TL494C, TL494I, TL494M, TL494Y
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074A – JANUARY 1983 – REVISED AUGUST 1995
Copyright 1995, Texas Instruments Incorporated
4–1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
•Complete PWM Power Control Circuitry
•Uncommitted Outputs for 200-mA Sink or
Source Current
•Output Control Selects Single-Ended or
Push-Pull Operation
•Internal Circuitry Prohibits Double Pulse at
Either Output
•Variable Dead T ime Provides Control Over
Total Range
•Internal Regulator Provides a Stable 5-V
Reference Supply With 5% Tolerance
•Circuit Architecture Allows Easy
Synchronization
description
The TL494 incorporates on a single monolithic
chip all the functions required in the construction
of a pulse-width-modulation control circuit.
Designed primarily for power supply control, this
device offers the systems engineer 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 may be bypassed by terminating
RT to the reference output and providing a
sawtooth input to CT, or it may drive the common
circuits in synchronous multiple-rail power
supplies.
AVAILABLE OPTIONS
PACKAGED DEVICES
CHIP
TASURFACE MOUNT
(D)†CHIP CARRIER
(FK) CERAMIC DIP
(J) PLASTIC DIP
(N)
SHRINK
SMALL OUTLINE
(PW)‡
CHIP
FORM
(Y)
0°C to 70°C TL494CD — — TL494CN TL494CPW TL494Y
–40°C to 85°C TL494ID — — TL494IN — —
–55°C to 125°C — TL494MFK TL494MJ — — —
†The D package is available taped and reeled. Add R suffix to device type (e.g., TL494CDR).
‡The PW package is only available left-end taped and reeled.
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
1IN+
1IN–
FEEDBACK
DTC
CT
RT
GND
C1
2IN+
2IN–
REF
OUTPUT CTRL
VCC
C2
E2
E1
TL494C, TL494I ... D, N, OR PW PACKAGE
TL494M ... J PACKAGE
(TOP VIEW)
3212019
910111213
4
5
6
7
8
18
17
16
15
14
REF
OUTPUT CTRL
NC
VCC
C2
FEEDBACK
DTC
NC
CT
RT
TL494M ... FK PACKAGE
(TOP VIEW)
1IN+
1IN–
NC
E1
E2 2IN+
2IN–
GND
C1
NC
VI = GND
VI = Vref Single-ended or parallel output
Normal push-pull operation
INPUT TO
OUTPUT
CTRL OUTPUT FUNCTION
FUNCTION TABLE
NC – No internal connection
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.
On products compliant to MIL-STD-883, Class B, all parameters are
tested unless otherwise noted. On all other products, production
processing does not necessarily include testing of all parameters.
TL494C, TL494I, TL494M, TL494Y
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074A – JANUARY 1983 – REVISED AUGUST 1995
4–2 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
description (continued)
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 may 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. The TL494M is characterized for operation from –55°C to 125°C.
functional block diagram
GND
VCC
Regulator
Reference
C1
Flip-Flop
Pulse-Steering
C1
1D
DTC
CT
RT
Comparator
PWM
+
–
Error Amplifier 1
≈0.1 V Dead-Time Control
Comparator
Oscillator
OUTPUT CTRL
(see Function Table)
0.7 mA
E1
C2
E2
+
–
Error Amplifier 2
1IN+
1IN–
2IN+
2IN–
FEEDBACK
REF
6
5
4
1
2
16
15
3
13
8
9
11
10
12
14
7
Q1
Q2
NOTE A. The terminal numbers indicated apply only to the D, J, N, and PW packages.
TL494C, TL494I, TL494M, TL494Y
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074A – JANUARY 1983 – REVISED AUGUST 1995
4–3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TL494Y chip information
This chip, when properly assembled, display characteristics similar to the TL494C. Thermal compression or
ultrasonic bonding may be used on the doped aluminum bonding pads. The chips may be mounted with
conductive epoxy or a gold-silicon preform.
BONDING PAD ASSIGNMENTS
CHIP THICKNESS: 15 MILS TYPICAL
BONDING PADS: 4 × 4 MILS MINIMUM
TJmax = 150°C
TOLERANCES ARE ±10%.
ALL DIMENSIONS ARE IN MILS.
