MP1591 – 2A, 32V, 330KHz STEP-DOWN CONVERTER

MP1591 Rev. 2.1

www.MonolithicPower.com

3

12/5/2005

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TM

Parameter

Symbol Condition

Min

Typ

Max

Units

Thermal Shutdown

(4)

160

°C

REF Voltage

5.0

V

REF Load Regulation

(4)

100

mV

REF Line Regulation

(4)

30

mV

Notes:

4) These parameters are guaranteed by design, not production tested.

5) Equivalent output current = 1.5A ≥ 50% Duty Cycle

2.0A ≤ 50% Duty Cycle

Assumes ripple current = 30% of load current.

Slope compensation changes current limit.

PIN FUNCTIONS

Pin #

Name

Description

1

BS

High-Side Gate Drive Boost Input. BS supplies the drive for the high-side N-Channel MOSFET

switch. Connect a 10nF or greater capacitor from SW to BS to power the high-side switch.

2

IN

Power Input. IN supplies the power to the IC, as well as the step-down converter switches.

Drive IN with a 6.5V to 32V power source. Bypass IN to GND with a suitably large capacitor to

eliminate noise on the input to the IC. See Input Capacitor.

3

SW

Power Switching Output. SW is the switching node that supplies power to the output. Connect

the output LC filter from SW to the output load. Note that a capacitor is required from SW to BS

to power the high-side switch.

4

GND

Ground. For the MP1591DN, connect the Exposed Pad to pin 4.

5

FB

Feedback Input. FB senses the output voltage to regulate that voltage. Drive FB with a resistive

voltage divider from the output voltage. The feedback threshold is 1.230V. See Setting the

Output Voltage

.

6

COMP Compensation Node. COMP is used to compensate the regulation control loop. Connect a

series RC network from COMP to GND to compensate the regulation control loop. In some

cases, an additional capacitor from COMP to GND is required. See Compensation.

7

EN

Enable/UVLO. A voltage greater than 2.8V enables operation. For complete low current

shutdown the EN pin voltage needs to be less than 800mV.

8

REF

Reference Output. REF is the 5V reference voltage output. It can supply up to 1mA to external

circuitry. If used, bypass REF to GND with 10nF or greater capacitor. Leave REF unconnected

if not used.