SC662

SC662 SEMTECH | Alldatasheet

Document overview

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Technical content

Features

Input supply voltage range — 2.9V to 5.5V Very high efficiency charge pump driver system with three modes — 1x, 1.5x and 2x Six programmable current sinks — 0mA to 25mA Up to three LED grouping options Fade-in/fade-out feature for main LED bank Selectable charge pump frequency — 250kHz/1MHz SemPulse® single wire interface Backlight current accuracy — ±1.5% typical Backlight current matching — ±0.5% typical LED float detection Automatic sleep mode with all LEDs off Sleep mode quiescent current — 60µA typical Shutdown current — 0.1µA typical Ultra-thin package — 2 x 2 x 0.6 (mm) Lead-free and halogen-free WEEE and RoHS compliant

Applications

Cellular phones, smart phones, and PDAs LCD modules Portable media players Digital cameras Personal navigation devices Display/keypad backlighting and LED indicators

Description

The SC662 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 charge pump provides backlight current utilizing six matched current sinks. The load and supply conditions determine whether the charge pump operates in 1x, 1.5x, or 2x mode. An optional fading feature that gradually adjusts the backlight current is provided to simplify control software. The SC662 uses the proprietary SemPulse ® single wire interface to control all functions of the device, including backlight currents. The single wire interface minimizes microcontroller and interface pin counts. The six LEDs can be grouped in up to three separate banks that can be independently controlled. The charge pump switches at 1MHz or 250kHz, and the frequency is selectable using the SemPulse interface. Both 1MHz and 250kHz frequencies are supported by 0402 size (1005 metric) ceramic capacitors. The SC662 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 interface. November 30, 2010 Typical Application Circuit

T Device Package SC662ULTRT(1)(2) MLPQ-UT-14 2×2 SC662EVB Evaluation Board ...FB yw FB = SC662ULTRT yw = date code Pin Configuration Marking Information

Ordering Information

Notes: (1) Available in tape and reel only. A reel contains 3,000 devices. (2) Lead-free packaging only. Device is WEEE and RoHS compliant, and halogen-free. MLPQ-UT-14; 2x2, 14 LEAD θJA = 78°C/W

Parameter Symbol Conditions Min Typ Max Units Supply Specifications Shutdown Current IQ(OFF) 0.1 2 µA Total Quiescent Current IQ All outputs disabled, SPIF = VIN (2) 60 µA 1x mode, all LEDs on, IBLn = 0.5mA 0.9 mA1x mode, all LEDs on, IBLn = 25mA 1.5 1.5x or 2x charge pump mode, all LEDs on, IBLn = 25mA 2 Charge Pump Electrical Specifications Maximum Total Output Current IOUT(MAX) VIN > 2.9V, sum of all active LED currents, VOUT(MAX) = 4.2V 150 mA Backlight Current Setting IBLn Nominal setting for BL1 thru BL6 0 25 mA Backlight Current Matching IBL-BL IBLn = 12mA(3) -3.5 ±0.5 +3.5 % Backlight Current Accuracy IBL_ACC IBLn = 12mA ±1.5 % Mode Transition (Falling) Input Voltage — 1x Mode to 1.5x Mode VTRANS1x IOUT = 72mA, IBLn = 12mA, VOUT = 3.22V 3.28 V 1.5x Mode to 1x Mode Hysteresis VHYST1x IOUT = 72mA, IBLn = 12mA, VOUT = 3.22V, fPUMP = 250kHz 250 mV Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not recommended. NOTES: (1) Tested according to JEDEC standard JESD22-A114 (2) Calculated from package in still air, mounted to 3 x 4.5 (in), 4 layer FR4 PCB per JESD51 standards. Absolute Maximum Ratings Unless otherwise noted, TA = +25°C for Typ, -40°C to +85°C for Min and Max, TJ(MAX) = 125°C, VIN = 3.7 V, CIN= C1= C2= COUT = 1.0µF (ESR = 0.03Ω)(1) Recommended Operating Conditions Thermal Information Thermal Resistance, Junction to Ambient (2) (°C/W) . . 78

Electrical Characteristics

Parameter Symbol Conditions Min Typ Max Units Charge Pump Electrical Specifications (continued) Mode Transition (Falling) Input Voltage — 1.5x Mode to 2x Mode VTRANS1.5x IOUT = 72mA, IBLn = 12mA, VOUT = 4.2V(4), fPUMP = 250kHz 3.14 V Current Sink Off-State Leakage Current IBLn(off ) VIN = VBLn = 4.2V 0.1 1 µA Charge Pump Frequency fPUMP Bit FSEL = 0 250 kHz Bit FSEL = 1 1 MHz Fault Protection Specifications Output Short Circuit Current Limit IOUT(SC) OUT pin shorted to GND 125 mA VOUT > 2.5V 300 Under Voltage Lockout VUVLO-OFF Increasing VIN 2.3 V VUVLO-HYS Hysteresis 75 mV Over-Voltage Protection VOVP OUT pin open circuit, VOUT = VOVP, rising threshold 5.7 6.0 V Over-Temperature Threshold TOT Rising temperature 165 °C TOT-HYS Hysteresis 20 °C Electrical Characteristics (continued)

