MIC26903ZA_14 Datasheet, PDF (2/29 Pages) Micrel Semiconductor – 28V, 9A Hyper Speed Control Synchronous DC/DC Buck Regulator

Micrel, Inc.
Ordering Information
Part Number
MIC26903-ZAYJL
Voltage
Adjustable
Switching
Frequency
600kHz
Pin Configuration
MIC26903-ZA
Package
28-Pin 5mm × 6mm QFN
Junction Temperature
Range
–40°C to +125°C
Lead
Finish
Pb-Free
28-Pin 5mm × 6mm QFN (JL)
(Top View)
Pin Description
Pin Number
1
2, 5, 6,
7, 8, 21
3
4, 9,
10, 11, 12
13,14,15,
16,17,18,19
20
Pin Name
PVDD
PGND
NC
SW
PVIN
BST
Pin Function
5V Internal Linear Regulator output: PVDD supply is the power MOSFET gate drive supply voltage
created by internal LDO from VIN. When VIN < +5.5V, PVDD should be tied to the PVIN pins. A 2.2µF
ceramic capacitor from the PVDD pin to PGND (pin 2) must be placed next to the IC.
Power Ground: PGND is the ground path for the buck converter power stage. The PGND pins connect
to the low-side N-Channel internal MOSFET gate drive supply ground, the sources of the MOSFETs,
the negative terminals of input capacitors, and the negative terminals of output capacitors. The loop
for the power ground should be as small as possible and separate from the signal ground (SGND)
loop.
No Connect.
Switch Node output: Internal connection for the high-side MOSFET source and low-side MOSFET
drain. Because of the high-speed switching on this pin, the SW pin should be routed away from
sensitive nodes.
High-Side N-Internal MOSFET Drain Connection input: The PVIN operating voltage range is from 4.5V
to 28V. Input capacitors between the PVIN pins and the power ground (PGND) are required and 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 0.1μF is connected between
the BST pin and the SW pin. Adding a small resistor at the BST pin can reduce the turn-on time of
high-side N-Channel MOSFETs.
July 22, 2014
2
Revision 1.1