A4480KLJTR-T - ALLEGRO MICROSYSTEMS

Not to scale

A4480

A4480-DS, Rev. 2

MCO-000191

FEATURES AND BENEFITS

• Automotive AEC-Q100 qualified

• Wide operating range of 3.5 to 28 V, with 40 V load

dump rating

• Linear regulator output with foldback short-circuit and

short-to-battery protection

• Boost function to maintain output when input is low

• Power OK (POK) flag

• High-voltage logic-level enable input (ENB) for

microprocessor or ignition control

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

Wide Input 5 V, 50 mA, Automotive Regulator

with Output Short-to-Battery Protection and Power OK

Figure 1: Typical Application Circuit

PACKAGE

8-pin SOIC with exposed thermal pad (suffix LJ)

DESCRIPTION

The A4480 is a wide input regulator with complete control,

diagnostics, and protection features that address many

requirements of automotive applications. It includes a boost

function to allow operation with input voltages from 3.5 to

28 V, while maintaining a 5 V output voltage. The A4480 is

able to supply up to 50 mA of load current.

An enable pin (ENB) allows control of the regulator output.

This pin is rated to operate at up to 40 V, so it can be connected

directly to a car battery.

Diagnostic output from the A4480 includes an open-drain

Power OK (POK) output to alert the microprocessor that a

fault has occurred.

Protection features include input undervoltage lockout (UVLO),

foldback overcurrent protection, output under/overvoltage

protections (UV/OVP), and thermal shutdown (TSD). In

addition, the output is protected from a short-to-battery event.

The A4480 device is available in an 8-pin eSOIC package with

exposed pad for enhanced thermal dissipation. It is lead (PB)

free, with 100% matte tin leadframe plating.

IO Voltage

or VOUT

A4480

GND

VIN

VOUT

Enable from

µP or VIN ENB

POK

VOUT

VREG

CP2

CP1

VIN

July 5, 2018

APPLICATIONS

• Microcontroller power

• Transceivers (CAN, LIN, etc.) power supplies

• Sensors

Wide Input 5 V, 50 mA, Automotive Regulator

with Output Short-to-Battery Protection and Power OK

A4480

Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

ABSOLUTE MAXIMUM RATINGS*

Characteristic Symbol Notes Rating Unit

VIN, ENB, CP1 VIN, VENB, VCP1 −0.3 to 40 V

VCP2, VREG, VPOK VCP2, VREG, VPOK −0.3 to 20 V

VOUT VOUT Independent of VIN −1 to 40 V

Junction Temperature Range TJ−40 to 165 °C

Storage Temperature Range Tstg −40 to 150 °C

*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 Char-

acteristics table is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

SELECTION GUIDE

Part Number Temperature Range (°C) Package Leadframe Packing*

A4480KLJTR-T –40 to 150 8-pin eSOIC with exposed thermal pad Matte Tin 3000 pieces per 7-in. reel

*Contact Allegro for additional packing options.

THERMAL CHARACTERISTICS*: May require derating at maximum conditions; see application section for optimization

Characteristic Symbol Test Conditions* Value Unit

Package Thermal Resistance

(Junction to Ambient) RθJA eSOIC-8 with thermal pad (LJ) package on 4-layer PCB based on JEDEC standard 35 °C/W

*Additional thermal information available on the Allegro website.

Wide Input 5 V, 50 mA, Automotive Regulator

with Output Short-to-Battery Protection and Power OK

A4480

Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

Figure 2: Functional Block Diagram

VOUT

FOLDBACK

5 V

LDO

Short to VBAT

Protection

VOUT UV/OV

OCP

TSD

LDO2 Vcc

Charge Pump

GND

CP1

CP2

VREG

POK

VIN

ENB

Pinout Diagram

PAD

VIN

CP1

CP2

POK

VREG

VOUT

GND

ENB

Terminal List Table

Number Name Function

1 VIN Connection for input voltage. Connect a 2.2 µF capacitor from this pin

to GND. Keep capacitor close to A4480.

2 CP1

Internal charge pump flying capacitor connection, connect a 0.47 µF

ceramic capacitor from this pin to the CP2 pin. Keep capacitor close

to A4480.

3CP2 Internal charge pump flying capacitor connection, use a 0.47 µF

capacitor to CP1.

4 POK Open-drain active-high Power OK signal. Use a 100 kΩ pull-up

resistor to system IO rail or VOUT.

5 ENB Regulator active high enable input. Can be connected to VIN or logic

level signal.

6GND Ground pin.

7VOUT Regulated output pin. It is recommended to use a 4.7 µF ceramic

capacitor from this pin to GND. Keep capacitor close to A4480.

8 VREG

Charge pump output which is input to internal linear regulator.

Connect a 2.2 µF ceramic capacitor from this pin to GND. Keep

capacitor close to A4480.