Parameter Symbol Conditions Min Typ Max Units SemPulse Interface Input High Threshold VIH VIN = 5.5V 1.4 V Input Low Threshold VIL VIN = 2.9V 0.4 V Input High Current IIH VIN = 5.5V -1 +1 µA Input Low Current IIL VIN = 5.5V -1 +1 µA Start up Time(5) tSU Only required when leaving shutdown mode 1 ms Bit Pulse Duration(6) tHI 0.75 250 µs Duration Between Pulses(6) tLO 0.75 250 µs Hold Time - Address(6) tHOLDA 550 5000 µs Hold Time - Data(6) tHOLDD 550 µs Bus Reset Time (6) tBR 10 ms Shutdown Time (7) tSD 10 ms Notes: (1) Capacitors are MLCC of X5R type. (2) SPIF is high for more than 10ms to place the serial bus in standby mode. (3) Current matching is defined as ± [IBL(MAX) - IBL(MIN] / [IBL(MAX) + IBL(MIN)]. (4) Test voltage is VOUT = 4.2V — a relatively extreme LED voltage — to force a transition during test. Typically VF = 3.2V for white LEDs. (5) The SemPulse start-up time is the minimum time that the SPIF pin must be held high to enable the part before starting communication. (6) The source driver used to provide the SemPulse output must meet these limits. (7) The SemPulse shutdown time is the minimum time that the SPIF pin must be pulled low to shut the part down. Electrical Characteristics (continued)

fPUMP = 1MHz, VOUT = 3.42V, CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C VIN (V) Efficiency (%) 100 Backlight Charge Pump Charge Pump Efficiency (6 LEDs) — 12mA Each fPUMP = 1MHz, VOUT = 3.56V, CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C Efficiency (%) VIN (V) 100 Charge Pump Backlight Charge Pump Efficiency (6 LEDs) — 25mA Each fPUMP = 1MHz, VOUT (see note), CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C VIN (V) Efficiency (%) 100 Charge Pump Backlight Charge Pump Efficiency (6 LEDs) — 5mA Each fPUMP = 250kHz, VOUT = 3.55V, CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C Backlight VIN (V) Efficiency (%) 100 Charge Pump Charge Pump Efficiency (6 LEDs) — 25mA Each fPUMP = 250kHz, VOUT = 3.41V, CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C VIN (V) Efficiency (%) 100 Backlight Charge Pump Charge Pump Efficiency (6 LEDs) — 12mA Each VIN (V) Efficiency (%) 100 Charge Pump Backlight fPUMP = 250kHz, VOUT (see note), CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C Charge Pump Efficiency (6 LEDs) — 5mA Each Notes: (1) Efficiency labels “Charge Pump” and “Backlight” are defined on page 13 under the sub-heading Charge Pump Efficiency. (2) Plots shown for 5mA data have — VOUT = 3.27V when in 1.5X and 2X modes, and VOUT = VIN - 55mV when in 1X mode. VOUT is connected internally to VIN only when the charge pump is in 1X mode and IBL ≤ 5mA. (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (2) (2)

fPUMP = 1MHz, VOUT = 3.41V, CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C VIN (V) Matching (%) Backlight Matching (6 LEDs) — 12mA Each fPUMP = 1MHz, VOUT = 3.55V, CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C VIN (V) Matching (%) Backlight Matching (6 LEDs) — 25mA Each fPUMP = 1MHz, VOUT (see note), CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C VIN (V) Matching (%) Backlight Matching (6 LEDs) — 5mA Each fPUMP = 250kHz, VOUT = 3.55V, CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C VIN (V) Matching (%) Backlight Matching (6 LEDs) — 25mA Each fPUMP = 250kHz, VOUT = 3.41V, CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C VIN (V) Matching (%) Backlight Matching (6 LEDs) — 12mA Each VIN (V) Matching (%) fPUMP = 250kHz, VOUT (see note), CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C Backlight Matching (6 LEDs) — 5mA Each Typical Characteristics (continued) (2) (2) Notes: (1) Efficiency labels “Charge Pump” and “Backlight” are defined on page 13 under the sub-heading Charge Pump Efficiency. (2) Plots shown for 5mA data have — VOUT = 3.27V when in 1.5X and 2X modes, and VOUT = VIN - 55mV when in 1X mode. VOUT is connected internally to VIN only when the charge pump is in 1X mode and IBL ≤ 5mA.

