MIC27600_11 Datasheet, PDF (2/28 Pages) Micrel Semiconductor – 36V, 7A Hyper Speed Control™ Synchronous DC-DC Buck Regulator

Micrel, Inc.
MIC27600
Ordering Information
Part Number Voltage Switching Frequency Junction Temperature Range
Package
MIC27600YJL Adjustable
300kHz
−40°C to +125°C
28-pin 5mm × 6mm MLF^®
Lead Finish
Pb-Free
Pin Configuration
28-Pin 5mm × 6mm MLF^® (YJL)
Pin Description
Pin
Number
13, 14, 15,
16, 17, 18,
19
Pin Name
PVIN
24
EN
25
FB
26
SGND
27
VDD
2, 5, 6, 7,
8, 21
PGND
22
CS
Pin Function
High-Side N-internal MOSFET Drain Connection (Input): The PV_IN operating voltage range is from
4.5V to 36V. Input capacitors between the PVIN pins and the power ground (PGND) are required and
keep the connection short.
Enable (Input): A logic level control of the output. The EN pin is CMOS-compatible. Logic high or
floating = enable, logic low = shutdown. In the off state, the V_DD supply current of the device is
reduced (typically 0.7mA). Do not pull the EN pin above the V_DD supply.
Feedback (Input): Input to the transconductance amplifier of the control loop. The FB pin is regulated
to 0.8V. A resistor divider connecting the feedback to the output is used to adjust the desired output
voltage.
Signal ground. SGND must be connected directly to the ground planes. Do not route the SGND pin to
the PGND Pad on the top layer, see PCB layout guidelines for details.
V_DD Bias (Input): Power to the internal reference and control sections of the MIC27600. The V_DD
operating voltage range is from 4.5V to 5.5V. A 2.2µF ceramic capacitor from the VDD pin to the
PGND pin must be placed next to the IC. V_DD must be powered up at the same time or after V_IN to
make the soft-start function correctly.
Power Ground. PGND is the ground path for the MIC27600 buck converter power stage. The PGND
pin connects to the sources of low-side N-Channel internal 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.
Current Sense (Input): High current output driver return. The CS pin connects directly to the switch
node. Due to the high-speed switching on this pin, the CS pin should be routed away from sensitive
nodes. CS pin also senses the current by monitoring the voltage across the low-side internal
MOSFET during OFF-time.
July 2011
2
M9999-070811