MIC25400YML-TR

MIC25400 2A Dual Output PWM Synchronous Buck Regulator IC General Description Features The MIC25400 is a synchronous PWM dual output step down converter with internal 2A high-side switches. The MIC25400 has an integrated low-side gate driver for synchronous step-down conversion by connecting an external N-channel MOSFET to achieve high efficiencies in low duty-cycle applications. The IC’s switching frequency is 1MHz. A patented control scheme allows the use of a wide range of output capacitance from small ceramic capacitors to large electrolytic types with only one compensation component. A 2% output voltage tolerance over the temperature range allows the maximum level of system performance. The MIC25400 power good signal allows full control for sequencing the output voltages with minimum external components. • • • • • • • • • • • • • • • An adjustable current limit allows the use of smaller inductors in lower current applications. The MIC25400 is available in the ePad 24-pin 4mm × 4mm ® MLF package, and has an operating junction temperature range of –40°C to +125°C. Datasheets and support documentation are available on Micrel’s web site at: www.micrel.com. 4.5V to 13.2V input voltage range Adjustable output voltages down to 0.7V 2A per channel 180° out-of-phase operation Low-side driver for synchronous operation 2% output voltage accuracy (over temperature) 1MHz switching frequency Output voltage sequencing Programmable maximum current-limit Power good output Ramp Control™ provides soft-start Low-side current sensing allows very low duty-cycle Works with ceramic output capacitors 24-pin 4mm × 4mm MLF package Junction temperature range of –40°C to +125°C Applications • Multi-output power supplies with sequencing • DSP, FPGA, CPU, and ASIC power supplies • Telecom and networking equipment, servers Typical Application VIN 6.0V – 13.2V 22µF VIN < 6.0V 10k 1.0µF PVDD PG1 PG1 10k VIN PG2 VIND1 VIND2 BST1 BST2 PG2 10µF 10µF 20 10nF 4.7µH VOUT1 3.3V/2A 3.3nF 10nF 4.7µH MIC25400 604 1.0k 20 22µF SW1 SW2 CS1 CS2 LSD1 PGND1 FB1 VOUT2 1.2V/2A 604 22µF LSD2 1.5nF FB2 EN/DLY1 EN/DLY2 VEN1 1.0k PGND2 VEN2 1.4k 274 10nF 68pF COMP1 COMP2 AGND 47pF 10nF MIC25400 Dual Output Buck Converter Ramp Control is a trademark of Micrel, Inc. MLF and MicroLead Frame are registered trademarks of Micrel, Inc. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com July 11, 2013 Revision 1.4 Micrel, Inc. MIC25400 Ordering Information Part Number MIC25400YML Voltage Switching Frequency Temperature Range Package Lead Finish Adjustable 1MHz -40°C to +125°C 24-Pin 4mm × 4mm MLF Pb-Free Pin Configuration 24-Pin 4mm × 4mm MLF (ML) (Top View) Pin Description Pin Number Pin Name Pin Description 1 BST1 Boost 1 (Input): Provides voltage for high-side internal MOSFET for channel 1. Connect a 0.01µF capacitor from SW1 to BST1 pin and a diode-to-PVDD. 2 LSD1 Low-Side Drive 1 (Output): External low-side N-Channel MOSFET driver. Use 4.5V rated MOSFETs. 3 PGND1 4 CS1 Current Sense 1 (Input): Place a resistor from SW1 to this pin to program the current limit point from 0.5A to 2.7A. 5 PG1 Power Good 1 (Output): Open drain. Device is in the OFF state. i.e., high when output is within 90% of regulation. Power Ground 1 (Input). Enable/Delay 1 (Input): This pin can be used to disable VOUT1. When used to disable VOUT1, this pin must be pulled down to ground in less than 1µs for proper operation. It is also used for soft-start of the output. Soft-start capacitor range is 4.7nF to 22nF (see the Functional Description section for additional information). 6 EN/DLY1 7 COMP1 Compensation 1 (Input): Pin for external compensation, Channel 1. 8 FB1 Feedback 1 (Input): Input to Ch1 error amplifier. Regulates to 0.7V. 9 NC No Connect. 10 AGND July 11, 2013 Analog Ground (Input): Control section ground. Connect to PGND. 2 Revision 1.4 Micrel, Inc. MIC25400 Pin Description (Continued) Pin Number Pin Name 11 FB2 12 COMP2 Pin Description Feedback 2 (Input): Input to Channel 2 error amplifier. Regulates to 0.7V. Compensation 2 (Input): Pin for external compensation, Channel 2. Enable/Delay 2 (Input): This pin can be used to disable VOUT2. When used to disable VOUT2, this pin must be pulled down to ground in less than 1µs for proper operation. It is also used for soft-start of the output. Soft-start capacitor range is 4.7nF to 22nF (see the Functional Description section for additional information). 13 EN/DLY2 14 PG2 Power Good 2 (Output) Open drain. Device is in the OFF state. i.e., high when output is within 90% of regulation 15 CS2 Current Sense 2 (Input) Place a resistor from SW2 to this pin to program the current-limit point from 0.5A to 2.7A 16 PGND2 17 LSD2 Low-Side Drive 2 (Output): External low-side N-Channel MOSFET driver. Use 4.5V rated MOSFETs. 18 BST2 Boost 2 (Input): Provides voltage for high-side internal MOSFET for Channel 2. Connect a 0.01µF capacitor from SW2 to BST2 pin and a diode-to-PVDD. 19 SW2 Switch Node 2 (Output): Source of internal high-side power MOSFET. 20 VIND2 Supply voltage (Input): For the drain of internal high-side power MOSFET 4.5V to 13.2V. 21 PVDD 5V Internal Linear Regulator (Output): PVDD is the external MOSFET gate drive for LSD1 and LSD2 and an internal supply bus for the IC. Connect to an external 1µF bypass capacitor. When VIN is