fPUMP = 1MHz, VOUT = 3.41V, CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C VIN (V) Accuracy (%) ACC Max % ACC Min % Backlight Accuracy (6 LEDs) — 12mA Each fPUMP = 1MHz, VOUT = 3.55V, CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C VIN (V) Accuracy (%) ACC Max % ACC Min % Backlight Accuracy (6 LEDs) — 25mA Each VIN (V) Accuracy (%) ACC Max % ACC Min % fPUMP = 1MHz, VOUT (see note), CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C Backlight Accuracy (6 LEDs) — 5mA Each fPUMP = 250kHz, VOUT = 3.55V, CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C ACC Max % VIN (V) Accuracy (%) ACC Min % Backlight Accuracy (6 LEDs) — 25mA Each fPUMP = 250kHz, VOUT = 3.41V, CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C ACC Max % ACC Min % VIN (V) Accuracy (%) Backlight Accuracy (6 LEDs) — 12mA Each VIN (V) Accuracy (%) ACC Min % ACC Max % fPUMP = 250kHz, VOUT (see note), CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C Backlight Accuracy (6 LEDs) — 5mA Each Typical Characteristics (continued) Notes: (1) Efficiency labels “Charge Pump” and “Backlight” are defined on page 13 under the sub-heading Charge Pump Efficiency. (2) Plots shown for 5mA data have — VOUT = 3.27V when in 1.5X and 2X modes, and VOUT = VIN - 55mV when in 1X mode. VOUT is connected internally to VIN only when the charge pump is in 1X mode and IBL ≤ 5mA. (2) (2)

All data taken with TA = 25°C, 6 LEDs @ 15mA each unless otherwise noted. Time (1µsdiv)sdiv)div) VIN (100mV/div) fPUMP = 1MHz, CIN = COUT = C1 = C2 = 0.47µF (0402) Ripple — 1x Mode VOUT (100mV/div) IBL (20mA/div) Time (1µsdiv)sdiv)div) VIN (100mV/div) fPUMP = 1MHz, CIN = COUT = C1 = C2 = 0.47µF (0402) Ripple — 1.5x Mode VOUT (100mV/div) IBL (20mA/div) Time (1µsdiv)sdiv)div) VIN (100mV/div) fPUMP = 1MHz, CIN = COUT = C1 = C2 = 0.47µF (0402) Ripple — 2x Mode VOUT (100mV/div) IBL (20mA/div) Time (2µsdiv)sdiv)div) VIN (100mV/div) fPUMP = 250kHz, CIN = COUT = C1 = C2 = 1.0µF (0402) Ripple — 1x Mode VOUT (100mV/div) IBL (20mA/div) Time (2µsdiv)sdiv)div) VIN (100mV/div) fPUMP = 250kHz, CIN = COUT = C1 = C2 = 1.0µF (0402) Ripple — 1.5x Mode VOUT (100mV/div) IBL (20mA/div) Time (2µsdiv)sdiv)div) VIN (100mV/div) fPUMP = 250kHz, CIN = COUT = C1 = C2 = 1.0µF (0402) Ripple — 2x Mode VOUT (100mV/div) IBL (20mA/div) Typical Characteristics (continued) 0mA 0mA 0mA 0mA 0mA 0mA

Pin # Pin Name Pin Function

1 BL6 Current sink output for backlight LED 6 — leave this pin open if unused

2 SPIF SemPulse single wire interface pin — used to enable/disable the device and to configure all regis- ters (refer to Register Map and SemPulse Interface sections)

3 GND Ground pin

4 C1- Negative connection to bucket capacitor C1

5 C2- Negative connection to bucket capacitor C2

6 C2+ Positive connection to bucket capacitor C2

7 C1+ Positive connection to bucket capacitor C1

8 OUT Charge pump output — all LED anode pins should be connected to this pin

9 IN Battery voltage input

10 BL1 Current sink output for backlight LED 1 — leave this pin open if unused

11 BL2 Current sink output for backlight LED 2 — leave this pin open if unused

12 BL3 Current sink output for backlight LED 3 — leave this pin open if unused

13 BL4 Current sink output for backlight LED 4 — leave this pin open if unused

14 BL5 Current sink output for backlight LED 5 — leave this pin open if unused

T THERMAL PAD Thermal pad for heatsinking purposes — connect to ground plane using multiple vias — not con- nected internally Pin Descriptions

(1x, 1.5x, 2x) C1+ C1- C2+ C2- OUT BL1 BL2 BL3 BL4 IN SPIF GND 7 564 BL5 BL6 Block Diagram

