AMS494 Features PIN CONFIGURATION • 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 AMS494 is used for the control circuit of the PWM switching regulator. The AMS494 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. 1B 1 16 1C 2B 2 15 2C 3B 3 14 3C 4B 4 13 4C 5B 5 12 5C 6B 6 11 6C 7B 7 10 7C E 8 9 (Top View) Internal Block Diagram 1 Advanced Monolithic Systems http://www.ams-semitech.com COM AMS494 Absolute Maximum Ratings Parameter Supply Voltage Collector Supply Voltage Output Current Symbol Value Unit VCC 42 V VC 42 V IO 250 mA Amplifier Input Voltage VIN VCC + 0.3 V Power Dissipation (TA = 25°C) PD Operating Temperature Range TOPR 0 ~ +70 °C Storage Temperature Range TSTG -65 ~ + 150 °C 1 (AMS494CN) 0.9 (AMS494CD) 2 Advanced Monolithic Systems http://www.ams-semitech.com ｈｔｔｐ：／／ｗｗｗ．ｔｃ－ｉｃ．ｃｏｍ W AMS494 Electrical Characteristics (VCC = 20V, f = 10KHz, TA = 0°C to + 70°C, unless otherwise specified) Parameter Symbol Conditions Min. Typ. Max. Unit 4.75 5.0 5.25 V - 2.0 25 mV TA = 0°C to 70°C - 0.01 0.03 %/°C IREF = 1mA to 10mA - 1.0 15 mV 10 35 50 mA REFERENCE SECTION Reference Output Voltage VREF ∆VREF Line Regulation Temperature Coefficient of VREF ∆VREF/∆T ∆VREF Load Regulation Short-Circuit Output Currnet ISC IREF = 1mA VCC = 7V to 40V VREF = 0V OSCILLATOR SECTION Oscillation Frequency Frequency Change with Temperature f CT = 0.01µF, RT = 12KΩ - 10 - KHz ∆f/∆T CT = 0.01µF, RT = 12KΩ - - 2 % IBIAS VCC = 15V, 0V≤V4≤5.25V - -2.0 -10 µA 45 - - % Zero Duty Cycle - 3.0 3.3 Max. Duty Cycle 0 - - DEAD TIME CONTROL SECTION Input Bias Current Maximum Duty Cycle D(MAX) Input Threshold Voltage 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 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 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 µA 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 3 Advanced Monolithic Systems http://www.ams-semitech.com ns ns AMS494 Typical Application Pulse Width Modulated Step-down Converter AMS494 4 Advanced Monolithic Systems http://www.ams-semitech.com ｈｔｔｐ：／／ｗｗｗ．ｔｃ－ｉｃ．ｃｏｍ AMS494 Mechanical Dimensions Package 16-DIP #9 7.62 0.300 2.54 0.100 3.25 ±0.20 0.128 ±0.008 0.38 0.014 MIN 3.30 ±0.30 0.130 ±0.012 5.08 MAX 0.200 +0.10 0~15° 0.25 –0.05 +0.004 0.010 –0.002 5 Advanced Monolithic Systems http://www.ams-semitech.com 1.50 ±0.10 0.059 ±0.004 #8 19.40 ±0.20 0.764 ±0.008 #16 19.80 MAX 0.780 #1 0.46 ±0.10 0.018 ±0.004 ( 0.81 ) 0.032 6.40 ±0.20 0.252 ±0.008 AMS494 Mechanical Dimensions (Continued) Package 16-SOP 0.05 0.002 0.51 ) 0.020 MIN #9 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 0.70 ±0.20 0.0275 ±0.008 6 Advanced Monolithic Systems http://www.ams-semitech.com ｈｔｔｐ：／／ｗｗｗ．ｔｃ－ｉｃ．ｃｏｍ AMS494 Ordering Information Product Number Package AMS494CN 16 DIP AMS494CD 16 SOP Operating Temperature 0 ~ + 70°C 7 Advanced Monolithic Systems http://www.ams-semitech.com