TL494Y
(2)
(14)
(1)
(3)
(4)
(5)
(6)
(7)
(8)
(15)
(13)
(12)
(11)
(10)
(9)
2IN–
REF
OUTPUT CTRL
VCC
C2
E2
E1C1
RT
CT
DTC
FEEDBACK
1IN–
1IN+
GND
(1)
(2)
(3) (4) (5) (6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
80
94
(16) 2IN+
TL494C, TL494I, TL494M, TL494Y
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074A – JANUARY 1983 – REVISED AUGUST 1995
4–4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)†
TL494C TL494I TL494M UNIT
Supply voltage, VCC (see Note 1) 41 41 41 V
Amplifier input voltage, VIVCC + 0.3 VCC + 0.3 VCC + 0.3 V
Collector output voltage, VO41 41 41 V
Collector output current, IO250 250 250 mA
Continuous total power dissipation See Dissipation Rating Table
Operating free-air temperature range, TA0 to 70 –40 to 85 –55 to 125 °C
Storage temperature range, Tstg –65 to 150 –65 to 150 –65 to 150 °C
Case temperature for 60 seconds, TC: FK package — — 260 °C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds: D, N, or PW
package 260 260 — °C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds: J package — — 300 °C
†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 af fect device reliability.
NOTE 1: All voltage values, except differential voltages, are with respect to the network ground terminal.
DISSIPATION RATING TABLE
PACKAGE TA ≤ 25°C
POWER RATING DERATING
FACTOR DERATE
ABOVE TATA = 70°C
POWER RATING TA = 85°C
POWER RATING TA = 125°C
POWER RATING
D900 mW 7.6 mW/°C 25°C 558 mW 444 mW —
FK 1375 mW 11.0 mW/°C25°C 880 mW 715 mW 275 mW
J 1375 mW 11.0 mW/°C25°C 880 mW 715 mW 275 mW
N 1000 mW 9.2 mW/°C41°C 733 mW 595 mW —
PW 700 mW 5.6 mW/°C 25°C 448 mW — —
recommended operating conditions
TL494C TL494I TL494M
UNIT
MIN MAX MIN MAX MIN MAX
UNIT
Supply voltage, VCC 740 7 40 7 40 V
Amplifier input voltage, VI–0.3 VCC–2 –0.3 VCC–2 –0.3 VCC–2 V
Collector output voltage, VO40 40 40 V
Collector output current (each transistor) 200 200 200 mA
Current into feedback terminal 0.3 0.3 0.3 mA
Oscillator frequency, fosc 1300 1 300 1 300 kHz
T iming capacitor, CT0.47 10000 0.47 10000 0.47 10000 nF
T iming resistor, RT1.8 500 1.8 500 1.8 500 kΩ
Operating free-air temperature, TA0 70 –40 85 –55 125 °C
s
+
ȍ
N
n
+
1(xn
*
X)2
N
*
1
Ǹ
TL494C, TL494I, TL494M, TL494Y
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074A – JANUARY 1983 – REVISED AUGUST 1995
4–5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating free-air temperature range, VCC = 15 V,
f = 10 kHz (unless otherwise noted)
reference section
PARAMETER
TEST CONDITIONS†
TL494C, TL494I TL494M
UNIT
PARAMETER
TEST
CONDITIONS†
MIN TYP‡MAX MIN TYP‡MAX
UNIT
Output voltage (REF) IO = 1 mA 4.75 5 5.25 4.75 5 5.25 V
Input regulation VCC = 7 V to 40 V 2 25 2 25 mV
Output regulation IO = 1 mA to 10 mA 1 15 1 15 mV
Output voltage change with temperature ∆TA = MIN to MAX 2 10 2 30* mV/V
Short-circuit output current§REF = 0 V 25 –25 mA
*On products compliant to MIL-STD-883, Class B, this parameter is not production tested.
†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.
oscillator section, CT = 0.01 µF, RT = 12 kΩ (see Figure 1)
PARAMETER
TEST CONDITIONS†
TL494C, TL494I TL494M
UNIT
PARAMETER
TEST
CONDITIONS†
MIN TYP‡MAX MIN TYP‡MAX
UNIT
Frequency 10 10 kHz
Standard deviation of frequency¶All values of VCC, CT, RT, and TA con-
stant 100 100 Hz/kHz
Frequency change with voltage VCC = 7 V to 40 V, TA = 25°C 1 1 Hz/kHz
Frequency change with temperature#∆TA = MIN to MAX 10 10* Hz/kHz
*On products compliant to MIL-STD-883, Class B, this parameter is not production tested.
