sc604a Semtech Corporation, sc604a Datasheet
sc604a
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sc604a Summary of contents
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... POWER MANAGEMENT OBJECTIVE -NOVEMBER Description 9, 2000 The SC604A is a very high efficiency charge pump white LED driver driver from the mAhXLife optimized for Li-Ion battery applications. The four (4) LED outputs are current matched for consis- tent LED brightness. Extremely low battery current is achieved by automatically reconfiguring the charge pump to match circuit conditions ...
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... SC604A ...
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... SC604A =25°C, LED V = 3.4V www.semtech.com ...
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... LEDs and return via the I pins. LED 2005 Semtech Corp. Input Current The total input current of the SC604A is a function of resistor (I SET LED the sum of the LED currents, the charge pump mode and the quiescent current. The quiescent current trend ...
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... SC604A ...
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... SC604A ILED1 16 GND 12 Current Set Detect ISET 5 1.22V Bandgap Voltage Schmitt Buffer CTRL0 2 Schmitt Buffer CTRL1 3 Schmitt Buffer CTRL2 ...
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... The SC604A efficiency and battery current are shown in the plots that follow on page 8. For this example, 4 LEDs are matched at 15mA each. The battery current remains low at 63mA well into the Li-Ion battery range as indicated in the plot by a boundary box. The SC604A uses 1x mode ( ...
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... Efficiency Comparison for 4 LEDs with 15mA Each and LED = 3.5V 100 4.2 4.1 4.0 2005 Semtech Corp. Competition 1.5x mode Semtech 1x mode 90% of Li-Ion battery life 3.9 3.8 3.7 3.6 VIN [V] Semtech 1x mode Competition 1.5x mode 90% of Li-Ion battery life 3.9 3.8 3.7 3.6 VIN [V] 8 SC604A Semtech 1.5x mode 3.5 3.4 3.3 3.2 Semtech 1.5x mode 3.5 3.4 3.3 3.2 www.semtech.com ...
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... Typical R Resistance vs. LED Current SET 3 3.5 4 4.5 5 5.5 6 LED Current [mA] 9 SC604A ...
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... LED current can be maintained at ADJ 1.5mA. Figure Bit LED Current Control with Open Drain [ ] SC604A . Parallel combinations are SET www.semtech.com ...
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... SC604A Figure 3 - PWM Example Circuit < I < ...
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... VIN = 4.0V 90 VIN = 4. 100 120 SC604A Efficiency vs. Load at Low Battery VIN = 3.4V VIN = 3.6V VIN = 2. Total Load Current [mA] Quiescent Current Trend Trend for 4 LEDs Total Output Current [mA] www.semtech.com 100 120 100 120 ...
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... Semtech Corp. 100 LED = 3.45V 3.6 3.4 3.2 4.2 100 90 LED = 3.37V 3.6 3.4 3.2 4 3.6 3.4 3.2 4.2 13 SC604A Efficiency for 4 LEDs at 20mA LED = 3.45V 4 3.8 3.6 Input Voltage [V] Efficiency for 4 LEDs at 10mA LED = 3.37V 4 3.8 3.6 3.4 Input Voltage [V] Efficiency for 4 LEDs at 0.5mA LED = 2.91V 4 3.8 3.6 3.4 Input Voltage [V] www.semtech.com 3.4 3.2 3.2 3.2 ...
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... POWER MANAGEMENT Typical Characteristics with 4 LEDs Ripple in 1x Mode for 4 LEDs at 20mA Each Ripple in 1.5x Mode for 4 LEDs at 20mA Each Ripple in 2x Mode for 4 LEDs at 20mA Each 2005 Semtech Corp. 14 SC604A www.semtech.com ...
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... POWER MANAGEMENT Evaluation Board Schematic 2 NEG 2 2005 Semtech Corp ISET ILED1 VOUT ILED2 6 15 VIN ILED3 7 14 C1+ ILED4 SC604A www.semtech.com ...
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... Jumpers provide High/Low settings for the control bits. RSET resistor Evaluation board has 1M potentiometer in place of R1. Series input resistor for studying effects of input resistance. Resistor for analog brightness control. Apply test signal 1.2V at VADJ test point. Banana jacks for power supply. 16 SC604A Bottom View www.semtech.com ...
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... A1 .000 - A2 b .010 D .153 D1 .074 E E .153 E1 .074 e L .018 N aaa bbb A2 SEATING PLANE e/2 N LxN E bxN bbb D/2 17 SC604A DIMENSIONS INCHES MILLIMETERS NOM MAX MIN NOM MAX - - .040 0.80 1. .002 0.00 0.05 (.008 (0.20) - .012 .014 0.25 0.30 0.35 .157 .161 3.90 4.00 4.10 .085 .089 1.90 2.15 2.25 .157 ...
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... Phone: (805) 498-2111 FAX (805)498-3804 2005 Semtech Corp. K DIM Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Visit us at: www.semtech.com 18 SC604A DIMENSIONS INCHES MILLIMETERS (.148) (3.75) .106 2.70 .091 2.30 .091 2.30 .026 0.65 .016 0.40 .041 1.05 .189 4.80 www.semtech.com ...