A8512 datasheet(5/16 Pages) ALLEGRO

5 / 16 page

LED Backlight Driver for LCD Monitors and Televisions

A8512

Allegro MicroSystems, Inc.

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

ELECTRICAL CHARACTERISTICS Valid at VIN = 12 V; TA = 25°C, RFSET = 52 kΩ, RISET = 12.4 kΩ, except indicates

specifications guaranteed over the full operating temperature range with TA = TJ, unless otherwise noted

Characteristics

Symbol

Test Conditions

Min.

Typ.1

Max.

Unit

Input Voltage Range

VIN

–

Internal Bias Voltage Range

VBIAS

4.75

–

5.5

Internal Gate Driver Voltage

VDRIVER

VIN ≥ 10 V

6.5

–

Undervoltage Lockout Threshold for VIN

VUVLO

VIN falling

5.7

6.5

6.8

Undervoltage Lockout Hysteresis for VIN

VUVLOHYS

–

0.55

–

Supply Current2

IVIN

Switching at no load

–

Shutdown, EN = VIL, TA = 25°C

–

0.1

μA

Standby, EN = VIH, PWM = VIL, soft start

completed

–23

Boost Controller

Switching Frequency

fSW

0.8

1.25

MHz

Minimum Switch Off-Time

toff(min)

Driver output

–

Minimum Switch On-Time

ton(min)

Driver output

–

Logic Input Levels (EN and PWM pins)

Input Voltage Level Low

VIL

–

0.4

Input Voltage Level High

VIH

1.5

–

Input Leakage Current2

IIN

EN = PWM = 5 V

–

100

–

μA

Error Amplifier

COMP Pin Source Current

IEA(src)

VCOMP = 1.5 V

–

160

–

μA

COMP Pin Sink Current

IEA(snk)

VCOMP = 1.5 V

–

μA

COMP Pin Pull-Down Resistance

RCOMPPD

¯F¯¯A¯¯¯U¯¯L¯¯T¯ = 0

–

1000

–

kΩ

Driver Section

Peak Source Current5

Ipk(src)

Measured at VDRIVER = 0 V

–

Peak Sink Current5

Ipk(snk)

Measured at VDRIVER = VREG7V

–2–

High Side Gate Drive On Resistance

RDS(on)H

Measured at VDRIVER = VREG7V / 2

–

Low Side Gate Drive On Resistance

RDS(on)L

Measured at VDRIVER = VREG7V / 2

–

Sense Overcurrent Threshold Voltage

VSEN

VSENSE1 – VSENSE2

110

LED Current Sinks

LEDx Pin Regulation Voltage

VLEDx

ILED = 80 mA

–

1.4

–

ISET to ILEDx Current Gain

AISET

ISET = 100 μA

–

640

–

A/A

ISET Pin Voltage

VISET

–

1.235

–

ISET Allowable Current Range2

ISET

–

190

μA

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