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

Uncommitted Outputs for 200-mA Sink or
Source Current

D

Output Control Selects Single-Ended or
Push-Pull Operation

D

Internal Circuitry Prohibits Double Pulse at
Either Output

D

Variable Dead Time Provides Control Over
Total Range

D

Internal Regulator Provides a Stable 5-V

D, N, NS, OR PW PACKAGE

FEEDBACK

1IN+
1IN–

DTC

CT
RT

GND

C1

(TOP VIEW)

1
2
3
4
5
6
7
8

2IN+

16

2IN–

15
14

REF

13

OUTPUT CTRL

12

V

CC

11

C2

10

E2

9

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 CTRL

VI = GND Single-ended or parallel output

VI = V

ref

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.

OUTPUT FUNCTION

Normal push-pull operation

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.

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Copyright  1999, Texas Instruments Incorporated

1

TL494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074B – JANUARY 1983 – REVISED JULY 1999

AVAILABLE OPTIONS

PACKAGED DEVICES

T

A

0°C to 70°C TL494CD TL494CN TL494CNS TL494CPW TL494Y
–40°C to 85°C TL494ID TL494IN — — —

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

6

RT

5

CT

≈ 0.1 V

4

DTC

SMALL

OUTLINE

(D)

Oscillator

Dead-Time Control

Comparator

PLASTIC

DIP

(N)

OUTLINE

SMALL

(NS)

1D

SHRINK

SMALL

OUTLINE

(PW)

OUTPUT CTRL

(see Function Table)

C1

13

CHIP

FORM

(Y)

Q1

8

C1

9

E1

1IN+
1IN–

2IN+
2IN–

FEEDBACK

1
2

16
15

3

Error Amplifier 1

+
–

Error Amplifier 2

+
–

PWM

Comparator

0.7 mA

Pulse-Steering

Flip-Flop

Reference
Regulator

Q2

11
10

12

14

C2

E2

V

CC

REF

7

GND

2

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Package thermal impedance, θ

(see Notes 2 and 3)

°C

UNIT

Operating free-air temperature, T

°C

TL494

PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074B – JANUARY 1983 – REVISED JULY 1999

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

TL494 UNIT

Supply voltage, VCC (see Note 1) 41 V
Amplifier input voltage, V
Collector output voltage, V
Collector output current, I

Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds D, N, or PW package 260 °C
Storage temperature range, T

†

Stresses beyond those listed under “absolute maximum ratings” 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 “recommended operating conditions” 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),
ambient temperature is PD = (TJ(max) – TA)/

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

I

O

O

D package 73

p

stg

JA

θ

, and TA. The maximum allowable power dissipation at any allowable

θ

JA

JA

. Operating at the absolute maximum TJ of 150°C can impact reliability.

N package 88
NS package 64
PW package 108

VCC+0.3 V

41 V

250 mA

°

–65 to 150 °C

recommended operating conditions

TL494

MIN MAX

Supply voltage, V
Amplifier input voltage, V
Collector output voltage, V
Collector output current (each transistor) 200 mA
Current into feedback terminal 0.3 mA
Oscillator frequency, f
Timing capacitor , C
Timing resistor , R

p

CC

T

I

O

osc

T

p

A

TL494C 0 70
TL494I –40 85

7 40 V

–0.3 VCC–2 V

40 V

1 300 kHz

0.47 10000 nF

1.8 500 kΩ

°

†

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3

TL494

PARAMETER

TEST CONDITIONS

†

UNIT

PARAMETER

TEST CONDITIONS

†

UNIT

PARAMETER

TEST CONDITIONS

UNIT

PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074B – JANUARY 1983 – REVISED JULY 1999

electrical characteristics over recommended operating free-air temperature range, VCC = 15 V,
f = 10 kHz (unless otherwise noted)

reference section

TL494C, TL494I

TYP

TYP

‡

MAX

‡

MAX

MIN

Output voltage (REF) IO = 1 mA 4.75 5 5.25 V
Input regulation VCC = 7 V to 40 V 2 25 mV
Output regulation IO = 1 mA to 10 mA 1 15 mV
Output voltage change with temperature ∆TA = MIN to MAX 2 10 mV/V
Short-circuit output current

†

For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.

‡

All typical values, except for parameter changes with temperature, are at TA = 25°C.

§

Duration of the short circuit should not exceed one second.

§

REF = 0 V 25 mA

oscillator section, CT = 0.01 µF, RT = 12 kΩ (see Figure 1)

TL494, TL494I

MIN

Frequency 10 kHz
Standard deviation of frequency
Frequency change with voltage VCC = 7 V to 40 V, TA = 25°C 1 Hz/kHz
Frequency change with temperature

†

For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.

‡

All typical values, except for parameter changes with temperature, are at TA = 25°C.

