UNITRODE UC1526A, UC2526A, UC3526A Technical data

UC1526A

UC1526A

UC2526A

UC3526A

Regulating Pulse Width Modulator

FEATURES

∙Reduced Supply Current

∙Oscillator Frequency to 600kHz

∙Precision Band-Gap Reference

∙7 to 35V Operation

∙Dual 200mA Source/Sink Outputs

∙Minimum Output Cross-Conduction

∙Double-Pulse Suppression Logic

∙Under-Voltage Lockout

∙Programmable Soft-Start

∙Thermal Shutdown

∙TTL/CMOS Compatible Logic Ports

∙5 Volt Operation (VIN = VC = VREF = 5.0V)

DESCRIPTION

The UC1526A Series are improved-performance pulse-width modulator circuits intended for direct replacement of equivalent non- “A” versions in all applications. Higher frequency operation has been enhanced by several significant improvements including: a more accurate oscillator with less minimum dead time, reduced circuit delays (particularly in current limiting), and an improved output stage with negligible cross-conduction current. Additional improvements include the incorporation of a precision, band-gap reference generator, reduced overall supply current, and the addition of thermal shutdown protection.

Along with these improvements, the UC1526A Series retains the protective features of under-voltage lockout, soft-start, digital current limiting, double pulse suppression logic, and adjustable deadtime. For ease of interfacing, all digital control ports are TTL compatible with active low logic.

Five volt (5V) operation is possible for “logic level” applications by connecting VIN, VC and VREF to a precision 5V input supply. Consult factory for additional information.

BLOCK DIAGRAM

6/93

ABSOLUTE MAXIMUM RATINGS (Note 1, 2)

Input Voltage (+VIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +40V Collector Supply Voltage (+VC) . . . . . . . . . . . . . . . . . . . . . +40V Logic Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +5.5V Analog Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +VIN Source/Sink Load Current (each output) . . . . . . . . . . . . 200mA Reference Load Current. . . . . . . . . . . . . . . . . . . . . . . . . . 50mA Logic Sink Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15mA Power Dissipation at TA = +25°C (Note 2) . . . . . . . . . 1000mW Power Dissipation at TC = +25°C (Note 2) . . . . . . . . . . 3000mW Operating Junction Temperature . . . . . . . . . . . . . . . . . . +150°C Storage Temperature Range . . . . . . . . . . . . . . -65°C to +150°C Lead Temperature (soldering, 10 seconds) . . . . . . . . . . +300°C

Note 1: Values beyond which damage may occur.

Note 2: Consult packaging Section of Databook for thermal limitations and considerations of package.

UC1526A

UC2526A

UC3526A

RECOMMENDED OPERATING CONDITIONS

(Note 3)

Input Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7V to +35V Collector Supply Voltage . . . . . . . . . . . . . . . . . . +4.5V to +35V Sink/Source Load Current (each output) . . . . . . . . 0 to 100mA Reference Load Current . . . . . . . . . . . . . . . . . . . . . . 0 to 20mA Oscillator Frequency Range . . . . . . . . . . . . . . . . 1Hz to 600kHz Oscillator Timing Resistor. . . . . . . . . . . . . . . . . . . 2kΩ to 150kΩ Oscillator Timing Capacitor. . . . . . . . . . . . . . . . . 400pF to 20μF Available Deadtime Range at 40kHz . . . . . . . . . . . . 1% to 50% Operating Ambient Temperature Range

UC1526A. . . . . . . . . . . . . . . . . . . . . . . . . . . . -55°C to +125°C UC2526A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . -25°C to +85°C UC3526A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C

Note 3: Range over which the device is functional and parameter limits are guaranteed.

CONNECTION DIAGRAMS

DIL-18, SOIC-18 (TOP VIEW)

J or N Package, DW Package

	PLCC-20, LCC-20	PACKAGE PIN FUNCTION
	(TOP VIEW)
		FUNCTION	PIN
	Q and L Packages
		N/C	1
		+ERROR	2
		-ERROR	3
		COMP.	4
		CSS	5
		RESET	6
		- CURRENT SENSE	7
		+ CURRENT SENSE	8
		SHUTDOWN	9
		RTIMING	10
		CT	11
		RD	12
		SYNC	13
		OUTPUT A	14
		VC	15
		N/C	16
		GROUND	17
		OUTPUT B	18
		+VIN	19
		VREF	20

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UC1526A

UC2526A

UC3526A ELECTRICAL CHARACTERISTICS: +VIN = 15V, and over operating ambient temperature, unless otherwise specified TA = TJ.

