MIC26601 28V, 6A Hyper Speed Control Synchronous DC/DC Buck Regulator SuperSwitcher II General Description Features The Micrel MIC26601 is a constant-frequency, synchronous Hyper Speed Control architecture enables buck regulator featuring a unique adaptive on-time control - High Delta V operation (V = 28V and V = 0.8V) IN OUT architecture. The MIC26601 operates over an input supply - Small output capacitance range of 4.5V to 28V and provides a regulated output of up to 4.5V to 28V voltage input 6A of output current. The output voltage is adjustable down to 6A output current capability, up to 95% efficiency 0.8V with a guaranteed accuracy of 1%, and the device Adjustable output from 0.8V to 5.5V operates at a switching frequency of 600kHz. 1% feedback accuracy Micrels Hyper Speed Control architecture allows for ultra- Any Capacitor stable - zero-to-high ESR fast transient response while reducing the output capacitance and also makes (High V )/(Low V ) operation possible. IN OUT 600kHz switching frequency This adaptive t ripple control architecture combines the ON No external compensation advantages of fixed-frequency operation and fast transient Power Good (PG) output response in a single device. Foldback current-limit and hiccup mode short-circuit The MIC26601 offers a full suite of protection features to protection ensure protection of the IC during fault conditions. These Supports safe startup into a pre-biased load include undervoltage lockout to ensure proper operation 40 C to +125 C junction temperature range under power-sag conditions, internal soft-start to reduce inrush current, foldback current limit, hiccup mode short- 28-pin 5mm 6mm MLF package circuit protection and thermal shutdown. An open-drain Power Good (PG) pin is provided. Applications All support documentation can be found on Micrels web site at: www.micrel.com. Distributed power systems Communications/networking infrastructure Set-top box, gateways, and routers Printers, scanners, graphic cards, and video cards Typical Application Efficiency (V = 12V) IN vs. Output Current 100 5.0V 95 3.3V 90 2.5V 1.8V 85 1.5V 1.2V 80 1.0V 75 0.9V 0.8V 70 65 60 55 50 0 1 2 345 67 8 OUTPUT CURRENT (A) Hyper Speed Control, SuperSwitcher II, and Any Capacitor are trademarks of Micrel, Inc. MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc. Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC26601 Ordering Information Junction Temperature Lead Part Number Voltage Switching Frequency Package Range Finish MIC26601YJL Adjustable 600kHz 40C to +125C 28-Pin 5mm 6mm MLF Pb-Free Pin Configuration 28-Pin 5mm 6mm MLF (YJL) Pin Description Pin Number Pin Name Pin Function 5V Internal Linear Regulator (Output): PVDD supply is the power MOSFET gate drive supply voltage 1 PVDD and created by internal LDO from V . When V < +5.5V, PVDD should be tied to PVIN pins. A 2.2F IN IN ceramic capacitor from the PVDD pin to PGND (Pin 2) must be place next to the IC. 3 NC No Connect. Switch Node (Output): Internal connection for the high-side MOSFET source and low-side MOSFET 4, 9, 10, SW drain. Due to the high-speed switching on this pin, the SW pin should be routed away from sensitive 11, 12 nodes. Power Ground. PGND is the ground path for the MIC26601 buck converter power stage. The PGND pins connect to the low-side N-Channel internal MOSFET gate drive supply ground, the sources of 2, 5, 6, 7, 8, PGND the MOSFETs, the negative terminals of input capacitors, and the negative terminals of output 21 capacitors. The loop for the power ground should be as small as possible and separate from the Signal ground (SGND) loop. High-Side N-internal MOSFET Drain Connection (Input): The PV operating voltage range is from IN 13,14,15, PVIN 4.5V to 28V. Input capacitors between the PVIN pins and the Power Ground (PGND) are required and 16,17,18,19 keep the connection short. Boost (Output): Bootstrapped voltage to the high-side N-channel MOSFET driver. A Schottky diode is connected between the PVDD pin and the BST pin. A boost capacitor of 0.1F is connected between 20 BST the BST pin and the SW pin. Adding a small resistor at the BST pin can slow down the turn-on time of high-side N-Channel MOSFETs. M9999-071311-A July 2011 2