A8511 Ver la hoja de datos (PDF) - Allegro MicroSystems

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A8511

2 MHz, 4 Channel × 150 mA WLED/RGB Driver with Output Disconnect

Allegro MicroSystems 

A8511

2 MHz, 4 Channel×150 mA WLED/RGB Driver

with Output Disconnect

Pin-out Diagram

BIAS 1

DGND 2

DIM 3

SW 4

SW 5

SW 6

OVP 7

CAP 8

AGND 9

ISET 10

VTI 11

VTO 12

LED1 13

LED2 14

28 EN

27 SEL2

26 SEL1

25 PGND

24 PGND

23 PGND

PAD

22 NC

21 VIN

20 COMP

19 FSET

18 OUT

17 LED4

16 LED3

15 LGND

Terminal List Table

Number Name

Function

1

BIAS Output of internal 6 V bias supply. Decouple with a 0.1 μF ceramic capacitor to DGND.

2

DGND Digital signal ground. Connect AGND, DGND, LGND, PGND, and PAD using star ground connection.

3

4, 5, 6

DIM Sets ILED by adjusting the ISET to ILEDx current gain, AISET . When DIM = VIL , AISET = 960 and when DIM=VIH , AISET = 240.

SW DMOS switch drain node. Tie these three pins together on the PCB.

7

OVP

To enable overvoltage protection, connect this pin through a resistor to the CAP pin. The default OVP level, with 0 Ω resistor,

is 19.5 V. External resistor can set OVP up to 38 V.

8

CAP Input connection for output disconnect switch.

9

AGND Analog signal ground. Connect AGND, DGND, LGND, PGND, and PAD using star ground connection.

10

ISET Sets the 100% current level through LED strings. Set by value of RISET connected between ISET and AGND.

ISET voltage override. Sets the ISET voltage when VTI < 1.23 V. Tie directly to VTO pin to disable this feature. This pin can

11

VTI be used for LED current thermal derating or external analog LED current control. See the Typical Application Circuits section

for additional information.

12

VTO

2.46 V output voltage. Use this voltage to bias an external NTC resistor or as a DAC reference. This pin can be used as a

logic high signal for the SEL and DIM pins.

13,14,16,17 LEDX LED current sinks.

15

LGND Power ground for LED current sinks. Connect AGND, DGND, LGND, PGND, and PAD using star ground connection.

18

OUT Output connection for output disconnect switch. Connect LED common connection to this pin.

19

FSET Connect RFSET between FSET and AGND to set boost switching frequency.

20

COMP Sets boost loop compensation. Connect external compensation capacitor between COMP and AGND for boost converter stability.

21

VIN Input supply for the device. Decouple with a 0.1 μF ceramic capacitor.

22

NC Not connected internally. It is recommended to connect this pin to external ground.

23, 24, 25 PGND Power ground. Connect AGND, DGND, LGND, PGND, and PAD using star ground connection.

26

SEL1

SEL1 and SEL2 together select which LED strings are enabled. See Functional Description section.

27

SEL2

28

EN Enable and PWM LED current control. Apply logic-level PWM for PWM-controlled dimming mode.

–

PAD

Exposed thermal pad. Connect AGND, DGND, LGND, PGND, and PAD using star ground connection. Connect to PCB

copper layer for enhanced heat dissipation.

8511-DS

Allegro MicroSystems, Inc.

4

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

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