NX2154

Evaluation board available. NX2154/2154A 300kHz SYNCHRONOUS PWM CONTROLLER PRELIMINARY DATA SHEET Pb Free Product DESCRIPTION The NX2154/2154A controller IC is a synchronous Buck controller IC designed for step down DC to DC converter applications. It is optimized to convert bus voltages from 2V to 40V to outputs as low as 0.8V voltage. The NX2154/2154A operates at fixed 300kHz. The NX2154/2154A employs fixed loss-less current limiting by sensing the Rdson of synchronous MOSFET followed by hiccup feature.NX2154A has higher current limit threshold than NX2154. Feedback under voltage also triggers hiccup. 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 comp pin. FEATURES n n n n n n Bus voltage operation from 2V to 40V Fixed 300kHz voltage mode controller Internal Digital Soft Start Function Prebias Startup Less than 50 nS adaptive deadband Current limit triggers hiccup by sensing Rdson of Synchronous MOSFET n No negative spike at Vout during startup and shutdown n Pb-free and RoHS compliant APPLICATIONS n n n n n Graphic Card on board converters Memory Vddq Supply in mother board applications On board DC to DC such as 5V to 3.3V, 2.5V or 1.8V Hard Disk Drive Set Top Box TYPICAL APPLICATION Vin +5V MBR0530T1 1uF 50ME180WX Vin +33V 1uF 5 1 Vcc 7 BST 0.1uF 2 M1A STM6920 15uH HI=SD M3 12nF 82pF 13.3k 6 NX2154 Comp Hdrv SW Ldrv 8 M1B Vout +5V,3A 6ME1000WG(1000uF,30mohm) Fb Gnd 3 4 1k 191 Figure1 - Typical application of 2154 ORDERING INFORMATION Device NX2154CSTR NX2154ACSTR Rev.1.2 02/26/07 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 NX2154/2154A (NOTE1) Vcc to GND & BST to SW voltage ................... 6.5V BST to GND Voltage ...................................... 50V 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 SYM VREF Test Condition 4.5V