This design is optimized for handheld applications sup - plied from a single Li-ion cell and includes the following key features: A high efficiency fractional charge pump that supplies power to all LEDs. Six matched current sinks that control LED back- lighting current, providing 0mA to 25mA per LED. Up to three independently controlled LED banks. Selectable charge pump frequency — 250kHz or 1MHz options. High Current Fractional Charge Pump The backlight outputs are supported by a high efficiency, high current fractional charge pump output. The charge pump multiplies the input voltage by 1x, 1.5x, or 2x. The output of the charge pump is delivered to the LED anodes. The charge pump switches only in 1.5x and 2x modes and is disabled in 1x mode to save power and improve efficiency. The charge pump switches at a fixed frequency of either 250kHz or 1MHz. The charge pump switching frequency is set via the SemPulse interface by the FSEL bit. The 250kHz setting is selected by setting FSEL = 0, while the 1MHz setting is selected when FSEL = 1. The mode selection circuit automatically selects one of the following modes; 1x, 1.5x, or 2x based on circuit condi- tions such as LED voltage, input voltage, and load current. The 1x mode is the most efficient of the three modes, fol- lowed by 1.5x and 2x modes. Circuit conditions such as low input voltage, high output current, or high LED voltage place a higher demand on the charge pump output. A higher numerical mode (1.5x or 2x) may be needed momentarily to maintain regulation at the OUT pin during intervals of high demand. The charge pump responds to momentary high demands, setting the charge pump to the optimum mode to deliver the output voltage and load current while optimizing efficiency. Hysteresis is provided to prevent mode toggling. The charge pump requires two bucket capacitors. One capacitor must be connected between the C1+ and C1- pins and the other must be connected between the C2+ and C2- pins as shown in the Typical Application Circuit diagram. Bucket capacitors should be equal in value to support current sharing between C1 and C2. COUT , CIN , C1 , and C 2 capacitors with X7R or X5R ceramic dielectric are strongly recommended for their low ESR and superior temperature and voltage characteristics. Y5V capacitors should not be used as their temperature coef - ficients make them unsuitable for this application. LED Backlight Current Sinks The backlight current is set via the SemPulse interface. The current is regulated to one of 32 values between 0mA and 25mA. The step size varies depending upon the current setting. The lowest settings are 0, 50, 100, and 200µA. From 0.5mA to 5mA, the step size is 0.5mA. The step size increases to 1mA for settings between 5mA and 21mA. Steps are 2mA between 21mA and 25mA. The variation in step size allows finer adjustment for dimming functions in the low current setting range and coarse adjustment at higher current settings where small current changes are not visibly noticeable in LED brightness. A zero setting is also included to allow the current sink to be disabled by writing to either the enable bit or the current setting reg- ister for maximum flexibility. All backlight current sinks have matched currents. When there is a variation in the forward voltages (∆VF ) of the LEDs, mis-matched LED voltages do not degrade the accu- racy of the backlight currents. The voltages of all BLn pins are compared, and the lowest of these voltages is used as feedback for setting the voltage regulation at the OUT pin. This is done to ensure that sufficient bias exists for all LEDs. The backlight LEDs default to the off state upon power-up. For backlight applications using less than six LEDs, any unused output must be left open and the unused LED must remain disabled. When writing to the backlight enable register, a zero (0) must be written to the corre - sponding bit of any unused output. Detailed information about programming of the registers is provided in later sections, beginning at SemPulse Interface on page 21. Applications Information

Efficiency of the charge pump is defined as ININ OUTOUT IV IV u u K The input current is equal to the output current multiplied by the charge pump mode plus the quiescent current IIN = IOUT x Mode + IQ, and the output current is equal to the sum of all backlight currents. ModeII BLn OUT u ¦ VOUT, IOUT, VIN, IIN, IQ, and I BLn are terms from the electrical characteristics section. “Mode” is the active boost ratio of the charge pump, equal to 1, 1.5, or 2. Efficiency plots in the Typical Characteristics section provide charge pump efficiency data labeled with “Charge Pump” . Efficiency of the power conversion to the LEDs is defined as ININ BLnFn IV )IV( u u K VF1 through VF6 are the forward voltages of the LEDs. I BL1 through I BL6 are the regulated backlight sink currents flowing in the LEDs. Efficiency plots in the Typical Characteristics section provide LED backlight efficiency data labeled with “Backlight” . Backlight Quiescent Current The quiescent current required to operate all backlights is reduced when each backlight current is set to 5.0mA or less. This low-current mode feature results in improved efficiency under light-load conditions, saving approxi - mately 350µA of bias current. Low-current mode disables and bypasses the internal LDO when the charge pump is in 1x mode, connecting the LED anodes to the supply at VIN. Further reduction in quiescent current will result from using fewer than the maximum number of LEDs. LED Banks The LEDs can be grouped in up to three independently controlled LED banks. Using the SemPulse interface, the six LED drivers can be grouped as described in the Backlight Grouping Configuration subsection. The banks can be used to provide up to three different current options. This can be useful for controlling keypad, display, and auxiliary backlight operation from one SC662 device. The LED banks provide versatility by allowing backlights to be controlled independently. For example, applications that have a main and sub display may also need to supply an indicator LED. The three bank option allows the SC662 to control each function with different current settings. Another application involves backlighting two displays and a keypad, each requiring different brightness settings. A third scenario requires supplying different brightness levels to different types of LEDs (such as RGB) to create display effects. In all applications, the brightness level for each LED can be set independently. Backlight Fade-in / Fade-out Function The SC662 contains register bits that control the fade state of the main bank. When enabled, the fade function causes the main backlights to change brightness by stepping the current incrementally until the target backlight current is reached. Fade begins immediately after the target back - light current is stored in its register. Fade may be enabled for the main bank only. Sub and third banks do not fade. In addition to the 32 programmable backlight current values, there are also 75 non-programmable current steps. The non-programmable steps are active only during a fade operation to provide for a very smooth change in backlight brightness. Backlight current steps proceed at a program- mable fade rate of 2, 4, or 6ms. The exact length of time used to fade between any two backlight values is determined by multiplying the fade rate by the number of steps between the old and new backlight values. The fade time can be cal- culated from the data provided in Table 1 on page 15. Figures 2 through 6 on page 16 provide additional infor - mation about the fade process. Each figure represents one linear segment of the overall fade range shown in Applications Information (continued)

