LX7167A Microchip

LX716 7A 3MHz, 2.4A Constant Frequency Hysteretic Synchronous Buck Regulator Features 2.4A Step-down Regulator Description Operational Input Supply Voltage Range: LX7167A is a step-down PWM Switching Regulator 3V-5.5V IC with integrated high side P-CH and low side N- CH MOSFETs. The IC operates using a hysteretic Integrated PMOS and NMOS control topology with a full load operating switching Load Current from Zero to 2.4A frequency of 3MHz allowing small output filter 3MHz Switching Frequency components while maintaining excellent dynamic SKIP Pulse to Improve Light Load load response. Efficiency The operational input voltage range of LX7167A is Input UVLO and OV Protection from 3V to 5.5V. The part has a Power Save Mode Enable Pin (PSM) that automatically transitions between PWM Power Good and PSM mode depending on the load current. This Internal Soft-start allows the converters efficiency to remain high when load current drops. There is a Power Good Cycle-by-Cycle Over Current Protection function to indicate the status of the IC. Hiccup Mode Operation Under FB UVLO In the shutdown mode, the ICs current consumption RoHS Compliant for Pb Free is reduced to less than 1A and the output capacitor is discharged. Applications Other features of the part are: a) Cycle-by-cycle HDD current limit followed by HICCUP mode which Set-Top Box reduces the overall power dissipation of the internal MOSFETs, b) thermal protection and internal digital LCD TVs soft start. Notebook/Netbook The LX7167A is available in a 2mm x 2mm 8 pin Routers exposed pad DFN package. Video Cards PC Peripherals PoE Powered Devices Smart Phone 100k PGOOD VIN 6 8 PG PVIN 0.47H VOUT C IN 2 SW 7 VCC R1 C1 C OUT 1% LX7167A 4 FB 5 R2 EN 1 PGND 1% GND 3 Figure 1 Typical Application of LX7167A June 2013 Rev. 1.0 www.microsemi.com 1 2013 Microsemi Corporation 67A xxxx 3MHz 2.4A Synchronous Buck Regulator Pin Configuration and Pinout 1 8PVIN PGND 7 2 VCC SW 6 GND 3 PG FB 4 5EN Figure 2 Pinout DFN 2mmx2mm 8L Top View Marking: First Line 67A Second Line YWWA (Year/Work Week/Lot Code) Ordering Information Ambient Temperature Type Package Part Number Packaging Type LX7167ACLD Bulk / Tube RoHS Compliant, -10C to 85C DFN 2mmx2mm 8L Pb-free LX7167ACLD-TR Tape and Reel Pin Description Pin Pin Description Number Designator PGND Ground pin for the power stage. 1 Switch-node pin. Connect the output inductor between this pin and output capacitor. 2 SW When the chip is DISABLED, the internal discharge resistor will be enabled to discharge the output capacitance. The current will flow into this pin. 3 GND Ground pin. Voltage feedback pin. Connect to the output terminal through a resistor divider network 4 FB to set the output voltage of the regulator to the desired value. Pull this pin higher than 1V will enable the controller. When pulled low, the IC will turn 5 EN off and the Internal discharge FET will turn on to discharge the output capacitor through the SW pin. Power-good pin. This is an open-drain output and should be connected to a voltage rail with an external pull-up resistor. During the power on, this pin switches from LOW to HI state when FB voltage reaches above the power good threshold and the 6 PG internal soft start has finished its operation. It will be pulled low when the FB falls below the power-good threshold minus the hysteresis. It will turn back on when the pull FB rises above the threshold. 7 VCC Analog input voltage terminal. Connect this pin to PVIN directly. Input voltage terminal of the regulator. A minimum of 10F, X5R type ceramic 8 PVIN capacitor must be connected as close as possible from this pin to PGND plane to insure proper operation. For good thermal connection, this PAD must be connected using thermal VIAs to the Power PAD GND plane and to the LAND pattern of the IC. 2