SG1524B/SG2524B/SG3524B
REGULATING PULSE WIDTH MODULATOR
DESCRIPTION
The SG1524B is a pulse width modulator for switching power supplies
which features improved performance over industry standards like the
SG1524. A direct pin-for-pin replacement for the earlier device, it
combines advanced processing techniques and circuit design to provide
improved reference accuracy, and extended common mode range at the
error amplifier and current limit inputs. A DC-coupled flip-flop eliminates
triggering and glitch problems, and a PWM data latch prevents edge
oscillations. The circuit incorporates true digital shutdown for high speed
response, while an undervoltage lockout circuit prevents spurious outputs
when the supply voltage is too low for stable operation. Full double-pulse
suppression logic insures alternating output pulses when the Shutdown
pin is used for pulse-by-pulse current limiting. The SG1524B is specified
for operation over the full military ambient temperature range of -55°C to
125°C. The SG2524B is characterized for the industrial range of -25°C to
85°C, and the SG3524B is designed for the commercial range of 0°C
to 70°C.
FEATURES
•
•
•
•
•
•
•
•
•
•
•
7V to 40V operation
5V reference trimmed to
±
1%
100Hz to 400KHz oscillator range
Excellent external sync capability
Dual 100mA output transistors
Wide current limit common mode range
DC-coupled toggle flip-flop
PWM data latch
Undervoltage lockout
Full double-pulse suppression logic
60V output collectors
HIGH RELIABILITY FEATURES
- SG1524B
♦
Available to MIL-STD-883 and DESC SMD
♦
Scheduled for MIL-M-38510 QPL listing
♦
Radiation data available
♦
LMI level "S" processing available
DESCRIPTION
V
REF
+V
IN
GROUND
Reference
Regulator
Undervoltage
Lockout
OSC
To Internal
Circuitry
R
T
C
T
Oscillator
COLLECTOR A
S
T
R
INVERTING
Error
NON-INVERTING
+V
IN
+C.L. SENSE
C.L.
-C.L. SENSE
P.W.M.
D
Q
PWM
LATCH
S
Q
Q
Q
Q
TOGGLE
F/F
EMITTER A
COLLECTOR B
MEMORY
F/F
EMITTER B
COMPENSATION
SHUTDOWN
2/00 Rev 1.3 2/00
Copyright
2000
1
11861 Western Avenue
∞
Garden Grove, CA 92841
(714) 898-8121
∞
FAX: (714) 893-2570
L
INFINITY
Microelectronics Inc.
SG1524B/SG2524B/SG3524B
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Input Voltage (+V
IN
) .......................................................... 42V
Collector Voltage ............................................................. 60V
Logic Inputs ..........................................................
-0.3V to 5.5V
Current Limit Sense Inputs .....................................
-0.3V to V
IN
Output Current (each transistor) ................................. 200mA
Reference Load Current ............................................... 50mA
Note 1. Values beyond which damage may occur.
Oscillator Charging Current ..............................................5mA
Operating Junction Temperature
150°C
Hermetic (J, L Packages) ............................................
150°C
Plastic (N, DW Packages) ...........................................
-65°C to 150°C
Storage Temperature Range ............................
Lead Temperature (Soldering, 10 seconds) ...................300°C
THERMAL DATA
J Package:
Thermal Resistance-
Junction to Case
,
θ
JC
.................. 30°C/W
Thermal Resistance-
Junction to Ambient
,
θ
JA
............... 80°C/W
N Package:
Thermal Resistance-
Junction to Case
,
θ
JC
.................. 40°C/W
Thermal Resistance-
Junction to Ambient
,
θ
JA
.............. 65°C/W
DW Package:
Thermal Resistance-
Junction to Case
,
θ
JC
................... 40°C/W
Thermal Resistance-
Junction to Ambient
,
θ
JA
.............. 95°C/W
L Package:
Thermal Resistance-
Junction to Case
,
θ
JC
................... 35°C/W
Thermal Resistance-
Junction to Ambient
,
θ
JA
............ 120°C/W
Note A. Junction Temperature Calculation: T
J
= T
A
+ (P
D
x
θ
JA
).
Note B. The above numbers for
θ
JC
are maximums for the limiting
thermal resistance of the package in a standard mount-
ing configuration. The
θ
JA
numbers are meant to be
guidelines for the thermal performance of the device/pc-
board system. All of the above assume no ambient
airflow.
RECOMMENDED OPERATING CONDITIONS
(Note 2)
Input Voltage (+V
IN
) ................................................ 7V to 40V
Collector Voltage .................................................... 0V to 60V
Error Amp Common Mode Range ....................... 2.3V to V
REF
Current Limit Sense Common Mode Range ...... 0V to V
IN
-2.5V
Output Current (each transistor) .......................... 0 to 100mA
Reference Load Current ........................................ 0 to 20mA
Oscillator Charging Current ............................ 25µA to 1.8mA
Note 2: Range over which the device is functional.
Oscillator Frequency Range ........................ 100Hz to 400KHz
Oscillator Timing Resistor (R
T
) ......................... 2KΩ to 150KΩ
Oscillator Timing Capacitor (C
T
) .......................... 1nF to 0.1µF
Operating Ambient Temperature Range
SG1524B .................................................... -55°C to 125°C
SG2524B ...................................................... -25°C to 85°C
SG3524B ......................................................... 0°C to 70°C
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, these specifications apply over the operating ambient temperatures for SG1524B with -55°C
≤
T
A
≤
125°C, SG2524B with -
25°C
≤
T
A
≤
85°C, SG3524B with 0°C
≤
T
A
≤
70°C, and +V
IN
= 20V. Low duty cycle pulse testing techniques are used which maintains junction and case
temperatures equal to the ambient temperature.)
Parameter
Reference Section
(Note 3)
Output Voltage
Line Regulation
Load Regulation
Temperature Stability
(Note 7)
Total Output Voltage Range
Short Circuit Current
Undervoltage Lockout Section
Threshold Voltage
Note 3. I
L
= 0mA
Test Conditions
T
J
= 25°C
V
IN
= 7V to 40V
I
L
= 0 to 20mA
Over Operating Temperature Range
Over Line, Load and Temperature
V
REF
= 0V
SG1524B/2524B
SG3524B
Units
Min. Typ. Max. Min. Typ. Max.
4.95 5.00 5.05 4.90 5.00 5.10
3
20
3
30
5
30
5
50
15
50
15
50
4.90
5.10 4.80
5.20
25
50 120 25
50 120
4.3
4.5
4.7
4.2
4.5
4.9
V
mV
mV
mV
V
mA
V
2/00 Rev 1.3 2/00
Copyright
2000
2
11861 Western Avenue
∞
Garden Grove, CA 92841
(714) 898-8121
∞
FAX: (714) 893-2570
L
INFINITY
Microelectronics Inc.
Embedded System
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