FT440AA

Fremont Micro Devices FT440 1.5MHz, 600mA Synchronous Step-Down Converter FEATURES DESCRIPTION ¾ High Efficiency - Up to 95% The FT440 is a 1.5MHz constant frequency, slope ¾ Guaranteed 600mA Output Current compensated current mode step down converter. ¾ 2.5V to 5.5V Input Voltage Range Capable of delivering 600mA output current over a ¾ 1.5MHz Constant Frequency Operation wide input voltage from 2.5V to 5.5V, the FT440 is ¾ No external Schottky Diode Needed ideally suited for single Li-Ion battery powered ¾ Adjustable Output Voltages From 0.6V to VIN application. ¾ Fixed Output Voltage Options Available ¾ 100% Duty Cycle Low-Dropout Operation The FT440 integrates a main switch and a ¾ 0.1ȝA Shutdown Current synchronous rectifier for high efficiency without an ¾ SOT23-5 Package external Schottky diode. The FT440 automatically turns off the synchronous rectifier to increase TYPICAL APPLICATIONS ¾ Cellular phones ¾ Blue Tooth Headsets ¾ Portable Audio Players ¾ Mobile Phones ¾ Wireless and DSL Modems ¾ Digital Still Cameras ¾ Portable Instruments ¾ Mp3 Player efficiency while enters discontinuous PWM mode. The FT440 can run at 100% duty cycle for low dropout operation, maximizing battery life in portable application. FT440 consumes less than 1uA when enter shutdown mode. The FT440 is available in a fixed output voltages of 1.5V, 1.8V, and 2.5V, and is also available in an adjustable output voltage version capable of generating output voltages from 0.6V to VIN .The FT440 is available in a 5-pin SOT23-5 package. www.fremontmicro.com Page 1 of 10 DS440-A3 Fremont Micro Devices FT440 TYPICAL APPLICATION CIRCUIT VIN 2.7~4.2V 4 V IN SW 3 1 EN Vout 1.8V C2 22pF FT440 C1 4.7uF L1 2.2uH V FB C3 5 GND 2 10uF R2 200K R1 100K Figure 1: Typical Application Circuit ABSOLUTE MAXIMUM RATINGS VIN to GND……………………………….……………………………………………………………-0.3V to 6V EN to GND..…………………………………………….……………………………….. ……-0.3V to (VIN+0.3) VFB to GND..…………………………………………………………………………………. -0.3V to (VIN+0.3) SW to GND………………….…………………………………………………………….……-0.3V to (VIN+0.3) Peak SW Sink and Source Current……………...……………………………………………….Internally Limited Junction to Ambient Thermal Resistance (©JA).…………………….……………………………………250ć/W Operating Temperature Range……………….……………………………………………………...-40ć to +85ć Junction Temperature………………………………………………………………………..….... -40ć to +150ć Storage Temperature Range …………………………..……………………………………….….-55ć to +150ć Lead Temperature (Soldering, 10sec) …………………………………………………………………...…...300ć Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. www.fremontmicro.com Page 2 of 10 DS440-A3 Fremont Micro Devices FT440 PIN COMFIGURATION Figure 2: Package Top View TERMINAL DEFINITION Pin Name Description Enable control input 1 EN 2 GND 3 SW Switching node, connecting to inductor 4 VIN Power input 5 VFB/Vout Ground Feedback node. VFB for adjustable version, and Vout for fixed output version Table 1 www.fremontmicro.com Page 3 of 10 DS440-A3 Fremont Micro Devices FT440 ORDERING INFORMATION FT440ķĸ Designator ķ Symbol A ADJ B 1.5V C 1.8V D 2.5V E 1.2V F 2.8V G 3.3V Designator ĸ Output Voltage Symbol Marking Rule a Marking Rule a b Marking Rule b Table 2 MARKING RULE a Part Number Top Mark Output Voltage )7$D 1AaXY ADJ )7%D 1BaXY 1.5V )7&D 1CaXY 1.8V )7'D 1DaXY 2.5V )7(D 1EaXY 1.2V )7)D 1FaXY 2.8V )7*D 1GaXY 3.3V Table 3 MARKING RULE b Part Number www.fremontmicro.com Top Mark Output Voltage )7$E A1XY ADJ )7%E A2XY 1.5V )7&E A3XY 1.8V )7'E A4XY 2.5V )7(E A5XY 1.2V )7)E A6XY 2.8V )7*E