CMOS IC For Switching Power Supply Control FA3635P FA3635P ■ Description ■ Dimensions, mm FA3635P is a CMOS IC which includes low on-resistance power MOSFET for PWM-type switching power supply control. This IC achieves high efficiency DC-DC converter and it is suitable for buck converter or inverting converter with high input voltage of 10V to 50V. Á DIP-8 8 6.5 5 ■ Features ■ Applications 9.4 1.5 4 3.1min 4.5max 1 3.4 • Built-in low on-resistance Pch power MOSFET 50V/1.1Ω(typ.)/1A(peak) • Wide range of 10V to 50V for input voltage • 1.2mA low operating current as a Power IC • Latch-mode short-circuit protection function • Built-in over-temperature protection Tj =125°C (min.) 0.5±0.1 2.54±0.25 +0.1 5 –0.0 0.25 7.6 0~15 ˚ 5˚ 0~1 • Power supply for general equipment ■ Block diagram Pin No. Pin symbol Description 1 Power supply 2 VCC FB 3 IN Inverting input to error amplifier 4 GND Ground 5 GND Ground 6 REF Reference voltage 7 CS OUT Capacitor for soft-start 8 1 Error amplifier output Output FA3635P ■ Absolute maximum ratings ■ Recommended operating conditions Item Symbol Rating Unit Item Symbol Min. Max. Unit Supply voltage VCC VIN Pd 50.0 V Supply voltage 10.0 45.0 V 5.5 V REF terminal by-pass capacitor 1.1 W VCC terminal by-pass capacitor VCC CREF CO Junction temperature Tj 125 °C Operating temperature Top Tstg –20 to +85°C °C –40 to +150 °C Error amplifier input voltage Total Power dissipation (Ta = 25°C) Storage temperature 0.047 0.22 µF 470 µF ■ Electrical characteristics (Ta=25°C, VCC=44V, CREF=0.1µF) Reference voltage section Item Symbol Test condition Min. Typ. Max. Unit terminal Voltage VREG CREF=0.1µF 3.00 3.12 3.24 V Item Symbol Test condition Min. Typ. Max. Unit Oscillation frequency fOSC fdV fdT 70 81 100 kHz VCC=10 to 45V Ta=–20 to +85°C ±1 ±3 % ±3 ±5 % Item Symbol Test condition Max. Unit Input common mode voltage range VICOM AVOL 2.5 V Oscillator section Frequency change with supply voltage Frequency change with temperature Error amplifier section Open-loop gain Output sink current fT IFBL Output source current IFBH Reference Voltage Vref Unity-gain bandwidth Min. Typ. 0.2 55 Voltage follower 3.0 dB 1.0 MHz 3.8 mA VFB=Vref+0.05V –140 –100 µA 0.97 1.00 1.03 V Voltage follower VFB=Vref–0.05V Voltage follower VCC=10 to 45V Ta=–20 to +85°C VFB 0 VFB 100 Duty cycle=0% 0.5 0.6 0.7 V Duty cycle=100% 2.3 2.5 2.7 V Item Symbol Test condition Min. Typ. Max. Unit Input threshold voltage (Pin 7) VCS 0 VCS 100 ICS Duty cycle=0% 0.5 0.6 0.7 V Duty cycle=100% 2.3 2.5 2.7 V –2.8 –2.2 –1.6 µA Item Symbol Test condition Operating voltage VUVLO Input threshold voltage (Pin 2) Soft-start circuit section Charge current Undervoltage lockout circuit section Min. Typ. Max. Unit 5.0 6.1 8.5 V 2 FA3635P Overheat protection section Item Symbol Operating temperature TOH ∆TOH Hysteresis width Test condition Min. Typ. Max. Unit 125 135 145 °C 45 50 55 °C Output section Item Symbol Test condition Typ. Max. Unit Voltage drop VDROP IOUT =1.0A IOUT =0.7A Min. 1.1 1.4 V 0.7 0.9 IOUT =0.1A 0.1 0.2 1.75 2.0 A Typ. Max. Unit 0.9 4.0 mA IOLMT Peak current 1.0 Item Symbol Test condition Min. Operating current ICC Out pin open, VCC=44V Overcurrent limit Overall device Duty cycle=100% ■ Characteristic curve Á Thermal characteristic 1.6 1.4 LOSS [W] 1.2 1 0.8 0.6 0.4 0.2 0 0 50 100 Ambient temperature [°C] Thermal resistance : θj-c(Junction to case) = 30°C/W θj-a(Junction to air) = 90°C/W 3 150 FA3635P ■ Characteristic curves (Ta=25°C) Output duty cycle vs. CS terminal voltage (VCS ) 100 100 90 90 80 80 Output duty cycle [%] Output duty cycle [%] Output duty cycle vs. FB terminal voltage (VFB) 70 60 50 40 30 70 60 50 40 30 20 20 10 10 0 0 0.5 1 1.5 2 2.5 0 3 0 0.5 1 1.5 VFB [V] 2 2.5 3 VCS [V] Oscillation frequency (fOSC ) vs. ambient temperature (Ta) Reference voltage (V REF) vs. ambient temperature (Ta) 100 1.05 1.04 95 1.03 VREF [V] fosc [kHz] 90 85 1.02 1.01 1 80 0.99 75 0.98 70 20 20 0 40 60 80 0.97 20 100 40 20 0 60 80 100 Ta [°C] Ta [°C] Output voltage (VOUT) vs. output current (IOUT) Supply current (ICC ) vs. supply voltage (VCC) 2 1.8 1.6 1.5 1.2 Icc [mA] VCC– VOUT [V] 1.4 1 0.8 1 0.6 0.5 0.4 0.2 0 0 0.2 0.4 0.6 IOUT [A] 0.8 1 0 0 10 30 20 40 50 Vcc [V] 4 FA3635P Error amplifier voltage gain (AV)/ phase (θ) vs. frequency (f) Condition: Open loop 180 160 140 120 Av [dB] [deg] 100 Phase 80 60 Voltage gain 40 20 0 – 20 – 40 10 100 1K 10K 100K 1M 10M ƒ [HZ] ■ Application circuit Parts tolerances characteristics are not defined in the circuit design sample shown above. When designing an actual circuit for a product, you must determine parts tolerances and characteristics for safe and economical operation. 5