MIC2101_13 Datasheet, PDF (3/36 Pages) Micrel Semiconductor – 38V, Synchronous Buck Controllers Featuring Adaptive On-Time Control

Micrel, Inc.
MIC2101/02
Pin Configuration (Continued)
Pin Number
7
8
9, 11
10
12
13
14
15
16
EP
Pin Name
DH
SW
NC
BST
AGND
FB
PG
EN
VIN
ePad
Pin Function
High-Side Drive Output. High-current driver output for external high-side MOSFET of a buck
converter. The DH driving voltage is floating on the switch node voltage (VSW). Adding a small
resistor between DH pin and the gate of the high-side N-channel MOSFET can slow down the
turn-on and turn-off speed of the MOSFET.
Switch Node and Current-Sense input. High current output driver return. The SW pin connects
directly to the switch node. Due to the high-speed switching on this pin, the SW pin should be
routed away from sensitive nodes. The SW pin also senses the current by monitoring the voltage
across the low-side MOSFET during OFF time. In order to sense the current accurately, connect
the low-side MOSFET drain to the SW pin using a Kelvin connection.
No Connection.
Voltage supply input for the high-side N-channel MOSFET driver, which can be powered by a
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ceramic capacitor. Adding a small resistor at BST pin can slow down the turn-on speed of the
high-side MOSFET.
Signal ground for VDD and the control circuitry, which is connected to thermal pad electronically.
The signal ground return path should be separate from the power ground (PGND) return path.
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 set the
desired output voltage.
Power Good Output. Open drain output, an external pull-up resistor to VDD or external power
rails is required.
Enable Input. A logic signal to enable or disable the buck converter operation. The EN pin is
CMOS compatible. Logic high enables the device, logic low shutdowns the regulator. In the
disable mode, the VDD supply current for the device is minimized to 0.7mA typically. Don not pull
EN pin to VDD/PVDD.
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from VIN to AGND is required for decoupling.
Exposed Pad. Connect the EPAD to PGND plain on the PCB to improve the thermal
performance.
November 13, 2013
3
Revision 2.0