www.fairchildsemi.com TL494 SMPS Controller Features Description * 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 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 control 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 (c)2000 Fairchild Semiconductor International TL494 Absolute Maximum Ratings Parameter Supply Voltage Collector Supply Voltage Output Current 2 Symbol Value Unit VCC 42 V VC 42 V IO 250 mA Amplifier Input Voltage VIN VCC + 0.3 V Power Dissipation (TA = 25C) PD 1 (TL494CN) 0.9 (TL494CD) W Operating Temperature Range TOPR 0 ~ +70 C Storage Temperature Range TSTG -65 ~ + 150 C TL494 Electrical Characteristics (VCC = 20V, f = 10KHz, TA = 0C to + 70C, unless otherwise specified) Parameter Symbol Conditions Min. Typ. Max. Unit 4.75 5.0 5.25 V - 2.0 25 mV TA = 0C to 70C - 0.01 0.03 %/C IREF = 1mA to 10mA - 1.0 15 mV 10 35 50 mA REFERENCE SECTION Reference Output Voltage Line Regulation Temperature Coefficient of VREF Load Regulation Short-Circuit Output Currnet VREF VREF VREF/T VREF ISC IREF = 1mA VCC = 7V to 40V VREF = 0V OSCILLATOR SECTION f CT = 0.01F, RT = 12K - 10 - KHz f/T CT = 0.01F, RT = 12K - - 2 % IBIAS VCC = 15V, 0VV45.25V - -2.0 -10 A 45 - - % Zero Duty Cycle - 3.0 3.3 Max. Duty Cycle 0 - - Oscillation Frequency Frequency Change with Temperature DEAD TIME CONTROL SECTION Input Bias Current Maximum Duty Cycle Input Threshold Voltage D(MAX) VITH VCC = 15V, V4 = 0V O.C Pin = VREF V 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 A 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 Input Sink Currnet ISINK V3=0.7V - 4 4.5 V -0.3 -0.7 - mV OUTPUT SECTION Output Saturation Voltage Common Emitter VCE(SAT) VE = 0, IC = 200mA - 1.1 1.3 Common Collector VCC(SAT) VC = 15V, IE = -200mA - 1.5 2.5 Collector Off-State Currnet IC(OFF) VCC = 40V, VCE = 40V - 2 100 Emitter Off-State Current IE(OFF) VCC = VC = 40V, VE = 0 - - -100 ICC Pin 6 = VREF, VCC = 15V - 6 10 mA - V A TOTAL DEVICE Supply Current OUTPUT SWITCHING CHARACTERISTIC Rise Time tR - - - - Common Emitter - - - 100 200 Common Collector - - - 100 200 Fall Time tF - - - - Common Emitter - - - 25 100 Common Collector - - - 40 100 ns ns 3 TL494 Typical Application Pulse Width Modulated Step-down Converter TL494 4 TL494 Mechanical Dimensions Package 16-DIP #9 7.62 0.300 2.54 0.100 1.50 0.10 0.059 0.004 #8 0.46 0.10 0.018 0.004 #16 19.80 MAX 0.780 #1 19.40 0.20 0.764 0.008 ( 0.81 ) 0.032 6.40 0.20 0.252 0.008 3.25 0.20 0.128 0.008 5.08 MAX 0.200 0.38 0.014 MIN 3.30 0.30 0.130 0.012 +0.10 0~15 0.25 -0.05 +0.004 0.010 -0.002 5 TL494 Mechanical Dimensions (Continued) Package 16-SOP 0.05 0.002 0.51 ) 0.020 MIN #9 0.70 0.20 0.0275 0.008 6 1.27 0.050 1.80 MAX 0.071 8 MAX0.10 MAX0.004 3.95 0.20 0.156 0.008 0~ +0.10 0.20 -0.05 +0.004 0.008 -0.002 6.00 0.30 0.236 0.012 5.72 0.225 +0.10 0.406 -0.05 +0.004 0.016 -0.002 #8 9.90 0.20 0.39 0.008 #16 10.30 MAX 0.405 #1 ( 1.55 0.10 0.061 0.004 TL494 Ordering Information Product Number Package TL494CN 16 DIP TL494CD 16 SOP Operating Temperature 0 ~ + 70C 7 TL494 LIFE SUPPORT POLICY FAIRCHILD'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES 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 system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. www.fairchildsemi.com 7/12/00 0.0m 001 Stock#DSxxxxxxxx 2000 Fairchild Semiconductor International