Starting Value (mA) 25.0 106 105 104 102 96 90 88 84 80 76 72 68 64 60 52 47 42 38 34 30 26 24 22 20 18 16 14 12 10 8 4 0 23.0 102 101 100 98 92 86 84 80 76 72 68 64 60 56 48 43 38 34 30 26 22 20 18 16 14 12 10 8 6 4 0 4 21.0 98 97 96 94 88 82 80 76 72 68 64 60 56 52 44 39 34 30 26 22 18 16 14 12 10 8 6 4 2 0 4 8 20.0 96 95 94 92 86 80 78 74 70 66 62 58 54 50 42 37 32 28 24 20 16 14 12 10 8 6 4 2 0 2 6 10 19.0 94 93 92 90 84 78 76 72 68 64 60 56 52 48 40 35 30 26 22 18 14 12 10 8 6 4 2 0 2 4 8 12 18.0 92 91 90 88 82 76 74 70 66 62 58 54 50 46 38 33 28 24 20 16 12 10 8 6 4 2 0 2 4 6 10 14 17.0 90 89 88 86 80 74 72 68 64 60 56 52 48 44 36 31 26 22 18 14 10 8 6 4 2 0 2 4 6 8 12 16 16.0 88 87 86 84 78 72 70 66 62 58 54 50 46 42 34 29 24 20 16 12 8 6 4 2 0 2 4 6 8 10 14 18 15.0 86 85 84 82 76 70 68 64 60 56 52 48 44 40 32 27 22 18 14 10 6 4 2 0 2 4 6 8 10 12 16 20 14.0 84 83 82 80 74 68 66 62 58 54 50 46 42 38 30 25 20 16 12 8 4 2 0 2 4 6 8 10 12 14 18 22 13.0 82 81 80 78 72 66 64 60 56 52 48 44 40 36 28 23 18 14 10 6 2 0 2 4 6 8 10 12 14 16 20 24 12.0 80 79 78 76 70 64 62 58 54 50 46 42 38 34 26 21 16 12 8 4 0 2 4 6 8 10 12 14 16 18 22 26 11.0 76 75 74 72 66 62 58 54 50 46 42 38 34 30 22 17 12 8 4 0 4 6 8 10 12 14 16 18 20 22 26 30 10.0 72 71 70 68 62 58 54 50 46 42 38 34 30 26 18 13 8 4 0 4 8 10 12 14 16 18 20 22 24 26 30 34 9.0 68 67 66 64 58 54 50 46 42 38 34 30 26 22 14 9 4 0 4 8 12 14 16 18 20 22 24 26 28 30 34 38 8.0 64 63 62 60 54 50 46 42 38 34 30 26 22 18 10 5 0 4 8 12 16 18 20 22 24 26 28 30 32 34 38 42 7.0 59 58 57 55 49 45 41 37 33 29 25 21 17 13 5 0 5 9 13 17 21 23 25 27 29 31 33 35 37 39 43 47 6.0 54 53 52 50 44 40 36 32 28 24 20 16 12 8 0 5 10 14 18 22 26 28 30 32 34 36 38 40 42 44 48 52 5.0 46 45 44 42 36 32 28 24 20 16 12 8 4 0 8 13 18 22 26 30 34 36 38 40 42 44 46 48 50 52 56 60 4.5 42 41 40 38 32 28 24 20 16 12 8 4 0 4 12 17 22 26 30 34 38 40 42 44 46 48 50 52 54 56 60 64 4.0 38 37 36 34 28 24 20 16 12 8 4 0 4 8 16 21 26 30 34 38 42 44 46 48 50 52 54 56 58 60 64 68 3.5 34 33 32 30 24 20 16 12 8 4 0 4 8 12 20 25 30 34 38 42 46 48 50 52 54 56 58 60 62 64 68 72 3.0 30 29 28 26 20 16 12 8 4 0 4 8 12 16 24 29 34 38 42 46 50 52 54 56 58 60 62 64 66 68 72 76 2.5 26 25 24 22 16 12 8 4 0 4 8 12 16 20 28 33 38 42 46 50 54 56 58 60 62 64 66 68 70 72 76 80 2.0 22 21 20 18 12 8 4 0 4 8 12 16 20 24 32 37 42 46 50 54 58 60 62 64 66 68 70 72 74 76 80 84 1.5 18 17 16 14 8 4 0 4 8 12 16 20 24 28 36 41 46 50 54 58 62 64 66 68 70 72 74 76 78 80 84 88 1.0 14 13 12 10 4 0 4 8 12 16 20 24 28 32 40 45 50 54 58 62 64 66 68 70 72 74 76 78 80 82 86 90 0.5 10 9 8 6 0 4 8 12 16 20 24 28 32 36 44 49 54 58 62 66 70 72 74 76 78 80 82 84 86 88 92 96 0.2 4 3 2 0 6 10 14 18 22 26 30 34 38 42 50 55 60 64 68 72 76 78 80 82 84 86 88 90 92 94 98 102 0.1 2 1 0 2 8 12 16 20 24 28 32 36 40 44 52 57 62 66 70 74 78 80 82 84 86 88 90 92 94 96 100 104 0.05 1 0 1 3 9 13 17 21 25 29 33 37 41 45 53 58 63 67 71 75 79 81 83 85 87 89 91 93 95 97 101 105 0.0 0 1 2 4 10 14 18 22 26 30 34 38 42 46 54 59 64 68 72 76 80 82 84 86 88 90 92 94 96 98 102 106 Ending Value (mA) Table 1 — Number of Backlight Fade Steps between Values (See Note) Applications Information (continued) NOTE: The fade time is determined by multiplying the number of steps by the fade rate (fade steps × fade rate = fade time).

