Adjustable Frequency Buck or Buck-Boost Pre-Regulator with a

Synchronous Buck, 3 LDOs, Pulse-Width Window Watchdog, NPOR, and POK5V

A4411

9

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Characteristic

Symbol

Test Conditions

Min.

Typ.

Max.

Unit

OUTPUT VOLTAGE SPECIFICATIONS

Buck Output Voltage – Regulating

5.25

5.35

5.45

V

PULSE-WIDTH MODULATION (PWM)

PWM Ramp Offset

–

400

–

mV

–

0.9

–

V/ns

–

0.3

–

V/ns

–

1.5

–

V/ns

Buck Minimum On-Time

–

100

150

ns

Buck Maximum Duty Cycle

–

100

–

%

Boost Minimum Off-Time

100

130

230

ns

Boost Duty Cycle

–

20

–

%

–

58

68

%

COMP1 to LX1 Current Gain

–

4.5

–

A/V

1.04

1.48

1.92

A/µs

0.22

0.33

0.44

A/µs

INTERNAL MOSFET

MOSFET On-Resistance

–

50

65

mΩ

–

75

90

mΩ

–

150

180

mΩ

MOSFET Leakage

–

–

10

µA

–

50

150

µA

ERROR AMPLIFIER

Open-Loop Voltage Gain

–

60

–

dB

Transconductance

550

750

950

µA/V

275

375

475

µA/V

Output Current

–

±75

–

µA

Maximum Output Voltage

1.3

1.7

2.1

V

Minimum Output Voltage

–

–

300

mV

COMP1 Pull-Down Resistance

HICCUP1 = 1 or FAULT1 = 1 or

–

1

–

kΩ

1

Negative current is defined as coming out of the node or pin (sourcing), positive current is defined as going into the node or pin (sinking).

2

Ensured by design and characterization, not production tested.

3

Specifications at 25°C or 85°C are guaranteed by design and characterization, not production tested.

unless otherwise specified.

Continued on next page...