SC644 SEMTECH [Semtech Corporation], SC644 Datasheet

no-image

SC644

Manufacturer Part Number
SC644
Description
Manufacturer
SEMTECH [Semtech Corporation]
Datasheet

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
SC644ULTRT
Manufacturer:
SEMTECH/美国升特
Quantity:
20 000
Company:
Part Number:
SC644ULTRT
Quantity:
900
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


Related parts for SC644

SC644 Summary of contents

Page 1

... 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 ...

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. BYP 13 SPIF ...

Page 3

... Min Typ 2.9 = 4.2V 0. 90 (2) IN 300 ( 0.5mA, 6 LEDs on 2.6 = 25mA, 6 LEDs on 4.8 = 25mA, 6 LEDs on 5.6 BLn  ±.5 -3.5 ±0.5 = 3.2V 3.22 OUT = 3.2V 250 OUT SC644 T +85 ≤ ≤ 5.5 ≤ ≤ 5.25 ≤ ≤ OUT ≤ .0 F (°C/ 4.7µF, IN OUT Max Units 5.5 V 2.0 µA 35 µA 450 ...

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

... Dropout does not apply to LDO2 since it has a maximum output voltage LDOm Min Typ . 0.75 0.75 500 500 0 0 300  5.7 OUT OVP 2.7 IN 800 = 3.2V for white LEDs. OUT SC644 Max Units V 0 µA + µA ms 250 µs 250 µs 5000 µs µ °C °C 6 ...

Page 6

... Backlight Efficiency (6 LEDs) — 25mA Each V = 3.50V 150mA, 25 °C OUT OUT 3.9 3.6 3.3 V (V� IN Backlight Efficiency (6 LEDs) — 12mA Each V = 3.37V 72mA, 25 °C OUT OUT 3.9 3.6 3.3 V (V� IN Backlight Efficiency (6 LEDs) — 4.0mA Each V = 3.21V 24mA, 25°C OUT OUT 3.9 3.6 3.3 V (V� IN SC644 3.0 2.7 3.0 2.7 3.0 2.7 6 ...

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

... Time (20µ���i�� ���i�� ��i�� Output Short Circuit Current Limit V =0V, V =4.2V, 25°C OUT IN (V/div) Time (1m���i�� ���i�� ��i�� SC644 160 200 8 ...

Page 9

... Time (20µ���i�� ���i�� ��i�� Output Open Circuit Protection V =3.7V, 25° (500mV/div) BL 5.42V V (1V/div) OUT I (20mA/div) BL Time (200µ���i�� ���i�� SC644 ��i�� 9 ...

Page 10

... Charge pump output — all LED anode pins should be connected to this pin Positive connection to bucket capacitor 2 Positive connection to bucket capacitor  Negative connection to bucket capacitor  Negative connection to bucket capacitor 2 Thermal pad for heatsinking purposes — connect to ground plane using multiple vias — not con- nected internally SC644 0 ...

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

... Main/Sub Backlight Fade register (09h). This procedure must be followed regardless of which backlight grouping configuration is being used. Note that it is only necessary to set the BLEN bits for the main or sub display that is required to fade. SC644 Imme�iate bright le�el No Write towar� ...

Page 14

... For more details about the Fade-in/Fade-out function, Any value from 0h through 3Fh refer to the SC644 Backlight Driver Software User’s Guide and SemPulse Interface Specification document and to the Any value from 05h associated software drivers available for this device through Fh (contact your sales office for more details) ...

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 • LED Float Detection ...

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 table. The following guidelines are recommended when developing a PCB layout: • ...

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

... HI HOLDA t < t HImax Address is set to Data written is register 02h 000010 Interrupt duration t > HImax HOLDA SC644 Data is written HOLDD t LO Data written is 000011 HOLDD t < t LOmax Address is set to register 03h (address and data are now out of order) ...

Page 19

... LDO2V0 (3) LDO3V3 LDO3V2 LDO3V LDO3V0 LDO4V3 LDO4V2 LDO4V LDO4V0 SFADE MFADE MFADE0 MFADE 0 MB2 MB MB0 (3) SC644 Reset Description Value 00h Backlight Enable 00h Main Backlight Current 00h Sub Backlight Current 00h LDO 00h LDO2 00h LDO3 00h LDO4 00h Main/Sub Backlight Fade ...

Page 20

... Bit D5 Backlight Current (mA) This bit is unused and is always a zero See note  0 See note   See note  SC644 20 ...

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

... MFADE and MFADE0 bits. The total fade time is given by the number of steps  .5V between old and new backlight values (see Table 4), mul- tiplied by the rate of fade in ms/step. Fade Feature Rise/ MFADE0 Fall Rate (ms/step SC644 ...

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

... DIM MIN MAX MIN MAX NOM NOM - - A .020 .024 0.50 0. .000 .002 0.00 0.05 (.006) (0.152 .006 .008 .010 0.15 0.20 0.25 D .114 .118 .122 2.90 3.00 3.10 D1 .061 .067 .071 1.55 1.70 1.80 E .114 .118 .122 2.90 3.00 3.10 E1 .061 .067 .071 1.55 1.70 1.80 e .016 BSC 0.40 BSC L .012 .016 .020 0.30 0.40 0. aaa .003 0.08 bbb .004 0.10 SC644 25 ...

Page 26

... FUNCTIONAL PERFORMANCE OF THE DEVICE. Contact Information DIM Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 9302 Phone: (805) 498-2 Fax: (805) 498-3804 www.semtech.com SC644 DIMENSIONS INCHES MILLIMETERS (.114) (2.90) .083 2.10 .067 1.70 .067 1.70 .016 0.40 .004 0.10 .008 0.20 .031 0.80 .146 3 ...

Related keywords