Wide Input 5 V, 50 mA, Automotive Regulator

with Output Short-to-Battery Protection and Power OK

A4480

Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

Characteristics Symbol Test Conditions Min. Typ. Max. Units

INPUT VOLTAGE

Operating Input Voltage VIN ENB high and after VIN > 6.0 V 3.5 13.5 28 V

VIN UVLO Start Voltage VIN(START) VIN rising, ENB high 3.1 –3.45 V

VIN UVLO Stop Voltage VIN(STOP) VIN falling, ENB high 2.6 – 2.9 V

VIN UVLO Hysteresis VIN(HYS) VIN(START) – VIN(STOP) –0.6 – V

INPUT CURRENT

Input Quiescent Current

[1] IQVIN = 13.5 V, ENB high – 4 – mA

Input Sleep Supply Current

[1] IQ(SLEEP) VIN = 13.5 V, ENB low – 1 10 µA

CHARGE PUMP

Output Voltage VREG

ENB high, 5 mA ≤ IOUT ≤ 50 mA, VIN = 3.95 V 5.25 – 7V

ENB high, 5 mA ≤ IOUT ≤ 33 mA, VIN = 3.5 V 5.25 – 7V

Switching Frequency fSW –325 –kHz

Doubler to Pass Through Switchover VDOUBLER(H) VIN rising 7.8 –8.65 V

Pass Through to Step Down Switchover VSTEPDOWN(H) VIN rising 11.5 – 12.45 V

Step Down to Pass Through Switchover VSTEPDOWN(L) VIN falling 10.5 – 11.7 V

Pass Through to Doubler Switchover VDOUBLER(L) VIN falling 6.9 –7.5 V

5 V LINEAR REGULATOR

Accuracy and Load Regulation VOUT

5 mA ≤ IOUT ≤ 50 mA, 3.95 V ≤ VIN ≤ 28 V 4.9 5.0 5.1 V

5 mA ≤ IOUT ≤ 33 mA, 3.5 V ≤ VIN < 3.95 V 4.9 5.0 5.1 V

Output Capacitance Range

[2] COUT 3– 10 µF

Startup Time

[2] tSTART COUT ≤ 4.7 µF, Load = 125 Ω ±5% (50 mA) 1.4 2.2 3.0 ms

ENB Threshold VENB(H) VENB rising – – 2.0 V

VENB(L) VENB falling 0.8 – – V

ENB Resistance RENB – 100 – kΩ

ENB Filter/Deglitch Time td(EN,FILT) 10 15 20 µs

ELECTRICAL CHARACTERISTICS [1]: Valid at 3.5 V ≤ VIN ≤ 28 V, −40°C ≤ TJ ≤ 150°C, unless otherwise specied

Continued on next page...

Wide Input 5 V, 50 mA, Automotive Regulator

with Output Short-to-Battery Protection and Power OK

A4480

Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

OVERCURRENT PROTECTION (OCP)

Current Limit

[1] ILIM VOUT = 5 V −60 −100 –140 mA

Foldback Current

[1] IFBK VOUT = 0 V −15 −30 −45 mA

THERMAL PROTECTION (TSD)

Thermal Shutdown Threshold

[2] TTSD TJ rising 165 − − °C

Thermal Shutdown Hysteresis

[2] THYS −15 −°C

VOUT OV/UV PROTECTIONS

VOUT OV Thresholds VOV(H) VOUT rising, VIN = 13.5 V 5.15 5.33 5.50 V

VOV(L) VOUT falling, VIN = 13.5 V –5.30 – V

VOUT OV Hysteresis VOV(HYS) VOV(H) – VOV(L), VIN = 13.5 V 15 – 50 mV

VOUT UV Thresholds VUV(H) VOUT rising, VIN = 13.5 V –4.71 – V

VUV(L) VOUT falling, VIN = 13.5 V 4.50 4.68 4.85 V

VOUT UV Hysteresis VUV(HYS) VUV(H) – VUV(L), VIN = 13.5 V 15 – 50 mV

VOUT Output Disconnect Threshold VDISC VOUT rising, VIN = 13.5 V –7.2 – V

POK OUTPUTS

POK Output Low Voltage VPOK(L) ENB high, VIN ≥ 3.5 V, IPOK = 1 mA – 150 400 mV

POK Leakage Current

[1] IPOK(LKG) VPOK = 3.3 V – – 35 µA

OV and UV Filter/Deglitch Times

[2] td(FILT) Applies to undervoltage of the VOUT voltages 10 15 20 µs

[1] For input and output current specications, negative current is dened as coming out of the node or pin (sourcing), positive current is dened as going into the node or pin

(sinking).

[2] Ensured by design and characterization, not production tested.

