NX2124CSTR

Evaluation board available. NX2124/2124A 300kHz SYNCHRONOUS PWM CONTROLLER PRELIMINARY DATA SHEET Pb Free Product DESCRIPTION FEATURES n n n n n n Bus voltage operation from 2V to 25V The NX2124/2124A controller IC is a synchronous Buck Fixed 300kHz voltage mode controller controller IC designed for step down DC to DC conInternal Digital Soft Start Function verter applications. It is optimized to convert bus voltPrebias Startup ages from 2V to 25V to outputs as low as 0.8V voltage. Less than 50 nS adaptive deadband The NX2124/2124A operates at fixed 300kHz, employs Current limit triggers hiccup by sensing Rdson of fixed loss-less current limiting by sensing the Rdson of Synchronous MOSFET synchronous MOSFET followed by hiccup feature. n No negative spike at Vout during startup and NX2124A has higher current limit threshold than NX2124. shutdown Feedback under voltage also triggers hiccup. n Pb-free and RoHS compliant Other features of the device are: 5V gate drive, Adaptive deadband control, Internal digital soft start, Vcc undervoltage lock out and shutdown capability via the n Graphic Card on board converters comp pin. n Memory Vddq Supply in mother board applications n On board DC to DC such as 5V to 3.3V, 2.5V or 1.8V n Hard Disk Drive n Set Top Box APPLICATIONS TYPICAL APPLICATION Vin +5V C4 100uF L2 1uH C5 1uF D1 MBR0530T1 1 Cin 280uF 18mohm R5 10 5 C3 1uF Vcc 7 BST Hdrv 2 C6 0.1uF M1 L1 1.5uH HI=SD M3 NX2124 COMP R4 37.4k C7 27pF C2 2.2nF 6 SW Ldrv 8 4 M2 R1 4k R2 10k Co 2 x (1500uF,13mohm) Vout +1.8V 9A FB Gnd 3 C1 4.7nF R3 8k Figure1 - Typical application of 2124 ORDERING INFORMATION Device NX2124CSTR NX2124ACSTR Rev.1.8 02/28/08 Temperature 0 to 70oC 0 to 70o C Package SOIC-8L SOIC-8L Frequency 300kHz 300kHz OCP Threshold 360mV 540mV Pb-Free Yes Yes 1 NX2124/2124A (NOTE1) Vcc to GND & BST to SW voltage ................... 6.5V BST to GND Voltage ...................................... 40V SW to GND Voltage .......................................-3V to 35V Storage Temperature Range ............................. -65oC to 150oC Operating Junction Temperature Range ............. -40oC to 125oC NOTE1: Stresses above those listed in "ABSOLUTE MAXIMUM RATINGS", may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. ABSOLUTE MAXIMUM RATINGS PACKAGE INFORMATION 8-PIN PLASTIC SOIC (S) θJA ≈ 130o C/W BST 1 HDrv 2 Gnd 3 LDrv 4 8 SW 7 Comp 6 Fb 5 Vcc ELECTRICAL SPECIFICATIONS Unless otherwise specified, these specifications apply over Vcc = 5V, and TA = 0 to 70oC. Typical values refer to TA = 25oC. Low duty cycle pulse testing is used which keeps junction and case temperatures equal to the ambient temperature. PARAMETER Reference Voltage Ref Voltage Ref Voltage line regulation Supply Voltage(Vcc) VCC Voltage Range VCC Supply Current (Static) VCC Supply Current (Dynamic) Supply Voltage(VBST) VBST Supply Current (Static) VBST Supply Current (Dynamic) Under Voltage Lockout VCC-Threshold VCC-Hysteresis Rev.1.8 02/28/08 SYM VREF Test Condition 4.5V