UNITRODE UC1526, UC2526, UC3526 Technical data

UC1526

UC2526

UC3526

Regulating Pulse Width Modulator

FEATURES

∙8 To 35V Operation

∙5V Reference Trimmed To ±1%

∙1Hz To 400kHz Oscillator Range

∙Dual 100mA Source/Sink Outputs

∙Digital Current Limiting

∙Double Pulse Suppression

∙Programmable Deadtime

∙Under-Voltage Lockout

∙Single Pulse Metering

∙Programmable Soft-Start

∙Wide Current Limit Common Mode Range

∙TTL/CMOS Compatible Logic Ports

∙Symmetry Correction Capability

∙Guaranteed 6 Unit Synchronization

DESCRIPTION

The UC1526 is a high performance monolithic pulse width modulator circuit designed for fixed-frequency switching regulators and other power control applications. Included in an 18-pin dual-in-line package are a temperature compensated voltage reference, sawtooth oscillator, error amplifier, pulse width modulator, pulse metering and setting logic, and two low impedance power drivers. Also included are protective features such as soft-start and under-voltage lockout, digital current limiting, double pulse inhibit, a data latch for single pulse metering, adjustable deadtime, and provision for symmetry correction inputs. For ease of interface, all digital control ports are TTL and B-series CMOS compatible. Active LOW logic design allows wired-OR connections for maximum flexibility. This versatile device can be used to implement single-ended or push-pull switching regulators of either polarity, both transformerless and transformer coupled. The UC1526 is characterized for operation over the full military temperature range of -55°C to +125°C. The UC2526 is characterized for operation from -25°C to +85°C, and the UC3526 is characterized for operation from 0° to +70°C.

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.

UC1526

UC2526

UC3526

RECOMMENDED OPERATING CONDITIONS (Note 3)

Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +8V 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 400kHz Oscillator Timing Resistor . . . . . . . . . . . . . . . . . . . 2kΩ to 150kΩ Oscillator Timing Capacitor . . . . . . . . . . . . . . . . . . . 1nF to 20μF Available Deadtime Range at 40kHz . . . . . . . . . . . . . 3% to 50% Operating Ambient Temperature Range

UC1526 . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55°C to +125°C UC2526 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -25°C to +85°C UC3526 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -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)	PLCC-20, LCC-20	PACKAGE PIN FUNCTION
J or N Package, DW Package	(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

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

PARAMETER	TEST CONDITIONS	UC1526 / UC2526				UC3526		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 = 8 to 35V		10	20		10	30	mV
Load Regulation	IL = 0 to 20mA		10	30		10	50	mV
Temperature Stability	Over Operating TJ		15	50		15	50	mV
Total Output	Over Recommended	4.90	5.00	5.10	4.85	5.00	5.15	V
Voltage Range	Operating 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 = 4.8V	2.4	4.8		2.4	4.8		V

Note 4: IL = 0mA.

UC1526

UC2526

UC3526

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

PARAMETER					TEST CONDITIONS	UC1526 / UC2526				UC3526		UNITS
						MIN	TYP	MAX	MIN	TYP	MAX
Oscillator Section (Note 5)
Initial Accuracy			TJ = + 25°C				±3	±8		±3	±8	%
Voltage Stability			+VIN = 8 to 35V				0.5	1		0.5	1	%
Temperature Stability			Over Operating TJ				7	10		3	5	%
Minimum Frequency			RT = 150kW, CT = 20mF					1			1	Hz
Maximum Frequency			RT = 2kW, CT = 1.0nF			400			400			kHz
Sawtooth Peak Voltage			+VIN = 35V				3.0	3.5		3.0	3.5	V
Sawtooth Valley Voltage			+VIN = 8V			0.5	1.0		0.5	1.0		V
Error Amplifier Section (Note 6)
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			VPIN1-VPIN2 ³ 150mV, ISOURCE =			3.6	4.2		3.6	4.2		V
			100mA
LOW Output Voltage			VPIN2-VPIN1 ³ 150mV, ISINK = 100mA				0.2	0.4		0.2	0.4	V
Common Mode Rejection			Rs £ 12kW			70	94		70	94		dB
Supply Voltage Rejection			+VIN = 12 to 18V			66	80		66	80		dB
PWM Comparator (Note 5)
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
Current LImit Comparator (Note 7)
Sense Voltage			RS £ 50W			90	100	110	80	100	120	mV
Input Bias Current							-3	-10		-3	-10	mA
Soft-Start Section
Error Clamp Voltage					= +0.4V		0.1	0.4		0.1	0.4	V
Error Clamp Voltage			RESET		= +0.4V		0.1	0.4		0.1	0.4	V
Cs Charging Current						50	100	150	50	100	150	mA
Cs Charging Current			RESET		=+2.4V	50	100	150	50	100	150	mA
Output Drivers (Each Output) (Note 8)
HIGH Output Voltage			ISOURCE = 20mA			12.5	13.5		12.5	13.5		V
			ISOURCE = 100mA			12	13		12	13		V
LOW Output Voltage			ISINK = 20mA				0.2	0.3		0.2	0.3	V
			ISINK = 100mA				1.2	2.0		1.2	2.0	V
Collector Leakage			VC = 40V				50	150		50	150	mA
Rise Time			CL = 1000pF				0.3	0.6		0.3	0.6	ms
Fall Time			CL = 1000pF				0.1	0.2		0.1	0.2	ms
Power Consumption (Note 9)			____________
Standby Current			SHUTDOWN = +0.4V				18	30		18	30	mA

Note 4: IL = 0mA.

Note 5: FOSC = 40kHz (RT = 4.12kW ± 1%, CT = 0.1mF ± 1%, RD = 0W)

Note 6: VCM = 0 to +5.2V Note 8: VC = +15V

Note 9: +VIN = +35V, RT = 4.12kW

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