SC644 SEMTECH [Semtech Corporation], SC644 Datasheet
SC644
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SC644 Summary of contents
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... 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 ...
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... 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 ...
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... 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 ...
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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 ...
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... 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 ...
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... 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 ...
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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 ...
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... 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 ...
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... 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 ...
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... 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 ...
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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 ...
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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 ...
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... 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� ...
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... 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) ...
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... 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 ...
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... 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: • ...
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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 ...
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... 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) ...
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... 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 ...
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... Bit D5 Backlight Current (mA) This bit is unused and is always a zero See note 0 See note See note SC644 20 ...
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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 ...
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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 ...
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... 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 ...
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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 ...
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... 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 ...
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... 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 ...