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FEATURES
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
V
CC
C2
E2
E1
D, DB, N, NS, OR PW PACKAGE
(TOP VIEW)
DESCRIPTION
TL494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074E JANUARY 1983 REVISED FEBRUARY 2005
·
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 Time Provides Control Over
Total Range
·
Internal Regulator Provides a Stable 5-V
Reference Supply With 5% Tolerance
·
Circuit Architecture Allows Easy
Synchronization
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 V
CC
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.
AVAILABLE OPTIONS
PACKAGED DEVICES
(1)
SHRINK SMALL
THIN SHRINK
T
A
SMALL OUTLINE
PLASTIC DIP
SMALL OUTLINE
OUTLINE
SMALL OUTLINE
(D)
(N)
(NS)
(DB)
(PW)
0
°
C to 70
°
C
TL494CD
TL494CN
TL494CNS
TL494CDB
TL494CPW
40
°
C to 85
°
C
TL494ID
TL494IN
--
--
--
(1)
The D, DB, NS, and PW packages are available taped and reeled. Add the suffix R to device type (e.g., TL494CDR).
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.
Copyright © 19832005, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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GND
V
CC
Reference
Regulator
C1
Pulse-Steering
Flip-Flop
C1
1D
DTC
CT
RT
PWM
Comparator
+
-
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
0.7 V
TL494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074E JANUARY 1983 REVISED FEBRUARY 2005
FUNCTION TABLE
INPUT TO
OUTPUT FUNCTION
OUTPUT CTRL
V
I
= GND
Single-ended or parallel output
V
I
= V
ref
Normal push-pull operation
FUNCTIONAL BLOCK DIAGRAM
2
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Absolute Maximum Ratings
(1)
Recommended Operating Conditions
TL494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074E JANUARY 1983 REVISED FEBRUARY 2005
over operating free-air temperature range (unless otherwise noted)
MIN
MAX
UNIT
V
CC
Supply voltage
(2)
41
V
V
I
Amplifier input voltage
V
CC
+ 0.3
V
V
O
Collector output voltage
41
V
I
O
Collector output current
250
mA
D package
73
DB package
82
JA
Package thermal impedance
(3) (4)
N package
67
°
C/W
NS package
64
PW package
108
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds
260
°
C
T
stg
Storage temperature range
65
150
°
C
(1)
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.
(2)
All voltages are with respect to the network ground terminal.
(3)
Maximum power disipation is a function of T
J
(max),
JA
, and T
A
. The maximum allowable power dissipation at any allowable ambient
temperatire is P
D
= (T
J
(max) T
A
)/
JA
. Operating at the absolute maximum T
J
of 150
°
C can affect reliability.
(4)
The package thermal impedance is calculated in accordance with JESD 51-7.
MIN
MAX
UNIT
V
CC
Supply voltage
7
40
V
V
I
Amplifier input voltage
0.3
V
CC
2
V
V
O
Collector output voltage
40
V
Collector output current (each transistor)
200
mA
Current into feedback terminal
0.3
mA
f
OSC
Oscillator frequency
1
300
kHz
C
T
Timing capacitor
0.47
10000
nF
R
T
Timing resistor
1.8
500
k
TL494C
0
70
T
A
Operating free-air temperature
°
C
TL494I
40
85
3
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s
+
N
n
+
1
(x
n
*
X)
2
N
*
1
Electrical Characteristics
Reference Section
Oscillator Section
Error-Amplifier Section
TL494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074E JANUARY 1983 REVISED FEBRUARY 2005
over recommended operating free-air temperature range, V
CC
= 15 V, f = 10 kHz (unless otherwise noted)
TL494C, TL494I
PARAMETER
TEST CONDITIONS
(1)
UNIT
MIN TYP
(2)
MAX
Output voltage (REF)
I
O
= 1 mA
4.75
5
5.25
V
Input regulation
V
CC
= 7 V to 40 V
2
25
mV
Output regulation
I
O
= 1 mA to 10 mA
1
15
mV
Output voltage change with temperature
T
A
= MIN to MAX
2
10
mV/V
Short-circuit output current
(3)
REF = 0 V
25
mA
(1)
For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
(2)
All typical values, except for parameter changes with temperature, are at T
A
= 25
°
C.
(3)
Duration of short circuit should not exceed one second.
