by pulse current limiting
and inherent protection of the power supply
output switch. The bandgap reference is
trimmed to ±1% over temperature. Oscillator
discharge current is trimmed to less than
±10%. The SG1844/45 has undervoltage
lockout, current-limiting circuitry
and start-up current of less than 1mA. The
totem-pole output is optimized to drive the
gate of a power MOSFET. The output is low
in the off state to provide direct interface to
an N-channel device. Both operate up to a
maximum duty cycle range of zero to <50%
due to an internal toggle flip-flop which
blanks the output off every other clock
cycle. The SG1844/45 is specified for
operation over the full military ambient
temperature range of -55°C to 125°C. The
SG2844/45 is specified for the industrial
range of -25°C to 85°C, and the SG3844/45
is designed for the commercial range of 0°C
to 70°C.
IMPORTANT:
For the most current data, consult
MICROSEMI’s
website:
http://www.microsemi.com
PRODUCT HIGHLIGHT
R
ST
AC
INPUT
I
ST
V
CC
SG3844
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 Compliant / Pb-free
Transition DC: 0503
RoHS Compliant / Pb-free
Transition DC:0440
SG3844M
SG3845M
SG2844M
SG2845M
SG3844N
SG3845N
SG28424N
SG2845N
SG3844DM
SG3845DM
SG2844DM
SG2845DM
SG3844D
SG3845D
SG2842D
SG2845D
SG3844Y
SG3845Y
SG2844Y
SG2845Y
SG1844Y
SG1845Y
SG1842Y/883B
SG1845Y/883B
SG1844Y/DESC
SG3844J
SG3845J
SG2844J
SG2845J
SG1844J
SG1845J
SG1844J/883B
SG1845J/883
SG1844J/DESC
SG1844L
SG1845L
SG1844L/883B
SG1845L/883B
SG1844F/DESC SG1844L/DESC
Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LXSG3844N-TR)
Copyright
©
2000
Rev. 1.6c,2006-02-02
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
MICROSEMI [ MICROSEMI CORPORATION ]
