c644ultrt Semtech Corporation, c644ultrt Datasheet

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c644ultrt

Manufacturer Part Number
c644ultrt
Description
Light Management Unit With 4 Ldos And Sempulse Interface
Manufacturer
Semtech Corporation
Datasheet
POWER MANAGEMENT
Features
Applications
Typical Application Circuit
October 8, 2009
Input supply voltage range — 2.9V to 5.5V
Very high efficiency charge pump driver system with
three modes — x, .5x, and 2x
Six programmable current sinks with 29 increments
from 0mA to 25mA
Four programmable 200mA low-noise LDO regulators
Programmable driver configurations for main and
sub-display backlight
Fade-in/fade-out feature for main and sub display
backlight
SemPulse single wire interface
Backlight current accuracy — ±.5% typical
Backlight current matching — ±0.5% typical
Automatic sleep mode with LEDs off
Shutdown current — 0.µA typical
Ultra-thin package — 3 x 3 x 0.6 (mm)
Lead free and halogen free
WEEE and RoHS compliant
Cellular phones, smart phones, and PDAs
LCD display modules
Portable media players
Digital cameras and GPS units
Display backlighting and LED indicators
V
BAT
= 2.9V to 5.5V
4.7µF
SemPulse
Interface
22nF
IN
SPIF
BYP
AGND
PGND
© 2009 Semtech Corporation
2.2µF
SC644
LDO1
LDO2
LDO3
LDO4
OUT
2.2µF
BL1
BL2
BL3
BL4
BL5
BL6
Description
The SC644 is a high efficiency charge pump LED driver
using Semtech’s proprietary charge pump technology.
Performance is optimized for use in single cell Li-ion
battery applications.
Display backlighting is provided through six matched
current sinks with integrated fade-in and fade-out con-
trols. The LEDs can be driven as a single set or as two
different sets (for main and sub displays) with indepen-
dent controls. Four low noise, low dropout (LDO) regulators
are provided to supply power for camera module I/O and
other peripheral circuits.
The SC644 uses the proprietary SemPulse
interface. This interface controls all functions of the device,
including backlight currents and LDO voltage outputs.
The single wire interface minimizes microcontroller and
interface pin counts.
The SC644 enters sleep mode when all the LED drivers are
disabled. In this mode, the quiescent current is reduced
while the device continues to monitor the SemPulse inter-
face. Any combination of LDOs may be enabled when in
sleep mode.
4 LDOs and SemPulse
4.7µF
1.0µF
Light Management Unit with
1.0µF
Main Backlight
1.0µF
1.0µF
US Patents: 6,504,422; 6,794,926
V
V
V
LDO1
LDO2
LDO3
= 1.5V to 3.3V
= 1.2V to 1.8V
= 1.5V to 3.3V
Motor
®
Backlight
Sub
Interface
SC644
®
single wire



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c644ultrt Summary of contents

Page 1

... SPIF 4.7µF BL1 BL2 BYP BL3 BL4 BL5 AGND BL6 PGND LDO1 LDO2 LDO3 LDO4 1.0µF 1.0µF 2.2µF 2.2µF © 2009 Semtech Corporation SC644 ® Interface ® single wire Sub Main Backlight Backlight V = 1.5V to 3.3V LDO1 V = 1.2V to 1.8V LDO2 V = 1.5V to 3.3V LDO3 Motor 1.0µF 1.0µ ...

Page 2

... JA Marking Information 644 yyww xxxx yyww = Date Code xxxx = Semtech Lot No. Ordering Information Device SC644ULTRT 16 SC644EVB Notes: LDO1 15 () Available in tape and reel only. A reel contains 3,000 devices. (2) Lead-free packaging only. Device is WEEE and RoHS compliant, LDO2 14 and halogen free. ...

Page 3

Absolute Maximum Ratings IN, OUT ( ...

Page 4

Electrical Characteristics (continued) Parameter Charge Pump Electrical Specifications (Cont.) .5x Mode to 2x Mode Falling Transition Voltage 2x Mode to .5x Mode Hysteresis Current Sink Off-State Leakage Current Pump Frequency LDO Electrical Specifications LDO, LDO3, and LDO4 Voltage Setting Range ...

Page 5

Electrical Characteristics (continued) Parameter Digital I/O Electrical Specifications (SPIF) Input High Threshold (9) Input Low Threshold (9) Input High Current Input Low Current SemPulse Electrical Specifications (SPIF) SemPulse Start-up Time (0) Bit Pulse Duration (9) Duration Between Bits (9) Hold ...

Page 6

Typical Characteristics Battery Current (6 LEDs) — 25mA Each V = 3.50V 150mA, 25 °C OUT OUT 300 260 220 180 140 100 4.2 3.9 3.6 V (V� IN Battery Current (6 LEDs) — 12mA Each V = ...