When all LEDs are disabled, sleep mode is activated. This is a reduced current mode that helps minimize overall current consumption by disabling the clock and the charge pump while continuing to monitor the serial inter- face for commands. An additional current savings can be obtained by putting the serial interface in standby mode (see SemPulse Interface, Standby Mode). Protection Features The SC662 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 LED Float Detection Output Open Circuit Protection Over-Voltage Protection (OVP) at the OUT pin prevents the charge pump from producing an excessively high output voltage. In the event of an open circuit between the OUT pin and all current sinks (no loads connected), the charge pump runs in open loop and the voltage rises up to the OVP limit. OVP operation is hysteretic, meaning the charge pump will momentarily turn off until V OUT is sufficiently reduced. The maximum OVP threshold is 6.0V, allowing the use of a ceramic output capacitor rated at 6.3V. Over-Temperature Protection The OT (Over-Temperature) protection circuit prevents the device from overheating and experiencing a catastrophic failure. When the junction temperature exceeds 165°C, the device goes into thermal shutdown with all outputs dis - abled until the junction temperature is reduced. All register information is retained during thermal shutdown. Hysteresis of 20 °C is provided to ensure that the device cools sufficiently before re-enabling. Charge Pump Output Current Limit The device limits the charge pump current at the OUT pin. If the OUT pin is shorted to ground, or V OUT is lower than VUVLO, the typical output current limit is 60mA. The output current is limited to 300mA when over loaded resistively with VOUT greater than 2.4V.

• ••• LED Float Detection Float detect is a fault detection feature of the LED backlight outputs. If an output is programmed to be enabled and an open circuit fault occurs at any backlight output, that output will be disabled to prevent a sustained output OVP condition from occurring due to the resulting open loop. Float detect ensures device protection but does not ensure optimum performance. Unused LED outputs must be dis- abled to prevent an open circuit fault from occurring. Capacitor Selection The SC662 is designed to use low-ESR ceramic capaci- tors for the input and output decoupling capacitors as well as the charge pump bucket capacitors. The required value of input and output capacitors can vary with sup- ply and layout conditions, but typically 1µF 0402 (1005 metric) size X5R capacitors are sufficient for both CIN and COUT when 250kHz is selected for the charge pump clock. Typically 0.47µF 0402 size X5R capacitors are sufficient for CIN and COUT when the charge pump clock is1MHz. Table 1 — Recommended Capacitors Cap Value μF Case Size fPUMP kHz Notes CIN , COUT 1.0 0402 250 Recommended for FSEL = 0, Typical output VPP ≤ 40mV at 250kHz 0.47 0402 1000 Recommended for FSEL = 1, Typical output VPP ≤ 40mV at 1MHz C1 , C2 1.0 0402 250 Required to provide full rated output current and maintain a low 1.5x—2x mode transition point for optimum efficiency. 0.47 0402 1000 Required to provide full rated output current and maintain a low 1.5x—2x mode transition point for optimum efficiency. NOTE: Use only X5R type capacitors, with a 6.3V rating or higher Applications Information (continued)

PCB (Printed Circuit Board) layout directly effects the junc- tion to ambient thermal resistance ( θJA). Layout perfor - mance may place limits on the SC662 performance. The SC662 is capable of 150mA of total output current in an ambient temperature of up to 85°C. Both of these param- eters, maximum output current (I OUT(MAX) ), and maximum ambient temperature (T A), may be reduced if the layout does not provide for adequate heat dissipation. Layout guidelines are recommended in the next section, PCB Layout Considerations. Applications Information (continued)

