Texas Instruments UC3524N, UC3524DWTR, UC3524J, UC3524DW, UC3524D Datasheet

UC1524

UC2524

UC3524

Advanced Regulating Pulse Width Modulators

FEATURES

•Complete PWM Power Control Circuitry

•Uncommitted Outputs for Single-ended or Push-pull Applications

•Low Standby Current…8mA Typical

•Interchangeable with SG1524, SG2524 and SG3524, Respectively

DESCRIPTION

The UC1524, UC2524 and UC3524 incorporate on a single monolithic chip all the functions required for the construction of regulating power supplies, inverters or switching regulators. They can also be used as the control element for high-power-output applications. The UC1524 family was designed for switching regulators of either polarity, transformer-coupled dc-to-dc converters, transformerless voltage doublers and polarity converter applications employing fixed-frequency, pulse-width modulation techniques. The dual alternating outputs allow either single-ended or push-pull applications. Each device includes an on-chip reference, error amplifier, programmable oscillator, pulse-steering flip-flop, two uncommitted output transistors, a high-gain comparator, and current-limiting and shut-down circuitry. The UC1524 is characterized for operation over the full military temperature range of -55°C to +125°C. The UC2524 and UC3524 are designed for operation from -25°C to +85°C and 0° to +70°C, respectively.

BLOCK DIAGRAM

		VREF	OSC OUT
		16	3
		REFERENCE			+5V TO ALL
VIN	15				INTERNAL
		REGULATOR
			+5V		CIRCUITRY	12	CA
				Q
RT	6	OSC	R	Q
CT	7					11	EA
(RAMP)						13	CB
					+5V
		+5V
INV INPUT	1
		COMPARATOR
NI INPUT	2	E A
						14	EB
GROUND	8		10k			5	–SENSE
(SUBSTRATE)		1k
						C L
						4	+SENSE
		10	9
		SHUTDOWN	COMPENSATION
SLUS180A - NOVEMBER 1999

ABSOLUTE MAXIMUM RATINGS (Note 1)

Supply Voltage, VCC (Notes 2 and 3) . . . . . . . . . . . . . . . . . 40V Collector Output Current. . . . . . . . . . . . . . . . . . . . . . . . . 100mA

Reference Output Current . . . . . . . . . . . . . . . . . . . . . . . . 50mA

Current Through CT Terminal . . . . . . . . . . . . . . . . . . . . . . –5mA Power Dissipation at TA = +25°C (Note 4). . . . . . . . . . 1000mW

Power Dissipation at TC = +25°C (Note 4). . . . . . . . . . 2000mW Operating Junction Temperature Range . . . . –55°C to +150°C Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C

Note 1: Over operating free-air temperature range unless otherwise noted.

Note 2: All voltage values are with respect to the ground terminal, pin 8.

Note 3: The reference regulator may be bypassed for operation from a fixed 5V supply by connecting the VCC and reference output pins both to the supply voltage. In this configuration the maximum supply voltage is 6V.

Note 4: Consult packaging section of databook for thermal limitations and considerations of package.

RECOMMENDED OPERATING CONDITIONS

Supply Voltage, VCC. . . . . . . . . . . . . . . . . . . . . . . . . . 8V to 40V Reference Output Current . . . . . . . . . . . . . . . . . . . . . 0 to 20mA

Current through CT Terminal . . . . . . . . . . . . . –0.03mA to –2mA

Timing Resistor, RT . . . . . . . . . . . . . . . . . . . . . 1.8kΩ to 100kΩ Timing Capacitor, CT . . . . . . . . . . . . . . . . . . . 0.001µF to 0.1µF Operating Ambient Temperature Range

UC1524 . . . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to +125°C UC2524 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –25°C to +85°C UC3524 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C

UC1524

UC2524

UC3524

CONNECTION DIAGRAM

INV INPUT

NON INV

INPUT

OSC OUT

CLSENSE(+)

CLSENSE (–-)

RT

CT

GND

1
EA
2
3
4
CL
5
6
OSC
7
8

REF

REG

S/D

16 VREF

15 VIN

14 EB

13 CB

12 CA

11 EA

10 S/D

9 COMP

ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TA = –55°C to +125°C for the UC1524, –25°C to +85°C for the UC2524, and 0°C to +70°C for the UC3524, VIN = 20V, and f = 20kHz,

TA = TJ.

PARAMETER	TEST CONDITIONS	UC1524/UC2524				UC3524		UNITS
		MIN		MAX	MIN		MAX
Reference Section
Output Voltage		4.8	5.0	5.2	4.6	5.0	5.4	V
Line Regulation	VIN = 8 to 40V		10	20		10	30	mV
Load Regulation	IL = 0 to 20mA		20	50		20	50	mV
Ripple Rejection	f = 120Hz, TJ = 25°C		66			66		dB
Short Circuit Current Limit	VREF = 0, TJ = 25°C		100			100		mA
Temperature Stability	Over Operating Temperature Range		0.3	1		0.3	1	%
Long Term Stability	TJ = 125°C, t = 1000 Hrs.		20			20		mV
Oscillator Section
Maximum Frequency	CT = .001mfd, RT = 2kΩ		300			300		kHz
Initial Accuracy	RT and CT Constant		5			5		%
Voltage Stability	VIN = 8 to 40V, TJ = 25°C			1			1	%
Temperature Stability	Over Operating Temperature Range			5			5	%
Output Amplitude	Pin 3, TJ = 25°C		3.5			3.5		V
Output Pulse Width	CT = .01mfd, TJ = 25°C		0.5			0.5		µs
Error Amplifier Section
Input Offset Voltage	VCM = 2.5V		0.5	5		2	10	mV
Input Bias Current	VCM = 2.5V		2	10		2	10	µA
Open Loop Voltage Gain		72	80		60	80		dB
Common Mode Voltage	TJ = 25°C	1.8		3.4	1.8		3.4	V

2