Advanced Monolithic Systems AMS4122 SINGLE 4A/DUAL 2A BUCK CONVERTER IN SO8 RoHS compliant FEATURES APPLICATIONS • 2 Independent Asynchronous Buck Converters in SO-8 • Internally compensated • Built in soft start • Enable with Zero current shut down • 400KHz switching per output • Interleaved oscillator to reduced supply ripple • Simply re-configures to 2 phase single output • Up to 4A output in 2 phase mode • Independent hiccup current limit • Audio Power Amplifiers • Portable (Notebook) Computers • Point of regulation for high performance electronics • Consumer Electronics • Desktop Computers • LCD TVs and LCD monitors • Distributed Power Systems • Battery Chargers • Pre-Regulator for Linear Regulators GENERAL DESCRIPTION AMS4122 is a dual switching regulator capable to deliver up to 2A for each channel. Internally Compensated internal Soft Start makes AMS4122 one of the simplest and easiest switching regulators to use with the minimum external components. Each regulator has independent hiccup current limit. The Enable pin turns both devices on when a voltage of 2.5V or higher it is applied to EN pin. Since both devices share one single package the thermal protection turns off both devices when the die temperature exceeds approximately 135°C. Both regulators are adjustable using a 0.600V reference for low output voltage settings. The oscillators are 180° phase to each other to reduce the ripples on the input power supply and minimize the power dissipation on the package. The device can be easily configured for Two Phase single output switching regulator capable of 5A output load. By applying a 2.5V or greater on feedback pin of the second switching regulator the device enters in Two Phase Mode. The first benefit of having a Two Phase device is reducing the output ripples by a factor of four as the single phase. The second benefit is higher output current capability at overall low cost. AMS4122 combined with AMS4123 (2A Switching Regulator + 1A LDO in SO-8) makes complete solution for LCD TV power requirements. ORDERING INFORMATION Package Type SOIC EDP AMS4122S TEMP. RANGE PINCONNECTIONS -25°C to 125°C TYPICAL APPLICATION 8L SOIC SO Package (S) SW 2 1 8 SW 1 P2VIN 2 7 P1+AVIN GND 3 6 EN F/ B 2 4 5 F/ B 1 Top View Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723 AMS4122 PIN DESCRIPTION Pin Number NAME DESCRIPTION 1 SW2 This connects the inductor the Internal Switch2 2 P2VIN Input Power Pin for SW2 from unregulated power supply 3 GND Ground Pin connected to PCB ground plane. This pin is also the ground for internal voltage reference. 4 F/B2 Feedback2. A resistor network of two resistors is used to set-up the output voltage connected between Output2 to GND. The node between the two resistors is connected to Feedback2 pin. In Two Phase Mode F/B2 should be connected to a voltage 2.5V or higher 5 F/B1 Feedback1. A resistor network of two resistors is used to set-up the output voltage connected between Output1 to GND. The node between the two resistors is connected to Feedback1 pin. 6 EN Enable. A voltage greater than 2.5V at this pin enables both devices operation. 7 P1+AVIN Input Power Pin for SW1 and Analog Input Voltage that powers up the chip 8 SW1 This connects the inductor the Internal Switch1 RECOMMANDED OPERATING CONDITIONS: The minimum input voltage should be 4.5V, however the device will function as low as 4.0V. The maximum operating voltage should be 20V, the device will work at 22V but the switching loss is higher. The best performance is at 1.5A output load per channel; however it works well with 2A load per channel. The minimum supply voltage is Vout +1Vfor 1A load and Vout +1.1V for 2A load but must be higher than 4.2V. There is an internal UVLO that will turn off the device if the input voltage is below 4.0V. When the input voltage exceeds 12V the output load current should be maintain below 1.5A, due to switching loss the device will have lower performance. Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723 AMS4122 ABSOLUTE MAXIMUM RATINGS VIN F/B EN 4.0V to 20V -0.3 to +12.0V -0.3V to +20V Junction Temperature Storage Temperature Lead temperature +150ºC -65ºC to +150ºC 260ºC ELECTRICAL CHARACTERISTICS Electrical Characteristics at TA= 25 °C and VIN=12V (unless otherwise noted). PARAMETER TEST CONDITIONS Feedback voltage F/B-1 and F/B-2 Full Load Output Current Feedback2 (note 1) Measured on each channel (note 4) Two Phase Mode Phase Shift between Outputs Dual Output Mode Current Limit Per Output Phase current match Oscillator Frequency Dual Phase Single Output Mode Min. AMS4122 Typ. Max. 0.590 0.6 0.610 V 2 A 171 Units 1.3 2.5 V 180 189 <º 4 Note(2) 360 10 400 Maximum Duty Cycle A 440 % KHz 100 % Enable Threshold 2.5 V Enable Hysteresis 120 mV Enable Pull-up Current Under Voltage Lockout Threshold Rising Under Voltage Lockout Threshold Hysteresis Supply Current (Shutdown) 0.7 µA 3.5 V VEN ≤ 0.4V 150 100 mV nA Supply Current (Quiescent) VEN ≥ 2.8V; VFB = 1.5V 1.5 Thermal Shutdown Total Power dissipation 135 Note (3) 2.5 1.9 mA °C W Notes: 1) When a 1.3V or greater is applied to F/B2, the device enters in Two Phase Mode of operation. 2) The oscillators for each switching regulator are shifted by 180º of each-other to accommodate dual phase operation and reduce the ripples in the input power supply. 3) The power dissipation for SO-8 EDP package is limited to 2.5W rated at 25°C ambient temperatures. The thermal resistance Junction to Case is 45°C/W. Total power dissipation for both switching regulators should be taken in consideration when calculating the output current for each regulator. 4) The load current is specified for two output configuration. The output load it is dependent of the output voltage. The total output power should be kept under 6W/channel to avoid thermal shut-down. Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723 AMS4122 TYPICAL PERFORMANCE WAVEFORM AMS4122 DUAL OUTPUT Vin=12V Low Output Current DUAL OUTPUT Vin=7V Full Load Output Current AMS4122 DUAL OUTPUT Vin=12V Full Load Output Current DUAL PHASE Full Load Output Current Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723 AMS4122 TYPICAL APPLICATION 2 Phase Single Output Application VOUT = VREF (1+ R1/R2) L1 10µ VIN P1+A VIN SW 1 V OUT L2 10µ on off P2 VIN SW 2 EN F/B 1 0 F/B 2 4A @ 5V 2x22µF VEN C1 C2 1n R1 22µ 7.333K R2 D1 MBR330 D2 MBR330 1K GND Dual Output Application VOUT1 = VREF (1+ R1/R2) VOUT2 = VREF (1+ R3/R4) Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723 AMS4122 PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted. 8 LEAD SOIC PLASTIC PACKAGE (S) 0.189-0.197* (4.801-5.004) 8 7 6 8 5 0.228-0.244 (5.791-6.197) 0.123 (3.12) 0.137 (3.48) 7 6 5 0. 150-0.157** (3.810-3.988) 1 2 3 1 4 2 3 4 0.010-0.020 x 45° (0.254-0.508) 0.053-0.069 (1.346-1.752) 0.004-0.010 (0.101-0.254) 0.014-0.019 (0.355-0.483) 0.024(0.61) 0.090 (2.28) 0.102 (2.59) 0.008-0. 010 (0.203-0.254) 0.050 (1.270) TYP 0°-8 ° TYP 0.016-0.050 (0.406-1.270) S (SO- 8 ) AMS DRW# 042293 *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE 0.050(1.27) 0.063(1.60) **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 0.105(2.67) 0.213(5.41) 0.138 (3.50) RECOMMENDED LAYOUT PATTERN Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723