¶

Standard deviation is a measure of the statistical distribution about the mean as derived from the formula:

N

ȍ

Ǹ

s

+

(xn*

n+1

N*1

¶

#

2

X)

All values of VCC, CT, RT, and TA constant 100 Hz/kHz

∆TA = MIN to MAX 10 Hz/kHz

#

Temperature coefficient of timing capacitor and timing resistor are not taken into account.

error-amplifier section (see Figure 2)

TL494, TL494I

TYP

‡

MAX

MIN

Input offset voltage VO (FEEDBACK) = 2.5 V 2 10 mV
Input offset current VO (FEEDBACK) = 2.5 V 25 250 nA
Input bias current VO (FEEDBACK) = 2.5 V 0.2 1 µA

Common-mode input voltage range VCC = 7 V to 40 V
Open-loop voltage amplification ∆VO = 3 V, RL = 2 kΩ, VO = 0.5 V to 3.5 V 70 95 dB

Unity-gain bandwidth VO = 0.5 V to 3.5 V, RL = 2 kΩ 800 kHz
Common-mode rejection ratio ∆VO = 40 V, TA = 25°C 65 80 dB
Output sink current (FEEDBACK) VID = –15 mV to –5 V, V (FEEDBACK) = 0.7 V 0.3 0.7 mA
Output source current (FEEDBACK) VID = 15 mV to 5 V, V (FEEDBACK) = 3.5 V –2 mA

‡

All typical values, except for parameter changes with temperature, are at TA = 25°C.

–0.3 to

VCC–2

V

4

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PARAMETER

TEST CONDITIONS

†

UNIT

PARAMETER

TEST CONDITIONS

†

UNIT

PARAMETER

TEST CONDITIONS

UNIT

TL494

PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074B – JANUARY 1983 – REVISED JULY 1999

electrical characteristics over recommended operating free-air temperature range, VCC = 15 V,
f = 10 kHz, T

reference section

Output voltage (REF) IO = 1 mA 5 V
Input regulation VCC = 7 V to 40 V 2 mV
Output regulation IO = 1 mA to 10 mA 1 mV
Short-circuit output current

†

All typical values, except for parameter changes with temperature, are at TA = 25°C.

‡

Duration of the short circuit should not exceed one second.

oscillator section, CT = 0.01 µF, RT = 12 kΩ (see Figure 1)

Frequency 10 kHz
Standard deviation of frequency
Frequency change with voltage VCC = 7 V to 40 V 1 Hz/kHz

†

All typical values, except for parameter changes with temperature, are at TA = 25°C.

§

Standard deviation is a measure of the statistical distribution about the mean as derived from the formula:

s

+

= 25°C (unless otherwise noted)

A

‡

§

Ǹ

N

ȍ

n+1

(xn*

N*1

2

X)

TL494Y

TYP

TL494Y

TYP

†

MAX

†

MAX

MIN

REF = 0 V 25 mA

MIN

All values of VCC, CT, RT, and TA constant 100 Hz/kHz

error-amplifier section (see Figure 2)

TL494Y

TYP

†

MAX

MIN

Input offset voltage VO (FEEDBACK) = 2.5 V 2 mV
Input offset current VO (FEEDBACK) = 2.5 V 25 nA
Input bias current VO (FEEDBACK) = 2.5 V 0.2 µA
Open-loop voltage amplification ∆VO = 3 V, RL = 2 kΩ, VO = 0.5 V to 3.5 V 95 dB
Unity-gain bandwidth VO = 0.5 V to 3.5 V, RL = 2 kΩ 800 kHz
Common-mode rejection ratio ∆VO = 40 V 80 dB
Output sink current (FEEDBACK) VID = –15 mV to –5 V, V (FEEDBACK) = 0.7 V 0.7 mA

†

All typical values, except for parameter changes with temperature, are at TA = 25°C.

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5

TL494

PARAMETER

TEST CONDITIONS

UNIT

Collector-emitter saturation voltage

V

PARAMETER

TEST CONDITIONS

UNIT

Input threshold voltage (DEAD-TIME CTRL)

V

PARAMETER

TEST CONDITIONS

UNIT

PARAMETER

TEST CONDITIONS

UNIT

Standby supply current

RT

V

All other inputs and outputs open

mA

PARAMETER

TEST CONDITIONS

UNIT

Common-emitter configuration

See Figure 3

Emitter-follower configuration

See Figure 4

PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074B – JANUARY 1983 – REVISED JULY 1999

electrical characteristics over recommended operating free-air temperature range, VCC = 15 V,
f = 10 kHz (unless otherwise noted)

output section

TL494, TL494Y

TYP

TYP

†

†

MAX

3.5 mA

MAX

MIN

Collector off-state current VCE = 40 V, VCC = 40 V 2 100 µA
Emitter off-state current VCC = VC = 40 V, VE = 0 –100 µA

Common emitter VE = 0, IC = 200 mA 1.1 1.3
Emitter follower V

Output control input current VI = V

†

All typical values except for temperature coefficient are at TA = 25°C.

