IR3821MTRPBF

PD-60331 IR3821MPbF SupIRBuck TM HIGHLY INTEGRATED 7A WIDE-INPUT VOLTAGE, SYNCHRONOUS BUCK REGULATOR Features • • • • • • • • • • • • • • Wide Input Voltage Range 2.5V to 21V Wide Output Voltage Range 0.6V to 12V Continuous 7A Load Capability 600kHz High Frequency Operation Programmable Over-Current Protection Programmable PGood Output Hiccup Current Limit Precision Reference Voltage (0.6V) Programmable Soft-Start Pre-Bias Start-up Thermal Protection Thermally Enhanced Package Small Size 5mmx6mm QFN Pb-Free (RoHS Compliant) Applications • • • • • • • • Distributed Point-of-Loads Server and Workstations Embedded Systems Storage Systems DDR Applications Graphics Cards Game Consoles Computing Peripheral Voltage Regulators Description The IR3821 SupIRBuckTM is an easy-to-use, fully integrated and highly efficient DC/DC regulator. The onboard switching controller and MOSFETs make the IR3821 a space-efficient solution, providing accurate power delivery for low output voltage applications. The IR3821 operates from a single 4.5V to 14V input supply and generates an output voltage adjustable from 0.6V to 0.75*Vin at loads up to 7A. A versatile regulator offering programmability of startup time, power good threshold and current limit, the IR3821’s fixed 600kHz switching frequency allows the use of small external components. The IR3821 also features important protection functions, such as Pre-Bias startup, hiccup current limit and thermal shutdown to provide the required system level security in the event of fault conditions. Fig. 1. Typical application diagram 11/04/08 1 PD-60331 IR3821MPbF ABSOLUTE MAXIMUM RATINGS (Voltages referenced to GND) • VIN Supply Voltage -0.3V to 24V • Vcc Supply Voltage -0.3V to 16V • Vc Supply Voltage -0.3V to 30V • SW -0.3V to 30V • PGood -0.3V to 16V • Fb,COMP,SS,Vsns -0.3V to 3.5V • OCSet 10mA • AGnd to PGnd -0.3V to +0.3V • Storage Temperature Range -65°C To 150°C • Operating Junction Temperature Range -40°C To 150°C • ESD Classification JEDEC, JESD22-A114 • Moisture Sensitivity Level JEDEC Level 3 @ 260oC Caution: Stresses beyond those listed under “Absolute Maximum Rating” may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to “Absolute Maximum Rating” conditions for extended periods may affect device reliability. PACKAGE INFORMATION 5mm x 6mm POWER QFN 10 12 11 VIN SW PGnd θJA = 35 o C / W θJ -PCB = 2 o C / W HG 13 VC 14 1 Vsns 15 AGnd 2 3 4 5 9 PGood 8 VCC 6 7 FB COMP AGnd AGnd SS OCSet Fig. 2: Package outline (Top view) ORDERING INFORMATION 11/04/08 PACKAGE DESIGNATOR PACKAGE DESCRIPTION PIN COUNT PARTS PER REEL M IR3821MTRPbF 15 4000 M IR3821MTR1PbF 15 750 2 PD-60331 IR3821MPbF Block Diagram Fig. 3. Simplified block diagram of the IR3821. 11/04/08 3 PD-60331 IR3821MPbF Pin Description Pin Name Description 1 Vsns PGood sense pin. Use two external resistors to program the power good threshold. 2 Fb 3 Comp Inverting input to the error amplifier. This pin is connected directly to the output of the regulator via resistor divider to set the output voltage and provide feedback to the error amplifier. Output of error amplifier. 4 AGnd Signal ground for internal reference and control circuitry. 5 AGnd Signal ground for internal reference and control circuitry. 6 SS/SD 7 OCSet Soft start / shutdown. This pin provides user programmable soft-start function. Connect an external capacitor from this pin to signal ground (AGnd) to set the start up time of the output voltage. The converter can be shutdown by pulling this pin below 0.3V. Current limit set point. A resistor from this pin to SW pin will set the current limit threshold. 8 VCC 9 PGood 10 PGnd 11 SW Switch node. This pin is connected to the output inductor 12 VIN Input voltage connection pin 13 HG 14 VC 15 AGnd This pin is connected to the high side Mosfet gate. Connect a small capacitor from this pin to switch node (SW). This pin powers the high side driver and must be connected to a voltage higher than input voltage. A minimum of 0.1uF high frequency capacitor must be connected from this pin to the power ground (PGnd). Signal ground for internal reference and control circuitry. This pin provides biasing voltage for the internal blocks of the IC. It also powers the low side driver. A minimum of 0.1uF, high frequency capacitor must be connected from this pin to power ground (PGnd). Power Good status pin. Output is open collector. Connect a pull up resistor from this pin to Vcc. Power Ground. This pin serves as a separated ground for the MOSFET drivers and should be connected to the system’s power ground plane. Pins 4, 5 and 15 need to be connected together on system board. 11/04/08 4 PD-60331 IR3821MPbF Recommended Operating Conditions Symbol Vin Vcc Vc Vo Io Note1 Tj Definition Input Voltage Supply Voltage Supply Voltage Output Voltage Output Current Junction Temperature Min Max 2.5 4.5 Vin + 5V 0.6 0 -40 21 14 28 12 7 125 Units V A C o Electrical Specifications Unless otherwise specified, these specification apply over Vin=Vcc=Vc=12V, 0oC