A7XY 3.3V Page 4 of 10 DS440-A3 Fremont Micro Devices FT440 Table 4 BLOCK DIAGRAM Figure 4: FT440 Block Diagram www.fremontmicro.com Page 5 of 10 DS440-A3 Fremont Micro Devices FT440 ELECTRICAL CHARACTERISTICS (VIN = VEN = 3.6V, TA = 25ÛC unless otherwise specified.) Parameter Symbol Input Voltage Range VIN Under Voltage Lockout Threshold VUVLO Test Conditions Min Typ 2.5 VIN rising 2.2 Max Unit 5.5 V 2.35 2.5 V Operating Supply Current VFB=0.5 or Vout=90% 300 450 uA Shutdown Supply Current VEN = 0V, VIN = 4.2V 0.1 1 uA Adjustable Version Regulation Voltage Fixed Output Regulation Voltage VFB VOUT TA = 25°C 0.588 0.6 0.612 0 < TA < 85°C 0.585 0.6 0.615 -40°C < TA < 85°C 0.582 0.6 0.618 FT440Ba / FT440Bb 1.455 1.5 1.545 FT440Ca / FT440Cb 1.746 1.8 1.854 FT440Da / FT440Db 2.425 2.5 2.575 FT440Ea / FT440Eb 1.164 1.2 1.236 FT440Fa / FT440Fb 2.716 2.8 2.884 FT440Ga / FT440Gb 3.2 3.3 3.4 0.4 Output Voltage Line Regulation VIN = 2.5V to 5.5V 0.04 Output Voltage Load Regulation IOUT = 0mA to 600mA 0.5 Inductor Current Limit ILIM Oscillator Frequency fSW VIN = 3.6V, VFB =0.5V or Vout=90% VFB=0.6 or Vout=100% V %/V % 0.85 1.1 1.35 A 1.2 1.5 1.8 MHz VFB=0 or Vout=0 400 KHz PMOS On Resistance RONP ISW = -100mA 0.36 0.5 ȍ NMOS On Resistance RONN ISW = 100mA 0.33 0.45 ȍ 1 uA 1 1.5 V 0.01 1 uA EN = 0, VIN = 5.5V, SW Leakage Current VSW = 5.5V or 0V EN Threshold VIH VIN = 2.5V to 5.5V EN Leakage Current IEN VIN = 5.5V, EN = VIN 0.3 Table 5 www.fremontmicro.com Page 6 of 10 DS440-A3 Fremont Micro Devices FT440 TYPICAL PERFORMANCE CHARACTERISTICS www.fremontmicro.com Page 7 of 10 DS440-A3 Fremont Micro Devices www.fremontmicro.com FT440 Page 8 of 10 DS440-A3 Fremont Micro Devices FT440 APPLICATION INFORMATION Figure5 below shows the typical application circuit with FT4402 fixed output versions. VIN 2.7~4.2V 4 VIN SW L1 2.2uH 3 Vout 1.8V FT440 C1 4.7uF 1 EN Vout C2 5 10uF GND 2 Figure 5: Typical Application Circuit with fixed output versions Inductor Selection Under normal operation, the inductor maintains continuous current to the output. Its value is chosen based on the desired ripple current. Large value inductors lower ripple current, and small value inductors result in higher ripple currents. The inductor value can be derived from the following equation: L Vout u (V IN  Vout ) , Where ̲IL is inductor ripple current. V IN u 'I L u f osc Input Capacitor Selection The input capacitor reduces input voltage ripple to the converter; a 4.7uF ceramic capacitor is recommended for most applications. Output Capacitor Selection The output capacitor is required to keep the output voltage ripple small and to ensure regulation loop stability. The output capacitor must have low impedance at the switching frequency. The output ripple ̲Vout approximately: 'VOUT # 'I L u ( ESR  1 ) 8 fC OUT Output Voltage Programming Figure1 above shows the typical application with FT4402 adjustable version. The external resistor sets the output voltage according to following equation: VOUT www.fremontmicro.com 0.6V u (1  Page 9 of 10 R2 ) R1 DS440-A3 Fremont Micro Devices FT440 SOT23-5 PACKAGE Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 1.050 1.250 0.041 0.049 A1 0.000 0.100 0.000 0.004 A2 1.050 1.150 0.041 0.045 b 0.300 0.500 0.012 0.020 c 0.100 0.200 0.004 0.008 D 2.820 3.020 0.111 0.119 E 1.500 1.700 0.059 0.067 E1 2.650 2.950 0.104 0.116 e 0.95 (BSC) 0.037 (BSC) e1 1.800 2.000 0.071 0.079 L 0.300 0.600 0.012 0.024 ș 0° 8° 0° 6° www.fremontmicro.com Page 10 of 10 DS440-A3