SC667 datasheet, PDF - EEWORLD Datasheet

SC667

7 LED Light Management Unit

POWER MANAGEMENT

Features



Automatic Dropout Prevention, Ambient Light

Sense Input, PWM Dimming, and 4 LDOs

Description

The SC667 is a highly integrated light management unit

that provides programmable current for up to seven LED

current sinks. Four LED banks are provided to allow set-

tings for various LED zones or indicators. Four low-noise

LDOs with programmable outputs ranging from 1.2V to 3.3V

and 200mA maximum output current are also included.

ADP limits the maximum LED current to a level that ensures

the LEDs maintain matched currents when the supply

voltage approaches dropout. This feature produces accept-

able light output at low supply voltage levels without

requiring a boost converter or charge pump.

Two interfaces are provided for design flexibility. The I

2

C

interface controls the LED on/off functions, assigns the

LEDs to backlight banks, programs the LED currents, pro-

grams the lighting effects, enables the LDOs, and sets the

LDO output voltages. The PWM interface reduces the

current setting for LED bank #1 by a factor equal to the duty

cycle of the applied PWM signal. A filter at the PWM input

converts the pulsed signal to a DC current level, resulting in

less switching noise compared to pulsed current methods.

The ADI input translates the voltage from an external ALS

(Ambient Light Sensor) into a digitized code using a sigma-

delta ADC. This block includes level detection to adjust the

current setting of bank #1 with two different programmable

levels based on the ambient light level. An interrupt output

transitions low to notify the host processor that a level

adjustment has been made.

SC667

V

IN

BL1

BL2

GND

SDA

SCL

PWM

EN

ADI

BYP

C

BYP

BL3

BL4

BL5

BL6

BL7

IRQ

LDO1

LDO2

LDO3

LDO4

C

1

C

2

C

3

C

4

V

DD

R

1

Flag for ALS

LDO1

LDO2

LDO3

LDO4

Seven LED backlight sinks with 32 current settings

from 0mA to 25mA

Up to four LED backlight banks

Lighting effects — fade-in/fade-out, breathe, blink,

auto-dim full, and auto-dim partial functions

ADP (Automatic Dropout Prevention) for backlights

ALS (Ambient Light Sense) option sets the backlight

brightness according to ambient lighting conditions

I

2

C Bus fast mode and standard mode

IRQ (Interrupt request) — open-drain output indi-

cates a change of state for the ALS

Backlight current accuracy — ±1.5% typical

Backlight current matching — ±0.5% typical

Four programmable 200mA low-noise LDO regulators

PWM interface (200Hz to 50kHz) with internal digital

low-pass filter

Automatic sleep mode with all LEDs off

Shutdown current — 0.1µA typical

Ultra-thin package — 3 x 3 x 0.6 (mm)

Lead-free and halogen-free

WEEE and RoHS compliant

Applications



Cellular phones, smart phones, and PDAs

LCD modules

Portable media players and digital cameras

Personal navigation devices

Display/keypad backlighting and LED indicators

Typical Application Circuit

2.9 to 5.5V

R

SDA

I C Data

I C Clock

Backlight PWM

Device Enable

V

LDO4

2

V

IN

C

IN

R

SCL

IN

Ambient Light Sensor

May 21, 2010

1

SC667

Pin Configuration

LDO2

LDO3

LDO4

Ordering Information

Device

BYP

EN

Package

MLPQ-UT-20 3×3

Evaluation Board

SC667ULTRT

(1)(2)

SC667EVB

20

19

18

17

16

LDO1

VIN

GND

PWM

BL7

1

TOP VIEW

2

3

4

5

T

15

14

13

12

11

IRQ

SDA

SCL

ADI

BL1

Notes:

(1) Available in tape and reel only. A reel contains 3,000 devices.

(2) Lead-free package only. Device is WEEE and RoHS compliant and

halogen-free.

