©2000 Fairchild Semiconductor International
www.fairchildsemi.com
Rev. 5.0
Features
• Internal regulator provides a stable 5V refer ence supply
trimmed to 5%
• Unc ommitt ed ou tput TR for 200mA s ink or sour c e
current
• Outp ut cont r ol fo r push-pu ll or singl e-ended ope rat ion
• Variable duty cycle by dead time control (pin 4) Complete
PWM control circu it
• 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 reg ul a tor. Th e TL4 94 consist s of 5V re fe r e nce
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
frequenc y of 1 KHz to 300 KHz.
16-DIP
16-SOP
1
1
Internal Block Diagram
TL494
SMPS Controller
TL494
2
Absolute Maximum Ratings
Parameter Symbol Value Unit
Supply Voltage VCC 42 V
Collector Supply Voltage VC42 V
Output Current IO250 mA
Amplifier Input Voltage VIN VCC + 0.3 V
Power Dissipation (TA = 25°C) PD1 (TL494CN)
0.9 (TL494CD) W
Operating Temperature Range TOPR 0 ~ +70 °C
Storage Temperature Range TSTG -65 ~ + 150 °C
TL494
3
Electrical Characteristics
(VCC = 20V, f = 10KHz, TA = 0°C to + 70°C, unless otherwise specified)
Parameter Symbol Conditions Min. Typ. Max. Unit
REFERENCE SECTION
Reference Output Voltage VREF IREF = 1mA 4.75 5.0 5.25 V
Line Regulation ∆VREF VCC = 7V to 40V - 2.0 25 mV
Temperature Coefficient of VREF ∆VREF/∆TT
A = 0°C to 70°C - 0.01 0.03 %/°C
Load Regulation ∆VREF IREF = 1mA to 10mA - 1.0 15 mV
Short-Circuit Output Currnet ISC VREF = 0V 10 35 50 mA
OSCILLATOR SECTION
Oscillation Frequency f CT = 0.01µF, RT = 12KΩ-10-KHz
Frequency Change with Temperature ∆f/∆TC
T = 0.01µF, RT = 12KΩ--2%
DEAD TIME CONTROL SECTION
Input Bias Current IBIAS VCC = 15V, 0V≤V4≤5.25V - -2.0 -10 µA
Maximum Duty Cycle D(MAX) VCC = 15V, V4 = 0V
O.C Pin = VREF 45 - - %
Input Threshold Voltage VITH Zero Duty Cycle - 3.0 3.3 V
Max. Duty Cycle 0 - -
ERROR AMP SECTION
Input Offset Voltage VIO V3 = 2.5V - 2.0 10 mV
Input Offset Current IIO V3 = 2.5V - 25 250 mA
Input Bias Current IBIAS V3 = 2.5V - 0.2 1.0 µA
Common Mode Input Voltage VCM 7V ≤ VCC ≤ 40V -0.3 - VCC V
Open-Loop Voltage Gain GVO 0.5V ≤ V3 ≤3 .5V 70 95 - dB
Unit-Gain Bandwidth BW -- 650 - KHz
PWM COMPARATOR SECTION
Input Threshold Voltage VITH Zero Duty Cycle - 4 4.5 V
Input Sink Currnet ISINK V3=0.7V -0.3 -0.7 - mV
OUTPUT S ECTION
Output Saturation Voltage
Common Emitter VCE(SAT) VE = 0, IC = 200mA - 1.1 1.3 V
Common Collector VCC(SAT) VC = 15V, IE = -200mA - 1.5 2.5
Collector Off-State Currnet IC(OFF) VCC = 40V, VCE = 40V - 2 100 µA
Emitter Off-State Current IE(OFF) VCC = VC = 40V, VE = 0 - - -100
TOTAL DEVICE
Supply Current ICC Pin 6 = VREF, VCC = 15V - 6 10 mA
OUTPUT SWITCHING CHARACTERISTIC
Rise Time tR-----
Common Emitter - -- 100 200 ns
Common Collector - -- 100 200
Fall Time tF-----
Common Emitter - -- 25 100 ns
Common Collector - -- 40 100
TL494
4
Typical Application
Pulse Width Modulated Step-down Converter
TL494
TL494
5
Mechanical Dimensions
Package
#1
#8 #9
#16
6.40
±0.20
7.62
0.300
2.54
0.100
0.252
±0.008
0~15°
0.25
+0.10
–0.05
0.010
+0.004
–0.002
3.30
±0.30
0.130
±0.012
3.25
±0.20
0.128
±0.008
19.40
±0.20
0.764
±0.008
19.80
0.780 MAX
5.08
0.200
0.38
0.014
MAX
MIN
0.81
0.032
()
0.46
±0.10
0.018
±0.004
0.059
±0.004
1.50
±0.10
16-DIP
TL494
6
Mechanical Dimensions (Continued)
Package
0.70
±0.20
0.0275
±0.008
#1
#8 #9
#16
9.90
±0.20
0.39
±0.008
1.27
0.050
5.72
0.225
1.55
±0.10
0.061
±0.004
0.05
0.002
6.00
±0.30
0.236
±0.012
3.95
±0.20
0.156
±0.008
10.30
0.405 MAX
0~8°
0.51
0.020
()
1.80
0.071
MAX0.10
MAX0.004
MAX
MIN
+
0.10
-0.05
0.20+
0.004
-0.002
0.008
+
0.10
-0.05
0.406+
0.004
-0.002
0.016
16-SOP
TL494
7
Ordering Information
Product Number Package Operating Temperature
TL494CN 16 DIP 0 ~ + 70°C
TL494CD 16 SOP
TL494
7/12/00 0.0m 001
Stock#DSxxxxxxxx
2000 Fairch il d Semiconduc tor International
LIFE SU PP ORT POL ICY
FAIRCHILD’S PRODUCTS AR E NOT AUTHORIZED FOR USE AS C RITICAL COMPONENTS I N LIFE S UPPORT DEVICE S
OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR
INTERNATIONAL. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body,
or (b) support or sustain life, and (c) whose failure to
perform when properly used in accordance with
instructions for use provided in the labeling, can be
reasonably expected to result in a significant injury of the
user.
2. A critical component in any component of a life support
device or syst em who se failure to perform can be
reasonably expected to cause the failure of the life support
device or system, or to affect its safety or effec tiv ene ss.
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