www.fairchildsemi.com
TL494
SMPS Controller
Features
• Internal regulator provides a stable 5V reference supply
trimmed to 5%
• Uncommitted output TR for 200mA sink or source
current
• Output control for push-pull or single-ended operation
• Variable duty cycle by dead time control (pin 4) Complete
PWM control circuit
• On-chip oscillator with master or slave operation
• Internal circuit prohibits double pulse at either output
Description
The TL494 is used for the control circuit of the PWM
switching regulator. The TL494 consists of 5V reference
voltage circuit, two error amplifiers, flip flop, an output con-
trol circuit, a PWM comparator, a dead time comparator and
an oscillator. This device can be operated in the switching
frequency of 1 KHz to 300 KHz.
16-DIP
1
16-SOP
1
Internal Block Diagram
Rev. 5.0
©2000 Fairchild Semiconductor International
TL494
Electrical Characteristics
(V
CC
= 20V, f = 10KHz, T
A
= 0°C to + 70°C, unless otherwise specified)
Parameter
REFERENCE SECTION
Reference Output Voltage
Line Regulation
Temperature Coefficient of V
REF
Load Regulation
Short-Circuit Output Currnet
OSCILLATOR SECTION
Oscillation Frequency
Frequency Change with Temperature
DEAD TIME CONTROL SECTION
Input Bias Current
Maximum Duty Cycle
Input Threshold Voltage
ERROR AMP SECTION
Input Offset Voltage
Input Offset Current
Input Bias Current
Common Mode Input Voltage
Open-Loop Voltage Gain
Unit-Gain Bandwidth
PWM COMPARATOR SECTION
Input Threshold Voltage
Input Sink Currnet
OUTPUT SECTION
Output Saturation Voltage
Common Emitter
Common Collector
Collector Off-State Currnet
Emitter Off-State Current
TOTAL DEVICE
Supply Current
Rise Time
Common Emitter
Common Collector
Fall Time
Common Emitter
Common Collector
I
CC
t
R
-
-
t
F
-
-
Pin 6 = V
REF
, V
CC
= 15V
-
-
-
-
-
-
-
-
-
-
-
-
-
6
-
100
100
-
25
40
10
-
200
200
-
100
100
mA
-
ns
-
ns
OUTPUT SWITCHING CHARACTERISTIC
V
CE(SAT)
V
CC(SAT)
I
C(OFF)
I
E(OFF)
V
E
= 0, I
C
= 200mA
V
C
= 15V, I
E
= -200mA
V
CC
= 40V, V
CE
= 40V
V
CC
= V
C
= 40V, V
E
= 0
-
-
-
-
1.1
1.5
2
-
1.3
2.5
100
-100
V
µA
V
ITH
I
SINK
Zero Duty Cycle
V
3
=0.7V
-
-0.3
4
-0.7
4.5
-
V
mV
V
IO
I
IO
I
BIAS
V
CM
G
VO
BW
V
3
= 2.5V
V
3
= 2.5V
V
3
= 2.5V
7V
≤
V
CC
≤
40V
0.5V
≤
V
3
≤3
.5V
-
-
-
-
-0.3
70
-
2.0
25
0.2
-
95
650
10
250
1.0
V
CC
-
-
mV
mA
µA
V
dB
KHz
I
BIAS
D
(MAX)
V
ITH
V
CC
= 15V, 0V≤V
4
≤5.25V
V
CC
= 15V, V
4
= 0V
O.C Pin = V
REF
Zero Duty Cycle
Max. Duty Cycle
-
45
-
0
-2.0
-
3.0
-
-10
-
3.3
-
µA
%
V
f
∆f/∆T
C
T
= 0.01µF, R
T
= 12KΩ
C
T
= 0.01µF, R
T
= 12KΩ
-
-
10
-
-
2
KHz
%
V
REF
∆V
REF
∆V
REF
/∆T
∆V
REF
I
SC
I
REF
= 1mA
V
CC
= 7V to 40V
T
A
= 0°C to 70°C
I
REF
= 1mA to 10mA
V
REF
= 0V
4.75
-
-
-
10
5.0
2.0
0.01
1.0
35
5.25
25
0.03
15
50
V
mV
%/°C
mV
mA
Symbol
Conditions
Min.
Typ.
Max.
Unit
3
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