6

7

8

9

10

BL6

BL5

BL4

BL3

MLPQ-UT-20; 3x3, 20 LEAD

θ

JA

= 35°C/W

Marking Information

667

yyww

xxxx

yyww = Date Code

xxxx = Semtech Lot Number

BL2

2

SC667

Absolute Maximum Ratings

Pin Voltage — IN (V) . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.0

Pin Voltage — All Other Pins (V) . . . . . . . . . -0.3 to (V

IN

+ 0.3)

LDOn

(1)

Short Circuit Duration . . . . . . . . . . . . . . .Continuous

ESD Protection Level

(2)

(kV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5

Recommended Operating Conditions

Ambient Temperature Range (°C) . . . . . . . . . .-40

≤

T

A

≤

+85

Input Voltage (V) . . . . . . . . . . . . . . . . . . . . . . . . .2.9

≤

V

IN

≤

5.5

Backlight Sink Voltage (V) . . . . . . . . . . . . . . . .0.05

≤

V

BLn

≤

4.2

Thermal Information

Thermal Resistance, Junction to Ambient

(3)

(°C/W) . . . . 35

Storage Temperature Range (°C) . . . . . . . . . . . . -65 to +150

Peak IR Reflow Temperature (10s to 30s) (°C) . . . . . . . +260

Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters

specified in the Electrical Characteristics section is not recommended.

NOTES:

(1) Subscripting for all LDOs (LDOn), n = 1, 2, 3, 4.

(2) Tested according to JEDEC standard JESD22-A114-B.

(3) Calculated from package in still air, mounted to 3 x 4.5 (in), 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards.

Electrical Characteristics

Parameter

Supply Specifications

Input Supply Voltage

Shutdown Current

Unless otherwise noted, T

A

= +25°C for Typ, -40ºC to +85°C for Min and Max, T

J(MAX)

= 125ºC, V

IN

= 3.7V, C

IN

= C

LDO1

= C

LDO2

= C

LDO3

= C

LDO4

= 1.0µF,

C

BYP

= 22nF, (ESR = 0.03Ω)

(1)

Symbol

Conditions

Min

Typ

Max

Units

V

IN

I

Q(OFF)

Shutdown, V

IN

= 4.2V

Sleep (all LDOs off ), EN = V

IN(2)

2.9

0.1

90

300

1.4

5.5

2.0

135

V

µA

450

mA

Total Quiescent Current

I

Q

Sleep (all LDOs on), EN = V

IN

7 LEDs on

(2)

LED Sink Electrical Specifications

Maximum Total Backlight Current

Backlight Current Setting Range

Backlight Current Accuracy

Backlight Current Matching

(4)

Dropout Voltage

(5)

Current Sink Off-State Leakage Current

I

OUT(MAX)

I

BL

I

BL_ACC

I

BL-BL

V

DO

I

BL/FL(OFF)

Sum of all active LED currents, V

IN

above dropout level

Nominal setting for BL1 – BL7

I

BLn (3)

= 12mA

I

BLn (3)

= 12mA

One bank of 6 backlights set equal to 20mA

V

IN

= V

BLn(3)

= 4.2V

-3.5

0

±1.5

±0.5

59

0.1

1

+3.5

175

25

mA

%

mV

µA

3

SC667

Electrical Characteristics (continued)

Parameter

LDO Electrical Specifications

LDO1, LDO3, and LDO4

Voltage Setting Range

LDO2 Voltage Setting Range

V

LDOm(6)

V

LDO2

∆V

LDO

V

Dm (6)

V

D2

Current Limit

I

LIM

DV

LINE

I

LDOm (6)

= 1mA, V

IN

= 2.9V to 4.2V, V

LDOm

= 2.8V

I

LDO2

= 1mA, V

IN

= 2.9V to 4.2V, V

LDO2

= 1.8V

V

LDOm (6)

