Micrel, Inc.

MIC2101/02

November 13, 2013

3

Revision 2.0

Pin Configuration (Continued)

Pin Number

Pin Name

Pin Function

7DH

High-Side Drive Output. High-current driver output for external high-side MOSFET of a buck

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.

8SW

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.

9, 11

NC

No Connection.

10

BST

Voltage supply input for the high-side N-channel MOSFET driver, which can be powered by a

ceramic capacitor. Adding a small resistor at BST pin can slow down the turn-on speed of the

high-side MOSFET.

12

AGND

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.

13

FB

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.

14

PG

Power Good Output. Open drain output, an external pull-up resistor to VDD or external power

rails is required.

15

EN

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.

16

VIN

from VIN to AGND is required for decoupling.

EP

ePad

Exposed Pad. Connect the EPAD to PGND plain on the PCB to improve the thermal

performance.