O(C1 or C2)

= 15 V, IE = –200 mA 1.5 2.5

ref

dead-time control section (see Figure 1)

TL494, TL494Y

MIN

Input bias current (DEAD-TIME CTRL) VI = 0 to 5.25 V –2 –10 µA
Maximum duty cycle, each output VI (DEAD-TIME CTRL) = 0, CT = 0.1 µF, RT = 12 kΩ 45%

p

†

All typical values except for temperature coefficient are at TA = 25°C.

Zero duty cycle 3 3.3
Maximum duty cycle 0

PWM comparator section (see Figure 1)

TL494, TL494Y

TYP

†

MAX

MIN

Input threshold voltage (FEEDBACK) Zero duty cycle 4 4.5 V
Input sink current (FEEDBACK) V (FEEDBACK) = 0.7 V 0.3 0.7 mA

†

All typical values except for temperature coefficient are at TA = 25°C.

total device

TL494, TL494Y

TYP

†

MAX

MIN

pp

Average supply current VI (DEAD-TIME CTRL) = 2 V, See Figure 1 7.5 mA

†

All typical values except for temperature coefficient are at TA = 25°C.

=

ref

,

p

p

VCC = 15 V 6 10

p

VCC = 40 V 9 15

switching characteristics, TA = 25°C

TL494, TL494Y

†

TYP

MAX

100 200 ns

25 100 ns

100 200 ns

40 100 ns

Rise time
Fall time
Rise time
Fall time

†

All typical values except for temperature coefficient are at TA = 25°C.

MIN

,

,

6

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TL494

PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074B – JANUARY 1983 – REVISED JULY 1999

PARAMETER MEASUREMENT INFORMATION

VCC = 15 V

Voltage

at C1

Voltage

at C2

Test

Inputs

50 kΩ

12 kΩ

0.01 µF

4

DTC

3

FEEDBACK

6

RT

5

CT

1

1IN+

2

1IN–

16

2IN+

15

2IN–

13

OUTPUT
CTRL

12

V

CC

Error
Amplifiers

GND

7

TEST CIRCUIT

C1

C2

REF

E1

E2

8
9

11

10

14

150 Ω
2 W

150 Ω
2 W

Output 1

Output 2

V

0 V
V

0 V

CC

CC

Voltage

at CT

DTC

0 V

FEEDBACK

0.7 V

Duty Cycle

Threshold Voltage

Figure 1. Operational Test Circuit and Waveforms

Threshold Voltage

0%

VOLTAGE WAVEFORMS

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MAX

0%

7

TL494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074B – JANUARY 1983 – REVISED JULY 1999

PARAMETER MEASUREMENT INFORMATION

Amplifier Under Test

+

V

I

–

+

FEEDBACK

15 V

Each Output
Circuit

TEST CIRCUIT OUTPUT VOLT AGE WAVEFORM

NOTE A: CL includes probe and jig capacitance.

Figure 3. Common-Emitter Configuration

15 V

Each Output
Circuit

V

ref

–

Other Amplifier

Figure 2. Amplifier Characteristics

68 Ω
2 W

Output

CL = 15 pF
(See Note A)

90%

10%

t

f

10%

90%

t

r

CL = 15 pF

(See Note A)

TEST CIRCUIT OUTPUT VOLTAGE WAVEFORM

NOTE A: CL includes probe and jig capacitance.

Figure 4. Emitter-Follower Configuration

8

Output

68 Ω
2 W

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90%

10%

90%

10%

t

r

t

f

TL494

PULSE-WIDTH-MODULATION CONTROL CIRCUITS

SLVS074B – JANUARY 1983 – REVISED JULY 1999

TYPICAL CHARACTERISTICS

OSCILLATOR FREQUENCY AND

FREQUENCY VARIATION

†

vs

TIMING RESISTANCE

100 k

40 k

–2%

10 k

4 k

1 k

400

100

40

10

f – Oscillator Frequency and Frequency Variation – Hz

1 k 4 k 10 k 40 k 100 k 400 k 1 M

†

Frequency variation (∆f) is the change in oscillator frequency that occurs over the full temperature range.

–1%

0%

0.1 µF

CT = 1 µF

RT – Timing Resistance – Ω

0.01 µF

Df = 1%

VCC = 15 V
TA = 25°C

0.001 µF

†

Figure 5

AMPLIFIER VOLTAGE AMPLIFICATION

vs

FREQUENCY

100

90

80

70
60

50

40

30

20

A – Amplifier Voltage Amplification – dB

10

0

1 10 100 1 M

f – Frequency – Hz

1 k

VCC = 15 V
∆VO = 3 V
TA = 25°C

10 k

Figure 6

100 k

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9

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Copyright  1999, Texas Instruments Incorporated