MIC2198

Micrel

MIC2198

2

November 2004

Pin Configuration

1

2

3

4

COMP

EN/UVLO

FB

CSH

HSD

VSW

BST

GND

VOUT

VIN

5

6

12

11

10

9

8

7

LSD

VDD

4×

×

×

×

×4 MLF-12L (ML)

Ordering Information

Part Number

Voltage

Temperature Range

Package

MIC2198BML

Adj

–40°C to +125°C

12-lead 4×4 MLF™

Pin Description

Pin Number

Pin Name

Pin Function

1

COMP

Compensation (Output): Internal error amplifier output. Connect to capacitor

or series RC network to compensate the regulator control loop.

2

EN/UVLO

Enable/Undervoltage Lockout (Input): Low-level signal powers down the

controller. Input below the 2.5V threshold disables switching and functions

as an accurate undervoltage lockout (UVLO). Input below the threshold

forces complete micropower (<0.1µA) shutdown.

3

FB

Feedback (Input): Regulates FB pin to 0.8V. See

“Applications Information”

for resistor divider calculations.

4

CSH

Current-Sense High (Input): Current limit comparator non-inverting input. A

built-in offset of 75mV between CSH and V

current-sense resistor set the current limit threshold level. This is also the

non-inverting input to the current sense amplifier.

5

VOUT

Current-Sense Low (Input): Output voltage feedback input and inverting

input for the current limit comparator and the current sense amplifier.

6

VIN

Unregulated Input (Input): +4.5V to +32V supply input.

7

VDD

5V Internal Linear-Regulator (Output): V

drive supply voltage and internal supply bus for the IC. Bypass to GND with

4.7µF.

8

LSD

Low-Side Drive (Output): High-current driver output for low-side N-Channel

MOSFET. Voltage swing is between ground and V

9

GND

Ground (Return).

10

BST

Boost (Input): Provides drive voltage for the high-side MOSFET driver. The

drive voltage is higher than the input voltage by V

11

VSW

Switch (Return): High-side MOSFET driver return.

12

HSD

High-Side Drive (Output): High-current driver output for high-side MOSFET.

This node voltage swing is between ground and V