Page 7

Typical Characteristics (continued) PSRR vs. Frequency — 1.8V V =3.7V, V =1.8V 50mA IN OUT OUT 0 -10 -20 -30 -40 -50 -60 -70 10 100 Frequency (Hz� Line Regulation (LDO2 1mA 1.2V and ...

Page 8

Typical Characteristics (continued) Load Regulation (LDO2) V =3.6V, 25° 1.2V -10 -15 -20 - (mA� LDO LDO Load Transient Response (3.3V) V =3.7V, V =3.3V 00mA, 25°C IN LDO LDO ...

Page 9

Typical Characteristics (continued) Ripple — 1X Mode V =3.8V, 6 Backlights — each, 25° (00mV/div (00mV/div) OUT I (20mA/div) BL Time (20µ���i�� ���i�� ��i�� Ripple — 2X Mode V =2.9V, 6 Backlights — 5 ...

Page 10

Pin Descriptions Pin # Pin Name  IN 2 PGND 3 BL3 4 BL2 5 BL 6 BL4 7 BL5 8 BL6 9 AGND 0 LDO4  LDO3 2 SPIF 3 BYP 4 LDO2 5 LDO 6 OUT 7 C2+ ...

Page 11

Block Diagram SPIF 12 SemPulse Digital Interface and Logic Control LDO BYP 13 Voltage Reference 2 PGND AGND 9 C2+ C1+ C1- C2 Fractional Charge Pump (1x, 1.5x, 2x) Oscillator Current Setting ...

Page 12

Applications Information General Description This design is optimized for handheld applications sup- plied from a single cell Li-Ion and includes the following key features: • A high efficiency fractional charge pump that supplies power to all LEDs • Six matched ...

Page 13

Applications Information (continued) Main and Sub Backlight Bank Configuration The six LED backlight drivers can be configured as a single bank or as two independent banks — one dedicated for a main display and the other for a sub display. ...

Page 14

Applications Information (continued) Table 1 — Fade-In from Off State Command Action Sequence . Disable fade for Write to register 09h the bank 2. Set Main and/or Write to register 0h Sub backlights to and or 02h () 0.5mA 3. ...

Page 15

Applications Information (continued) Protection Features The SC644 provides several protection features to safe- guard the device from catastrophic failures. These features include: • Output Open Circuit Protection • Over-Temperature Protection • Charge Pump Output Current Limit • LDO Current Limit ...

Page 16

Applications Information (continued) PCB Layout Considerations The layout diagram in Figure 2 illustrates a proper two- layer PCB layout for the SC644 and supporting components. Following fundamental layout rules is critical for achieving the performance specified in the Electrical Characteristics ...

Page 17

SemPulse Interface Introduction SemPulse is a write-only single wire interface. It provides access registers that control device functional- ity. Two sets of pulse trains are transmitted to generate a complete SemPulse command. The first pulse ...

Page 18

SemPulse Interface (continued) SemPulse Timing Diagrams The SemPulse single wire interface is used to enable or disable the device and configure all registers (see Figure 5). The timing parameters refer to the digital I/O electrical specifications. SPIF t = ...

Page 19

Register Map (1) Address D5 D4 (2) 00h BL6EN BL5EN 0h 0 (3) MBL4 02h 0 SBL4 (3) 05h 0 0 (3) (3) 06h 0 0 (3) (3) 07h 0 0 (3) (3) 08h 0 0 (3) (3) 09h SFADE ...

Page 20

Register Map (continued) MBL4 through MBL0 [D4:D0] These bits are used to set the current for the main back- light current sinks. All enabled current sinks will sink the same current as shown in Table 4. Table 4 — Main ...

Page 21

Register Map (continued) SBL4 through SBL0 [D4:D0] These bits are used to set the current for the sub backlight current sinks. All enabled current sinks will sink the same current as shown in Table 5. Table 5 — Sub Backlight ...

Page 22

Register Map (continued) LDO2 Control Register (06h) This register is used to enable LDO2 and set its output voltage level. Bits [D5:D3] These bits are unused and are always zeroes. LDO2V2 through LDO2V0 [D2:D0] These bits are used to set ...

Page 23

Register Map (continued) LDO4 Control Register (08h) This register is used to enable LDO4 and set its output voltage level. Bits [D5:D4] These bits are unused and are always zeroes. LDO4V3 through LDO4V0 [D3:D0] These bits are used to set ...

Page 24

Register Map (continued) SFADE1 and SFADE0 [D5:D4] These bits are used to set the rise/fall rate between two backlight currents for the sub display as show in Table . For the fade feature to be active, the SFADE bit must ...

Page 25

Outline Drawing — MLPQ-UT-20 3x3 A PIN 1 INDICATOR (LASER MARK) A aaa NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE ...

Page 26

Land Pattern — MLPQ-UT-20 3x3 NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE ...

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