= 3.3V, I

LDOm

= 1mA to 100mA

V

LDO2

= 1.8V, I

LDO2

= 1mA to 100mA

1.5V < V

LDOm

< 3.0V, f < 10kHz, C

BYP

= 22nF,

I

LDOm

= 50mA, with 0.5V

P-P

supply ripple

1.2V < V

LDO2

< 1.8V, f < 10kHz, C

BYP

= 22nF,

I

LDO2

= 50mA, with 0.5V

P-P

supply ripple

10Hz < f < 100kHz, C

BYP

= 22nF,

C

LDOm

= 1µF, I

LDOm

= 50 mA, 1.5V < V

LDOm

< 3.0V

10Hz < f < 100kHz, C

BYP

= 22nF,

C

LDO2

= 1µF, I

LDO2

= 50 mA, 1.2V < V

LDO2

< 1.8V

Nominal value for C

LDOn (6)

1

Range of nominal settings

I

LDOn (6)

= 1mA, T

A

= 25°C, 2.9V ≤ V

IN

≤ 4.2V

I

LDOn (6)

= 1mA to 100mA, 2.9V ≤ V

IN

≤ 4.2V

I

LDOm (6)

= 150mA, V

IN

= V

LDOm

+ V

Dm

I

LDO2

= 100mA, V

IN

= V

LDO2

+ V

D2

200

2.1

1.3

10

8

53

dB

61

67

µV

RMS

47

µF

7.2

mV

4.8

25

mV

20

1.5

1.2

-3

-3.5

150

100

±1.0

3.3

1.8

+3

+3.5

200

mV

150

mA

V

%

Symbol

Conditions

Min

Typ

Max

Units

Output Voltage Accuracy

Dropout Voltage

Line Regulation

Load Regulation

DV

LOAD

PSRR

m (6)

Power Supply Rejection Ratio

PSRR

2

e

n-LDOm (6)

Output Voltage Noise

e

n-LDO2

Minimum LDO Capacitor

(1)

ADC Specifications

Resolution

Offset

Gain Error

Integral Non-Linearity

AD

RES

AD

OFFSET

AD

GAIN_ERR

INL

C

LDO(MIN)

8

V

LDO4

= 3.3V

V

LDO4

= 3.3V

V

LDO4

= 3.3V

1

0.1

1

bits

LSB

%

LSB

4

SC667

Electrical Characteristics (continued)

Parameter

Symbol

Conditions

Min

Typ

Max

Units

Digital Input Electrical Specifications (PWM, EN, SDA, SCL)

Input High Threshold

(7) (8)

Input Low Threshold

(7) (8)

Input High Current

Input Low Current

V

IH

V

IL

I

IH

I

IL

V

IN

= 5.5V

V

IN

= 2.9V

V

IN

= 5.5V

V

IN

= 5.5V

-1

1.6

0.4

+1

V

µA

Digital Output Electrical Specification (IRQ)

IRQ Output Low Level

PWM Input Specification (PWM)

PWM Input Frequency

f

PWM

0.2

50

kHz

V

OL

I

IRQ

≤ 3mA

0.4

V

I

2

C Interface

Interface complies with slave mode I

2

C interface as described by Philips I

2

C specification version 2.1 dated January, 2000.

Digital Input Voltage

(7)

SDA Output Low Level

Digital Input Current

Hysteresis of Schmitt Trigger Inputs

Maximum Glitch Pulse Rejection

I/O Pin Capacitance

I

2

C Timing

Clock Frequency

(7)

SCL Low Period

(7) (8)

SCL High Period

(7) (8)

Data Hold Time

(7) (8)

Data Setup Time

(7) (8)

Setup Time for Repeated

START Condition

(7) (8)

Hold Time for Repeated

START Condition

(7) (8)

Setup Time for STOP Condition

(7) (8)

Bus-Free Time Between

STOP and START

(7) (8)

Interface Start-up Time

(7) (8)

f

SCL

t

LOW

t

HIGH

t

HD_DAT

t

SU_DAT

t

SU_STA

t

HD_STA

t

SU_STO

t

BUF

t

EN

Bus start-up time after EN pin is pulled high

1.3

0.6

0

100

0.6

1.3

900

400

440

kHz

µs

ns

µs

I

B-IN

V

HYS

t

SP

C

IN

V

B-IL

V

B-IH

I

DIN

(SDA) ≤ 3mA

-0.2

0.1

50

10

1.6

0.4

0.2

0.4

V

µA

V

ns

pF

5

SC667

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