ELECTRICAL CHARACTERISTICS (continued) [1]: Valid at 3.5 V ≤ VIN ≤ 28 V, −40°C ≤ TJ ≤ 150°C,

unless otherwise specied

Wide Input 5 V, 50 mA, Automotive Regulator

with Output Short-to-Battery Protection and Power OK

A4480

Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

Figure 3: Output Current Derating versus Input Voltage

Figure 4: Timing Diagram (not to scale)

UV(H)

td(filt)

UV(L)

ENB(H)

POK

VOUT

ENB

VIN

td(EN,FILT)

IN(STOP)

IN(START)

ENB(L)

OV(H)

OV(L)

DISC

td(filt)

Wide Input 5 V, 50 mA, Automotive Regulator

with Output Short-to-Battery Protection and Power OK

A4480

Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

Figure 5: Typical Application Schematic

VIN

GND

VOUT

GND

POK

SW1

A4480

CP1

VREG 8

ENB 5

VOUT 7

POK

GND 6

CP2

VIN

PAD

2.2 µF

0.47 µF

2.2 µF

4.7 µF

100 kΩ

BZX 84-C24

Optional*

BAS 16

ENB

* Diodes D1 and D2 are only required if A4480 must be enabled when V

is greater than 28 V.

If A4480 is already enabled before VIN is greater than 28 V or if A4480 is off then operation to 40 V

is possible without D1 and D2 diodes.

Wide Input 5 V, 50 mA, Automotive Regulator

with Output Short-to-Battery Protection and Power OK

A4480

Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

PERFORMANCE DATA

4.90

4.92

4.94

4.96

4.98

5.00

5.02

5.04

5.06

5.08

5.10

3813 18 23 28

Output Voltage (V)

Input Voltage (V)

4.98

4.99

5.01

5.02

5.03

5.04

5.05

5.06

0.00 0.01 0.02 0.03 0.04 0.05

Output Voltage (V)

Output Current (A)

Vin = 3.5V

Vin = 13V

Vin = 28V

10%

20%

30%

40%

50%

60%

70%

80%

0.00 0.01 0.02 0.03 0.04 0.05

Efficicency

Output Current (A)

Vin = 3.5V

Vin = 13V

0 5 10 15 20 25 30

Temperature Rise (°C)

Input Voltage (V)

Line Regulation at 50 mA Load Regulation

Typical E󰀩ciency Estimated Temperature Rise

Wide Input 5 V, 50 mA, Automotive Regulator

with Output Short-to-Battery Protection and Power OK

A4480

Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

The A4480 contains a switching charge pump circuit, so care

must be taken when placing this part on the system PCB. The four

decoupling capacitors (C1, C2, C3, and C4) must be placed as

close to the A4480 as possible. Figure 6 below shows the recom-

mend layout. The input capacitor C1 is placed next to pin 1 of

the A4480 (U1). It connects directly to the pin 6 using copper on

the top side of the PCB. The charge pump flying capacitor (C2)

connects directly to pins 2 and 3 of A4480. The VREG capacitor

connects to pins 8 and 6; top-side copper should only be used for

this connection. The output capacitor (C4) connects to pins 7 and 8.

PCB LAYOUT GUIDELINES

Figure 6: Typical Layout of the A4480

The vias under the A4480 are recommended for improved ther-

mal performance. The ground copper plane should be a large as

possible to reduce the junction to ambient thermal impedance of

the A4480.

Wide Input 5 V, 50 mA, Automotive Regulator

with Output Short-to-Battery Protection and Power OK

A4480

Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

3.30

Reference land pattern layout (reference IPC7351

SOIC127P600X175-9AM); all pads a minimum of 0.20 mm from all

adjacent pads; adjust as necessary to meet application process

requirements and PCB layout tolerances; when mounting on a multilayer

PCB, thermal vias at the exposed thermal pad land can improve thermal

dissipation (reference EIA/JEDEC Standard JESD51-5)

PCB Layout Reference View

1.27

5.602.41

1.75

0.65

2.41 NOM

3.30 NOM

SEATING

PLANE

1.27 BSC

GAUGE PLANE

SEATING PLANE

ATerminal #1 mark area

SEATING

PLANE

C0.10

0.25 BSC

1.04 REF

1.70 MAX

For Reference Only; not for tooling use (reference MS-012BA)

Dimensions in millimeters

Dimensions exclusive of mold flash, gate burrs, and dambar protrusions

Exact case and lead configuration at supplier discretion within limits shown

4.90 ±0.10

3.90 ±0.10 6.00 ±0.20

0.51

0.31 0.15

0.00

0.25

0.17

1.27

0.40

8°

0°

Exposed thermal pad (bottom surface); dimensions may vary with device

Branded Face

Figure 7: Package LJ, 8-Pin eSOIC

PACKAGE OUTLINE DRAWING

Wide Input 5 V, 50 mA, Automotive Regulator

with Output Short-to-Battery Protection and Power OK

A4480

Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

For the latest version of this document, visit our website:

www.allegromicro.com

Allegro MicroSystems, LLC reserves the right to make, from time to time, such departures from the detail specifications as may be required to

permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that

the information being relied upon is current.

Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of

Allegro’s product can reasonably be expected to cause bodily harm.

The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, LLC assumes no responsibility for its

use; nor for any infringement of patents or other rights of third parties which may result from its use.

Copies of this document are considered uncontrolled documents.

Revision History

Number Date Description

–June 1, 2017 Initial release

1July 10, 2017 Updated Charge Pump Output Voltage test conditions (page 4), Accuracy and Load Regulation test

conditions (page 4), and Figure 3 (page 6).

2 July 5, 2018 Minor editorial updates