SemPulse is a write-only single wire interface. It provides the capability to access up to 32 registers that control device functionality. Two sets of pulse trains are transmit- ted via the SPIF pin. The first pulse set is used to set the desired address. After the bus is held high for the address hold period, the next pulse set is used to write the data value. After the data pulses are transmitted, the bus is held high again for the data hold period to signify the data write is complete. At this point the device latches the data into the address that was selected by the first set of pulses. See the SemPulse Timing Diagrams for descriptions of all timing parameters. Chip Enable/Disable The device is enabled when the SemPulse interface pin (SPIF) is pulled high for greater than t SU. If the SPIF pin is pulled low again for more than t SD, the device will be disabled. Address Writes The first set of pulses can range between 0 and 31 (or 1 to 32 rising edges) to set the desired address. After the pulses are transmitted, the SPIF pin must be held high for tHOLDA to signal to the slave device that the address write is finished. If the pulse count is between 0 and 31 and the line is held high for t HOLDA, the address is latched as the destination for the next data write. If the SPIF pin is not held high for tHOLDA, the slave device will continue to count pulses. Note that if tHOLDA exceeds its maximum specifica- tion, the bus will reset. This means that the communication is ignored and the bus resumes monitoring the pin, expecting the next pulse set to be an address. If the total exceeds 31 pulses, SPIF must be held high until the bus reset time t BR is exceeded before commencing communication. Data Writes After the bus has been held high for the minimum address hold period, the next set of pulses are used to write the data value. The total number of pulses can range from 0 to 63 (or 1 to 64 rising edges) since there are a total of 6 register bits per register. Just like with the address write, the data write is only accepted if the bus is held high for tHOLDD when the pulse train is completed. If the proper hold time is not received, the interface will keep counting pulses until the hold time is detected. If the total exceeds 63 pulses, the write will be ignored and the bus will reset after the next valid hold time is detected. After the bus has been held high for tHOLDD, the bus will expect the next pulse set to be an address write. Note that this is the same effect as the bus reset that occurs when t HOLDA exceeds its maximum specification. For this reason, there is no maximum limit on t HOLDD — the bus simply waits for the next valid address to be transmitted. Multiple Writes It is important to note that this single-wire interface requires the address to be paired with its corresponding data. If it is desired to write multiple times to the same address, the address must always be re-transmitted prior to the corresponding data. If it is only transmitted one time and followed by multiple data transmissions, every other block of data will be treated like a new address. The result will be invalid data writes to incorrect addresses. Note that multiple writes only need to be separated by the minimum t HOLDD for the slave to interpret them cor - rectly. As long as tHOLDA between the address pulse set and the data pulse set is less than its maximum specification but greater than its minimum, multiple pairs of address and data pulse counts can be made with no detrimental effects. Standby Mode Once data transfer is completed, the SPIF line must be returned to the high state for at least 10ms to return to the standby mode. In this mode, the SPIF line remains idle while monitoring for the next command. This mode allows the device to minimize current consumption between commands. Once the device has returned to standby mode, the bus is automatically reset to expect the address pulses as the next data block. This safeguard is intended to reset the bus to a known state (waiting for the beginning of a write sequence) if the delay exceeds the reset threshold.

Address D5 D4 D3 D2 D1 D0 Reset Value Description 00h BLEN6 BLEN5 BLEN4 BLEN3 BLEN2 BLEN1 00h Backlight Enable 01h 0(2) MBL4 MBL3 MBL2 MBL1 MBL0 00h Main Backlight Current 02h 0(2) SBL4 SBL3 SBL2 SBL1 SBL0 00h Sub Backlight Current 03h 0(2) TBL4 TBL3 TBL2 TBL1 TBL0 00h Third Backlight Current 04h 0(2) 0(2) 0(2) 0(2) MFADE1 MFADE0 00h Main Fade 05h 0(2) 0(2) FSEL MB2 MB1 MB0 00h Frequency and Banking Configurations Registers and Bit Definitions BL Enable Control Register (00h) This register enables each individual LED. BLEN6 — BLEN1 [D5:D0] These active high bits enable the six backlight drivers. Each LED can be controlled independently. Notes: (1) All registers are write-only. (2) 0 = always write a 0 to these bits Register Map(1)