C
T
= 0.01
µ
F, R
T
= 12 k
(see Figure 1)
TL494C, TL494I
PARAMETER
TEST CONDITIONS
(1)
UNIT
MIN TYP
(2)
MAX
Frequency
10
kHz
Standard deviation of frequency
(3)
All values of V
CC
, C
T
, R
T
, and T
A
constant
100
Hz/kHz
Frequency change with voltage
V
CC
= 7 V to 40 V, T
A
= 25
°
C
1
Hz/kHz
Frequency change with temperature
(4)
T
A
= MIN to MAX
10
Hz/kHz
(1)
For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
(2)
All typical values, except for parameter changes with temperature, are at T
A
= 25
°
C.
(3)
Standard deviation is a measure of the statistical distribution about the mean as derived from the formula:
(4)
Temperature coefficient of timing capacitor and timing resistor are not taken into account.
See Figure 2
TL494C, TL494I
PARAMETER
TEST CONDITIONS
UNIT
MIN TYP
(1)
MAX
Input offset voltage
V
O
(FEEDBACK) = 2.5 V
2
10
mV
Input offset current
V
O
(FEEDBACK) = 2.5 V
25
250
nA
Input bias current
V
O
(FEEDBACK) = 2.5 V
0.2
1
µ
A
0.3 to
Common-mode input voltage range
V
CC
= 7 V to 40 V
V
V
CC
2
Open-loop voltage amplification
V
O
= 3 V, V
O
= 0.5 V to 3.5 V, R
L
= 2 k
70
95
dB
Unity-gain bandwidth
V
O
= 0.5 V to 3.5 V, R
L
= 2 k
800
kHz
Common-mode rejection ratio
V
O
= 40 V, T
A
= 25
°
C
65
80
dB
Output sink current (FEEDBACK)
V
ID
= 15 mV to 5 V, V (FEEDBACK) = 0.7 V
0.3
0.7
mA
Output source current (FEEDBACK)
V
ID
= 15 mV to 5 V, V (FEEDBACK) = 3.5 V
2
mA
(1)
All typical values, except for parameter changes with temperature, are at T
A
= 25
°
C.
4
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Electrical Characteristics
Output Section
Dead-Time Control Section
PWM Comparator Section
Total Device
Switching Characteristics
TL494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
SLVS074E JANUARY 1983 REVISED FEBRUARY 2005
over recommended operating free-air temperature range, V
CC
= 15 V, f = 10 kHz (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
(1)
MAX
UNIT
Collector off-state current
V
CE
= 40 V, V
CC
= 40 V
2
100
µ
A
Emitter off-state current
V
CC
= V
C
= 40 V, V
E
= 0
100
µ
A
Common emitter
V
E
= 0, I
C
= 200 mA
1.1
1.3
Collector-emitter saturation voltage
V
Emitter follower
V
O(C1 or C2)
= 15 V, I
E
= 200 mA
1.5
2.5
Output control input current
V
I
= V
ref
3.5
mA
(1)
All typical values, except for temperature coefficient, are at T
A
= 25
°
C.
See Figure 1
PARAMETER
TEST CONDITIONS
MIN TYP
(1)
MAX
UNIT
Input bias current (DEAD-TIME CTRL)
V
I
= 0 to 5.25 V
2
10
µ
A
V
I
(DEAD-TIME CTRL) = 0, C
T
= 0.01
µ
F,
Maximum duty cycle, each output
45
%
R
T
= 12 k
Zero duty cycle
3
3.3
Input threshold voltage (DEAD-TIME CTRL)
V
Maximum duty cycle
0
(1)
All typical values, except for temperature coefficient, are at T
A
= 25
°
C.
See Figure 1
PARAMETER
TEST CONDITIONS
MIN TYP
(1)
MAX
UNIT
Input threshold voltage (FEEDBACK)
Zero duty cyle
4
4.5
V
Input sink current (FEEDBACK)
V (FEEDBACK) = 0.7 V
0.3
0.7
mA
(1)
All typical values, except for temperature coefficient, are at T
A
= 25
°
C.
PARAMETER
TEST CONDITIONS
MIN TYP
(1)
MAX
UNIT
V
CC
= 15 V
6
10
R
T
= V
ref
,
Standby supply current
mA
All other inputs and outputs open
V
CC
= 40 V
9
15
Average supply current
V
I
(DEAD-TIME CTRL) = 2 V, See Figure 1
7.5
mA
(1)
All typical values, except for temperature coefficient, are at T
A
= 25
°
C.
T
A
= 25
°
C
PARAMETER
TEST CONDITIONS
MIN TYP
(1)
MAX
UNIT
Rise time
100
200
ns
Common-emitter configuration, See Figure 3
Fall time
25
100
ns
Rise time
100
200
ns
Emitter-follower configuration, See Figure 4
Fall time
40
100
ns
(1)
All typical values, except for temperature coefficient, are at T
A
= 25
°
C.
5
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