Texas Instruments TL494CN, TL494CJ, TL494CDR, TL494CD, TL494MJB Datasheet

						TL494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
	SLVS074B ± JANUARY 1983 ± REVISED JULY 1999
D Complete PWM Power Control Circuitry	D, N, NS, OR PW PACKAGE
D Uncommitted Outputs for 200-mA Sink or			(TOP VIEW)
Source Current	1IN+		1	16		2IN+
D Output Control Selects Single-Ended or
	1IN±		2	15		2IN±
Push-Pull Operation	FEEDBACK		3	14		REF
D Internal Circuitry Prohibits Double Pulse at	DTC		4	13		OUTPUT CTRL
Either Output	CT		5	12		VCC
			6	11
D Variable Dead Time Provides Control Over	RT					C2
			7	10
Total Range	GND					E2
			8	9
D Internal Regulator Provides a Stable 5-V	C1					E1

Reference Supply With 5% Tolerance

D Circuit Architecture Allows Easy

Synchronization

description

The TL494 incorporates all the functions required in the construction of a pulse-width-modulation (PWM) control circuit on a single chip. Designed primarily for power-supply control, this device offers the flexibility to tailor the power-supply control circuitry to a specific application.

The TL494 contains two error amplifiers, an on-chip adjustable oscillator, a dead-time control (DTC) comparator, a pulse-steering control flip-flop, a 5-V, 5%-precision regulator, and output-control circuits.

The error amplifiers exhibit a common-mode voltage range from ±0.3 V to VCC ± 2 V. The dead-time control comparator has a fixed offset that provides approximately 5% dead time. The on-chip oscillator can be bypassed by terminating RT to the reference output and providing a sawtooth input to CT, or it can drive the common circuits in synchronous multiple-rail power supplies.

The uncommitted output transistors provide either common-emitter or emitter-follower output capability. The TL494 provides for push-pull or single-ended output operation, which can be selected through the output-control function. The architecture of this device prohibits the possibility of either output being pulsed twice during push-pull operation.

The TL494C is characterized for operation from 0°C to 70°C. The TL494I is characterized for operation from ±40°C to 85°C.

		FUNCTION TABLE
	INPUT TO		OUTPUT FUNCTION
	OUTPUT CTRL
	VI = GND		Single-ended or parallel output
	VI = Vref		Normal push-pull operation

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters.

Copyright 1999, Texas Instruments Incorporated

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TL494

PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074B ± JANUARY 1983 ± REVISED JULY 1999

AVAILABLE OPTIONS

			PACKAGED DEVICES
						CHIP
		SMALL	PLASTIC	SMALL	SHRINK
	TA				SMALL	FORM
		OUTLINE	DIP	OUTLINE
					OUTLINE	(Y)
		(D)	(N)	(NS)
					(PW)
	0°C to 70°C	TL494CD	TL494CN	TL494CNS	TL494CPW	TL494Y
	±40°C to 85°C	TL494ID	TL494IN	Ð	Ð	Ð

The D, NS, and PW packages are available taped and reeled. Add the suffix R to device type (e.g.,

TL494CDR). Chip forms are tested at 25°C.

functional block diagram
				OUTPUT CTRL
				(see Function Table)
RT	6			13
		Oscillator
CT	5			Q1	8
		Dead-Time Control		1D		C1
					9
	≈ 0.1 V	Comparator				E1
DTC	4			C1
	Error Amplifier 1		PWM	Q2	11	C2
			Comparator
1IN+	1				10
		+				E2
	2			Pulse-Steering
1IN±		±
				Flip-Flop

		Error Amplifier 2		12	V
2IN+	16	+			CC
2IN±	15	±	Reference	14	REF
			Regulator
				7	GND
FEEDBACK	3		0.7 mA

2	POST OFFICE BOX 655303 •DALLAS, TEXAS 75265

TL494

PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074B ± JANUARY 1983 ± REVISED JULY 1999

absolute maximum ratings over operating free-air temperature range (unless otherwise noted)²

			TL494	UNIT
	Supply voltage, VCC (see Note 1)		41	V
	Amplifier input voltage, VI		VCC+0.3	V
	Collector output voltage, VO		41	V
	Collector output current, IO		250	mA
		D package	73
	Package thermal impedance, θJA (see Notes 2 and 3)	N package	88	°C
		NS package	64
		PW package	108
	Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds	D, N, or PW package	260	°C
	Storage temperature range, Tstg		±65 to 150	°C

²Stresses beyond those listed under ªabsolute maximum ratingsº may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under ªrecommended operating conditionsº is not

implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

NOTES: 1. All voltage values, except differential voltages, are with respect to the network ground terminal.

2.Maximum power dissipation is a function of TJ(max), θJA, and TA. The maximum allowable power dissipation at any allowable ambient temperature is PD = (TJ(max) ± TA)/θJA. Operating at the absolute maximum TJ of 150°C can impact reliability.

3.The package thermal impedance is calculated in accordance with JESD 51, except for through-hole packages, which use a trace length of zero.

recommended operating conditions

			TL494		UNIT
			MIN	MAX
	Supply voltage, VCC		7	40	V
	Amplifier input voltage, VI		±0.3	VCC±2	V
	Collector output voltage, VO			40	V
	Collector output current (each transistor)			200	mA
	Current into feedback terminal			0.3	mA
	Oscillator frequency, fosc		1	300	kHz
	Timing capacitor, CT		0.47	10000	nF
	Timing resistor, RT		1.8	500	kΩ
	Operating free-air temperature, TA	TL494C	0	70	°C
		TL494I	±40	85

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