	PARAMETER								TEST CONDITIONS		UC1526A / UC2526A				UC3526A				UNITS
											MIN	TYP	MAX	MIN		TYP	MAX
Reference Section (Note 4)
	Output Voltage						TJ = +25°C				4.95	5.00	5.05	4.90		5.00		5.10	V
	Line Regulation						+VIN = 7 to 35V					2	10			2		15	mV
	Load Regulation						IL = 0 to 20mA					5	20			5		20	mV
	Temperature Stability						Over Operating TJ (Note 5)					15	50			15		50	mV
	Total Output Voltage						Over Recommended Operating				4.90	5.00	5.10	4.85		5.00		5.15	V
	Range						Conditions
Short Circuit Current							VREF = 0V				25	50	100	25		50		100	mA
Under-Voltage Lockout
	RESET		Output Voltage				VREF = 3.8V					0.2	0.4			0.2		0.4	V
							VREF = 4.7V				2.4	4.7		2.4		4.8			V
Oscillator Section (Note 6)
	Initial Accuracy						TJ = +25°C					±3	±8			±3		±8	%
	Voltage Stability						+VIN = 7 to 35V					0.5	1			0.5		1	%
	Temperature Stability						Over Operating TJ (Note 5)					2	6			1		3	%
	Minimum Frequency						RT = 150kW, CT = 20mF (Note 5)						1					1	Hz
	Maximum Frequency						RT = 2kW, CT = 470pF				550			650					kHz
	Sawtooth Peak Voltage						+VIN = 35V					3.0	3.5			3.0		3.5	V
	Sawtooth Valley Voltage						+VIN =7V				0.5	1.0		0.5		1.0			V
							TJ = 25°C, RL = 2.7kW to VREF					1.1				1.1			ms
	SYNC	Pulse Width
Error Amplifier Section (Note 7)
	Input Offset Voltage						RS £ 2kW					2	5			2		10	mV
	Input Bias Current											-350	-1000			-350		-2000	nA
	Input Offset Current											35	100			35		200	nA
	DC Open Loop Gain						RL ³ 10MW				64	72		60		72			dB
HIGH Output Voltage							VPIN 1 - VPIN 2 ³ 150mV, ISOURCE = 100mA				3.6	4.2		3.6		4.2			V
	LOW Output Voltage						VPIN 2 - VPIN 1 ³ 150mV, ISINK = 100mA					0.2	0.4			0.2		0.4	V
	Common Mode Rejection						RS £ 2kW				70	94		70		94			dB
	Supply Voltage Rejection						+VIN = 12 to 18V				66	80		66		80			dB
PWM Comparator (Note 6)
	Minimum Duty Cycle						VCOMPENSATION = +0.4V						0					0	%
	Maximum Duty Cycle						VCOMPENSATION = +3.6V				45	49		45		49			%
Digital Ports				(SYNC,		SHUTDOWN,		and	RESET)
	HIGH Output Voltage						ISOURCE = 40mA				2.4	4.0		2.4		4.0			V
	LOW Output Voltage						ISINK = 3.6mA					0.2	0.4			0.2		0.4	V
	HIGH Input Current						VIH = +2.4V					-125	-200			-125		-200	mA
	LOW Input Current						VIL = +0.4V					-225	-360			-225		-360	mA
	Shutdown Delay						From Pin 8, TJ = 25°C					160				160			ns
Current Limit Comparator (Note 8)
	Sense Voltage						RS £ 50W				90	100	110	80		100		120	mV
	Input Bias Current											-3	-10			-3		-10	mA
	Shutdown Delay						From pin 7, 100mV Overdrive, TJ = 25°C					260				260			ns

Note 4: IL = 0mA.

Note 5: Guaranteed by design, not 100% tested in production. Note 6: FOSC = 40kHz, (RT = 4.12kW ± 1%, CT = 0.01mF± 1%,

RD = 0 W).

Note 7: VCM = 0 to +5.2V Note 8: VCM = 0 to +12V. Note 9: VC = +15V.

Note 10:VIN = +35V, RT = 4.12kW.

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