sc656 Semtech Corporation, sc656 Datasheet
sc656
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sc656 Summary of contents
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... September 24, 2009 Backlight Driver for 7 LEDs with Charge Pump and PWM Control Description The SC656 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. The device provides backlight current using up to seven matched current sinks ...
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... JA Marking Information 656 yyww xxxx yyww = Date Code xxxx = Semtech Lot Number Ordering Information Device SC656ULTRT SC656EVB 16 Notes: () Available in tape and reel only. A reel contains 3,000 devices. C2- 15 (2) Lead-free package only. Device is WEEE and RoHS compliant, and GND halogen free. 14 BANK2 ...
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... C = 2.2µF, (ESR = 0.03Ω), IN IN OUT 2 Min Typ 0. 2.5 = 4.99kΩ ISETM 2.8 = 4.99kΩ ISETM 3.0 = 4.99kΩ ISETM 75 ≥ 4kΩ 0.5 ISETX to I 00 FS_BL ISETX -3.5 ±0.5 ±.5 0.2 FS_BL SC656 ≤ +85 A ≤ .0 (2) F (°C/ (3) Max Units 2 µ A kHz µs 3 ...
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Electrical Characteristics (continued) Parameter Symbol Current Transition Settling Time ENM/ENS Low Time x Mode to .5x Mode Falling Transition Voltage .5x Mode to 2x Mode Falling Transition Voltage Current Sink Off-State Leakage Current Charge Pump Frequency Output Short Circuit Current ...
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... I = 175mA, 25°C OUT OUT 4.2 3.9 3.6 3.3 V (V� IN Backlight Matching (7 LEDs) — 12mA Each V = 3.42V 84mA, 25°C OUT OUT 4.2 3.9 3.6 3.3 V (V� IN Backlight Matching (7 LEDs) — 5mA Each V = 3.28V 35mA, 25°C OUT OUT 4.2 3.9 3.6 3.3 V (V� IN SC656 3 2.7 3 2.7 3 2.7 5 ...
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... Backlight Current (7 LEDs) — 25mA Each V = 3.56V 175mA, 25°C OUT OUT 4.2 3.9 3.6 3.3 V (V� IN Backlight Current (7 LEDs) — 12mA Each V = 3.42V 84mA, 25°C OUT OUT 4.2 3.9 3.6 3.3 V (V� IN Backlight Current (7 LEDs) — 5mA Each V = 3.28V 35mA, 25°C OUT OUT 4.2 3.9 3.6 3.3 V (V� IN SC656 3 2.7 3 2.7 3 2.7 6 ...
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Typical Characteristics (continued) PWM Accuracy — 4. 4.2V 4.99kΩ, Calculated I IN ISET 50kHz 8 32kHz 4 200Hz Mea�ure� PWM Accuracy — 3. 3.7V, ...
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... V (00mV/div (00mV/div) OUT ���i�� ��i�� SC656 Ripple — 1X Mode V =4.2V 5.56kΩ, 7 Backlights — each, 25°C IN ISET Time (10µ���i�� ���i�� ...
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... DC Backlight Current — 200Hz PWM V = 3.7V, 50% duty cycle 4.99kΩ 0mA IN ISET BL 0mA— (2V/div) 0V— Time (1m���i�� ���i�� ��i�� SC656 9 ...
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... Positive connection to bucket capacitor 8 C2+ Positive connection to bucket capacitor 2 9 OUT Charge pump output — all LED anode pins are connected to this pin. 20 ENM Enable pin for the main display LED bank — also used as the PWM dimming control input for this bank SC656 0 ...
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Block Diagram IN 2 GND 14 ENM 20 ISETM 3 ISETS 4 ENS 1 BANK2 13 Configuration BANK1 12 C1+ C1- C2+ C2 Fractional Charge Pump IN (1x, 1.5x, 2x) Oscillator Control Interface, Level Converter, Digital ...
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... For applications which do not require the full 75mA output capability of the SC656 , a lower cost and smaller size capacitor option may be used. The µF capacitor in Table may be used with no loss in accuracy, for up to 90mA of output current. Table 1 — ...
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... When the ENM and ENS pins are both held low for 5ms or less, the device will not shutdown. ) Protection Features BL The SC656 provides several protection features to safe- guard the device from catastrophic failures. These features include: • Output Open Circuit Protection • ...
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... PCB Layout Considerations The layout diagram in Figure 2 illustrates a proper two layer PCB layout for the SC656 and supporting compo- nents. Following fundamental layout rules is critical for achieving the performance specified in the Electrical Characteristics table. The following guidelines are rec- ...
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... This will help prevent unintended clocking of the PWM. The layout should be routed to achieve the least possible trace to trace capaci- tance between ENM and ENS. Also, minimize trace capacitance between ENM or ENS and any high speed signals. Figure 4 — Layer 2 SC656 , C and IN OUT 5 ...
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... NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. 3. DAP IS 1.90 x 1.90mm SEATING PLANE C D1 LxN E/2 bxN bbb SC656 DIMENSIONS INCHES MILLIMETERS DIM MIN NOM MAX MIN NOM - - A .020 .024 0. .000 .002 0. ...
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... FAILURE MAY COMPROMISE THE THERMAL AND/OR 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 DIMENSIONS INCHES MILLIMETERS (.114) (2.90) .083 2.10 .067 1.70 .067 1.70 ...