†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:
#Temperature coefficient of timing capacitor and timing resistor not taken into account.
error amplifier section (see Figure 2)
PARAMETER TEST CONDITIONS TL494C, TL494I
TL494M UNIT
PARAMETER
TEST
CONDITIONS
MIN TYP‡MAX
UNIT
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 –0.3 to
VCC–2 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 kΩ800 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.
s
+
ȍ
N
n
+
1(xn
*
X)2
N
*
1
Ǹ
TL494C, TL494I, TL494M, TL494Y
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074A – JANUARY 1983 – REVISED AUGUST 1995
4–6 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating free-air temperature range, VCC = 15 V,
f = 10 kHz, TA = 25°C (unless otherwise noted)
reference section
PARAMETER
TEST CONDITIONS
TL494Y
UNIT
PARAMETER
TEST
CONDITIONS
MIN TYP†MAX
UNIT
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‡REF = 0 V 25 mA
oscillator section, CT = 0.01 µF, RT = 12 kΩ (see Figure 1)
PARAMETER
TEST CONDITIONS
TL494Y
UNIT
PARAMETER
TEST
CONDITIONS
MIN TYP†MAX
UNIT
Frequency 10 kHz
Standard deviation of frequency§All values of VCC, CT, R T, and TA constant 100 Hz/kHz
Frequency change with voltage VCC = 7 V to 40 V, TA = 25°C 1 Hz/kHz
error amplifier section (see Figure 2)
PARAMETER
TEST CONDITIONS
TL494Y
UNIT
PARAMETER
TEST
CONDITIONS
MIN TYP†MAX
UNIT
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 kΩ800 kHz
Common-mode rejection ratio ∆VO = 40 V, TA = 25°C 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.
‡Duration of the short circuit should not exceed one second.
§Standard deviation is a measure of the statistical distribution about the mean as derived from the formula:
TL494C, TL494I, TL494M, TL494Y
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074A – JANUARY 1983 – REVISED AUGUST 1995
4–7
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating free-air temperature range, VCC = 15 V,
f = 10 kHz (unless otherwise noted)
output section
PARAMETER TEST CONDITIONS TL494C, TL494I
TL494M, TL494Y UNIT
PARAMETER
TEST
CONDITIONS
MIN TYP†MAX
UNIT
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
Collector emitter saturation voltage
Common emitter VE = 0, IC = 200 mA 1.1 1.3
V
Collector
-
emitter
sat
u
ration
v
oltage
Emitter follower VO(C1 or C2) = 15 V, IE = –200 mA 1.5 2.5
V
Output control input current VI = Vref 3.5 mA
†All typical values except for temperature coefficient are at TA = 25°C.
dead-time control section (see Figure 1)
PARAMETER TEST CONDITIONS TL494C, TL494I
TL494Y TL494M UNIT
PARAMETER
TEST
CONDITIONS
MIN TYP†MAX MIN TYP†MAX
UNIT
Input bias current (DEAD-TIME CTRL) VI = 0 to 5.25 V –2 –10 –2 –10 µA
Maximum duty cycle, each output VI (DEAD-TIME CTRL) = 0,
CT = 0.1 µF, RT = 12 kΩ45% 45% 50%*
Input threshold voltage (DEAD TIME CTRL)
Zero duty cycle 3 3.3 3 3.3
V
I
npu
t
th
res
h
o
ld
vo
lt
age
(DEAD
-
TIME
CTRL)
Maximum duty cycle 0 0*
V
*On products compliant to MIL-STD-883, Class B, this parameter is not production tested.
†All typical values except for temperature coefficient are at TA = 25°C.
PWM comparator section (see Figure 1)
PARAMETER TEST CONDITIONS TL494C, TL494I
TL494M, TL494Y UNIT
MIN TYP†MAX
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
PARAMETER TEST CONDITIONS TL494C, TL494I
TL494Y TL494M UNIT
PARAMETER
TEST
CONDITIONS
MIN TYP†MAX MIN TYP†MAX
UNIT
Standby su
pp
ly current
RT = V
ref
,VCC = 15 V 6 10 6 21
mA
Standb
y
s
u
ppl
y
c
u
rrent
ref,
All other inputs and outputs open VCC = 40 V 9 15 9 26
mA
Average supply current VI (DEAD-TIME CTRL) = 2 V, See Figure 1 7.5 7.5 mA
†All typical values except for temperature coefficient are at TA = 25°C.
