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

Synchronous Buck, 3 Internal LDOs, Watchdog Timer, NPOR, and FF0/FF1

A4408

2

Allegro MicroSystems, LLC

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

SELECTION GUIDE

Part Number

Package

Lead Frame

A4408KLVTR-T

38-pin eTSSOP with thermal pad

4000 pieces per 7-inch reel

100% matte tin

1

Contact Allegro for additional packing options.

• FF0, FF1 Fault Flags—last microcontroller RESET indicators

• Slew rate control pin helps reduce EMI/EMC

• Frequency dithering helps reduce EMI/EMC

• Overvoltage and undervoltage protection for all four CPU

supply rails

• Pin-to-pin and pin-to-ground tolerant at every pin

• Thermal shutdown protection

• −40°C to 150°C junction temperature range

the V5P output is protected from a short-to-battery event. Both

switching regulators include pulse-by-pulse current limit, hiccup

mode short-circuit protection, LX short-circuit protection, missing

asynchronous diode protection (VREG), and thermal shutdown.

The A4408 is supplied in a low profile (1.2 mm maximum height)

38-lead eTSSOP package (suffix “LV”) with exposed thermal pad.

FEATURES AND BENEFITS (continued)

DESCRIPTION (continued)

Characteristic

Symbol

Notes

Rating

Unit

VIN

−0.3 to 40

V

ENBAT1, ENBAT2

−13 to 40

V

−0.3 to 8

V

±75

mA

LX1, SLEW

V

t < 250 ns

−1.5

V

t < 50 ns

V

VCP, CP1, CP2

−0.3 to 50

V

V5P

−1 to 40

V

All other pins

−0.3 to 7

V

Junction Temperature

−40 to 150

°C

Storage Temperature Range

−40 to 150

°C

2

Stresses beyond those listed in this table may cause permanent damage to the device. The absolute maximum ratings are stress ratings only, and functional operation of

the device at these or any other conditions beyond those indicated in the Electrical Characteristics table is not implied. Exposure to absolute-maximum-rated conditions

for extended periods may affect device reliability

3

The higher ENBAT1 and ENBAT2 ratings (–13 V and 40 V) are measured at node “A” in the following circuit configuration:

+

-

Node “A”

≥450

VEN

ENBATx

GND

A4408

THERMAL CHARACTERISTICS: May require derating at maximum conditions; see application information

Characteristic

Symbol

Value

Unit

Junction to Pad Thermal Resistance

eTSSOP-38 (LV) Package

30

°C/W

4

Additional thermal information available on the Allegro website.

SPECIFICATIONS