MIC26950_11 Datasheet, PDF (2/28 Pages) Micrel Semiconductor – 12A Hyper Speed ControlTM Synchronous DC-DC Buck Regulator

Micrel, Inc.
Ordering Information
Part Number
MIC26950YJL
Voltage
Adjustable
Switching Frequency
Junction Temperature
Range
300kHz
–40°C to +125°C
Package
28-pin 5mm × 6mm MLF^®
Pin Configuration
MIC26950
Lead Finish
Pb-Free
28-Pin 5mm X 6mm MLF^® (YJL)
Pin Description
Pin
Number
Pin Name
13,14,15,
16,17,18,
19
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 26V. Input capacitors between PV_IN and the power ground (PGND) are required.
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, supply current of the device is greatly reduced
(typically 0.8mA).
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.
V_DD Bias (Input): Power to the internal reference and control sections of the MIC26950. The V_DD
operating voltage range is from 4.5V to 5.5V. A 2.2µF ceramic capacitor from the VDD pin-to-PGND is
recommended for clean operation.
Power Ground. PGND is the ground path for the MIC26950 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
M9999-070111-C