Texas Instruments UC3524ADW, UC3524AN, UC3524ADWTR, UC2524AN, UC2524ADWTR Datasheet

UC1524A

UC2524A

UC3524A

Advanced Regulating Pulse Width Modulators

FEATURES

•Fully Interchangeable with Standard UC1524 Family

•Precision Reference Internally Trimmed to ±1%

•High-Performance Current Limit Function

•Under-Voltage Lockout with Hysteretic Turn-on

•Start-Up Supply Current Less Than 4mA

•Output Current to 200mA

•60V Output Capability

•Wide Common-Mode Input Range for both Error and Current Limit Amplifiers

•PWM Latch Insures Single Pulse per Period

•Double Pulse Suppression Logic

•200ns Shutdown through PWM Latch

•Guaranteed Frequency Accuracy

•Thermal Shutdown Protection

BLOCK DIAGRAM

DESCRIPTION

The UC1524A family of regulating PWM ICs has been designed to retain the same highly versatile architecture of the industry standard UC1524 (SG1524) while offering substantial improvements to many of its limitations. The UC1524A is pin compatible with “non-A” models and in most existing applications can be directly interchanged with no effect on power supply performance. Using the UC1524A, however, frees the designer from many concerns which typically had required additional circuitry to solve.

The UC1524A includes a precise 5V reference trimmed to ±1% accuracy, eliminating the need for potentiometer adjustments; an error amplifier with an input range which includes 5V, eliminating the need for a reference divider; a current sense amplifier useful in either the ground or power supply output lines; and a pair of 60V, 200mA uncommitted transistor switches which greatly enhance output versatility.

An additional feature of the UC1524A is an under-voltage lockout circuit which disables all the internal circuitry, except the reference, until the input voltage has risen to 8V. This holds standby current low until turn-on, greatly simplifying the design of low power, off-line supplies. The turn-on circuit has approximately 600mV of hysteresis for jitter-free activation.

Other product enhancements included in the UC1524A’s design include a PWM latch which insures freedom from multiple pulsing within a period, even in noisy environments, logic to eliminate double pulsing on a single output, a 200ns external shutdown capability, and automatic thermal protection from excessive chip temperature. The oscillator circuit of the UC1524A is usable beyond 500kHz and is now easier to synchronize with an external clock pulse.

The UC1524A is packaged in a hermetic 16-pin DIP and is rated for operation from -55°C to +125°C. The UC2524A and 3524A are available in either ceramic or plastic packages and are rated for operation from -25°C to +85°C and 0°C to 70°C, respectively. Surface mount devices are also available.

VIN	15
OSC	3
RT
	6
CT
	7
COMP
	9
INV. INPUT
	1
N.I. INPUT
	2
CL (+) SENSE
	4
CL (–) SENSE
	5

				+5V
				REFERENCE
	U.V.	POWER TO		REGULATOR
			INTERNAL
	SENSE
		CIRCUITRY
				FLIP
				FLOP
				T
OSC	CLOCK
	RAMP	COMP	R
		S	PWM
		S
	VIN		LATCH
	E/A			1k

200mV	VIN	6V	10k	5.5V
+
	C/L

16 VREF

12 CA

11 EA

13CB

14EB

10 SHUTDOWN

8 GND

UDG-99178

SLUS181A - NOVEMBER 1999

ABSOLUTE MAXIMUM RATINGS

Supply Voltage (VIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V Collector Supply Voltage (VC) . . . . . . . . . . . . . . . . . . . . . . . 60V Output Current (each Output). . . . . . . . . . . . . . . . . . . . . 200mA Maximum Forced Voltage (Pin 9, 10) . . . . . . . . . . . . . -3 to +5V Maximum Forced Current (Pin 9, 10) . . . . . . . . . . . . . . . ±10mA Reference Output Current . . . . . . . . . . . . . . . . . . . . . . . . 50mA Oscillator Charging Current . . . . . . . . . . . . . . . . . . . . . . . . 5mA Power Dissipation at TA = +25°C. . . . . . . . . . . . . . . . . 1000mW Power Dissipation at TC = +25°C . . . . . . . . . . . . . . . . 2000mW Operating Temperature Range . . . . . . . . . . . . -55°C to +125°C Storage Temperature Range. . . . . . . . . . . . . . -65°C to +150°C Lead Temperature, (Soldering, 10 seconds) . . . . . . . . . +300°C

Note: Consult packaging section of Databook for thermal limitations and considerations of package.

DIL-16, SOIC-16 (TOP VIEW)

J or N Package, DW Package

UC1524A

UC2524A

UC3524A

CONNECTION DIAGRAMS

PLCC-20, LCC-20 (TOP VIEW)

Q or L Package

PACKAGE PIN FUNCTION

FUNCTION	PIN
N/C	1
Inv. Input	2
Non-Inv. Input	3
OSC/SYNC	4
C.L. (+) sense	5
N/C	6
C.L. (-) sense	7
RT	8
CT	9
Ground	10
N/C	11
Compensation	12
Shutdown	13
Emitter A	14
Collector A	15
N/C	16
Collector B	17
Emitter B	18
+VIN	19
+5V VREF	20

ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TA = -55°C to +125°C for the UC1524A, -25° to +85°C for the UC2524A, and 0°C to + 70°C for the UC3524A; VIN

= VC = 20V, TA = TJ.

PARAMETER	TEST CONDITIONS	UC1524A / UC2524A				UC3524A				UNITS
		MIN	TYP	MAX	MIN		TYP		MAX
Turn-on Characteristics
Input Voltage	Operating Range after Turn-on	8		40	8				40	V
Turn-on Threshold		6.5	7.5	8.5	6.5		7.5		8.5	V
Turn-on Current	VIN = 6V		2.5	4			2.5		4	mA
Operating Current	VIN = 8 to 40V		5	10			5		10	mA
Turn-on Hysteresis*			0.5				0.5			V
Reference Section
Output Voltage	TJ = 25°C	4.95	5.00	5.05	4.90		5.00		5.10	V
	Over Operating Range	4.9		5.1	4.85				5.15	V
Line Regulation	VIN = 10 to 40V		10	20			10		30	mV
Load Regulation	IL = 0 to 20 mA		20	25			20		35	mV
Temperature Stability*	Over Operating Range*		20	25			20		35	mV
Short Circuit Current	VREF = 0, 25°C ≤ TJ ≤ 125°C		80	100			80		100	mA
Output Noise Voltage*	10Hz ≤ f ≤ 10kHz, TJ =25°C		40				40			Vrms
Long Term Stability*	TJ =125°C, 1000 Hrs.		20	50			20		50	mV

* These parameters are guaranteed by design but not 100% tested in production.

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