TL494C, TL494I, TL494M, TL494Y
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074A – JANUARY 1983 – REVISED AUGUST 1995
4–8 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating free-air temperature range, VCC = 15 V,
f = 10 kHz (unless otherwise noted) (continued)
switching characteristics, TA = 25°C
PARAMETER TEST CONDITIONS TL494C, TL494I
TL494Y TL494M UNIT
MIN TYP†MAX MIN TYP†MAX
Rise time
Common emitter configuration See Figure 3
100 200 100 200* ns
Fall time
Common
-
emitter
config
u
ration
,
See
Fig
u
re
3
25 100 25 100* ns
Rise time
Emitter-follower configuration See Figure 4
100 200 100 200* ns
Fall time
Emitter
-
follower
configuration
,
See
Figure
4
40 100 40 100* ns
*On products compliant to MIL-STD-883, Class B, this parameter is not production tested.
†All typical values except for temperature coefficient are at TA = 25°C.
TL494C, TL494I, TL494M, TL494Y
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074A – JANUARY 1983 – REVISED AUGUST 1995
4–9
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
PARAMETER MEASUREMENT INFORMATION
Test
Inputs DTC
FEEDBACK
RT
CT
GND
50 kΩ
12 kΩ
0.01 µF
VCC
REF
OUTPUT
CTRL
E2
C2
E1
C1 Output 1
Output 2
150 Ω
2 W 150 Ω
2 W
VCC = 15 V
TEST CIRCUIT
1IN+
1IN–
2IN+
2IN–
VCC
VCC
0 V
0 V
Voltage
at C1
Voltage
at C2
Voltage
at CT
DTC
FEEDBACK
0 V
0.7 V
0% MAX 0%
Threshold Voltage
Threshold Voltage
VOLTAGE WAVEFORMS
Duty Cycle
Error
Amplifiers
7
14
12
8
9
11
10
4
3
6
5
1
2
16
15
13
Figure 1. Operational Test Circuit and Waveforms
TL494C, TL494I, TL494M, TL494Y
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074A – JANUARY 1983 – REVISED AUGUST 1995
4–10 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
PARAMETER MEASUREMENT INFORMATION
+
–
+
–
VI
Vref
FEEDBACK
Amplifier Under Test
Other Amplifier
Figure 2. Amplifier Characteristics
Output
Each Output
Circuit
68 Ω
2 W
15 V
CL = 15 pF
(See Note A)
90%
10%
90%
10%
tftr
TEST CIRCUIT OUTPUT VOLTAGE WAVEFORM
NOTE A. CL includes probe and jig capacitance.
Figure 3. Common-Emitter Configuration
Output
Each Output
Circuit
68 Ω
2 W
15 V
CL = 15 pF
(See Note A)
90%
10%
90%
10%
tf
tr
TEST CIRCUIT
OUTPUT VOLTAGE WAVEFORM
NOTE A. CL includes probe and jig capacitance.
Figure 4. Emitter-Follower Configuration
TL494C, TL494I, TL494M, TL494Y
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074A – JANUARY 1983 – REVISED AUGUST 1995
4–11
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
∆f = 1%
†
40
10
100
1 k 4 k 10 k 40 k 100 k 400 k 1 M
f – Oscillator Frequency and Frequency Variation – Hz
OSCILLATOR FREQUENCY AND
FREQUENCY VARIATION†
vs
TIMING RESISTANCE
400
1 k
4 k
10 k
40 k
100 k
RT – Timing Resistance – Ω
0.1 µF
–2%–1%
0% 0.01 µF
0.001 µF
VCC = 15 V
TA = 25°C
CT = 1 µF
Figure 5
†Frequency variation (∆f) is the change in oscillator frequency that occurs over the full temperature range.
10
0
100
20
1 10 100 1 M
A – Amplifier Voltage Amplification – dB
30
f – Frequency – Hz
AMPLIFIER VOLTAGE AMPLIFICATION
vs
FREQUENCY
1 k
VCC = 15 V
∆VO = 3 V
TA = 25°C
10 k
40
50
60
70
80
90
100 k
Figure 6
4–12 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
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pertaining to warranty, patent infringement, and limitation of liability.
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accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty . Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
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Copyright 1998, Texas Instruments Incorporated