Register and Bit Definitions (continued) Main Backlight Current Control Register (01h) This register is used to set the currents for the backlight current sinks assigned to the Main Backlight Group. This group can also be used to control red LEDs for limited RGB control. These current sinks need to be enabled in the Backlight Enable Control register to be active. Bit D5 This bit is unused and is always a zero, so the maximum pulse count for this register is 31. MBL4 — MBL0 [D4:D0] These bits are used to set the current for the main back - light current sinks. All enabled main backlight current sinks will sink the same current, as shown in Table 2. Table 2 — Main Backlight Current Settings MBL4 MBL3 MBL2 MBL1 MBL0 Backlight Current (mA) 0 0 0 0 0 0 0 0 0 0 1 0.05 0 0 0 1 0 0.1 0 0 0 1 1 0.2 0 0 1 0 0 0.5 0 0 1 0 1 1.0 0 0 1 1 0 1.5 0 0 1 1 1 2.0 0 1 0 0 0 2.5 0 1 0 0 1 3.0 0 1 0 1 0 3.5 0 1 0 1 1 4.0 0 1 1 0 0 4.5 0 1 1 0 1 5.0 0 1 1 1 0 6.0 0 1 1 1 1 7.0 1 0 0 0 0 8.0 1 0 0 0 1 9.0 1 0 0 1 0 10 1 0 0 1 1 11 1 0 1 0 0 12 1 0 1 0 1 13 1 0 1 1 0 14 1 0 1 1 1 15 1 1 0 0 0 16 1 1 0 0 1 17 1 1 0 1 0 18 1 1 0 1 1 19 1 1 1 0 0 20 1 1 1 0 1 21 1 1 1 1 0 23 1 1 1 1 1 25

Register and Bit Definitions (continued) Sub Backlight Current Control Register (02h) This register is used to set the currents for the backlight current sinks assigned to the Sub Backlight Group. This group can also be used to control green LEDs for limited RGB control. These current sinks need to be enabled in the Backlight Enable Control register to be active. Bit D5 This bit is unused and is always a zero, so the maximum pulse count for this register is 31. SBL4 — SBL0 [D4:D0] These bits are used to set the current for the sub backlight current sinks. All enabled sub backlight current sinks will sink the same current, as shown in Table 3. Table 3 — Sub Backlight Current Settings SBL4 SBL3 SBL2 SBL1 SBL0 Backlight Current (mA) 0 0 0 0 0 0 0 0 0 0 1 0.05 0 0 0 1 0 0.1 0 0 0 1 1 0.2 0 0 1 0 0 0.5 0 0 1 0 1 1.0 0 0 1 1 0 1.5 0 0 1 1 1 2.0 0 1 0 0 0 2.5 0 1 0 0 1 3.0 0 1 0 1 0 3.5 0 1 0 1 1 4.0 0 1 1 0 0 4.5 0 1 1 0 1 5.0 0 1 1 1 0 6.0 0 1 1 1 1 7.0 1 0 0 0 0 8.0 1 0 0 0 1 9.0 1 0 0 1 0 10 1 0 0 1 1 11 1 0 1 0 0 12 1 0 1 0 1 13 1 0 1 1 0 14 1 0 1 1 1 15 1 1 0 0 0 16 1 1 0 0 1 17 1 1 0 1 0 18 1 1 0 1 1 19 1 1 1 0 0 20 1 1 1 0 1 21 1 1 1 1 0 23 1 1 1 1 1 25

Register and Bit Definitions (continued) Third Backlight Current Control Register (03h) This register is used to set the currents for the backlight current sinks assigned to the Third Backlight Group. This group can also be used to control blue LEDs for limited RGB control. These current sinks need to be enabled in the Backlight Enable Control register to be active. Bit D5 This bit is unused and is always a zero, so the maximum pulse count for this register is 31. TBL4 — TBL0 [D4:D0] These bits are used to set the current for the third back - light current sinks. All enabled third backlight current sinks will sink the same current, as shown in Table 4. Table 4 — Third Backlight Current Control Bits TBL4 TBL3 TBL2 TBL1 TBL0 Backlight Current (mA) 0 0 0 0 0 0 0 0 0 0 1 0.05 0 0 0 1 0 0.1 0 0 0 1 1 0.2 0 0 1 0 0 0.5 0 0 1 0 1 1.0 0 0 1 1 0 1.5 0 0 1 1 1 2.0 0 1 0 0 0 2.5 0 1 0 0 1 3.0 0 1 0 1 0 3.5 0 1 0 1 1 4.0 0 1 1 0 0 4.5 0 1 1 0 1 5.0 0 1 1 1 0 6.0 0 1 1 1 1 7.0 1 0 0 0 0 8.0 1 0 0 0 1 9.0 1 0 0 1 0 10 1 0 0 1 1 11 1 0 1 0 0 12 1 0 1 0 1 13 1 0 1 1 0 14 1 0 1 1 1 15 1 1 0 0 0 16 1 1 0 0 1 17 1 1 0 1 0 18 1 1 0 1 1 19 1 1 1 0 0 20 1 1 1 0 1 21 1 1 1 1 0 23 1 1 1 1 1 25

Main Fade Control (04h) This register sets the fade status and rate for the main backlight group. Bits [D5:D2] These bits are unused and are always zeros, so the maximum pulse count for this register is 3. MFADE1, MFADE0[D1:D0] These bits are used to enable fade and set the fade rate between two backlight currents as shown in Table 5. Table 5 — Main Display Fade Control Bits MFADE1 MFADE0 Fade Feature RiseFall Rate (msstep) 0 0 OFF 0 1 2 1 0 4 1 1 6 When the fade rate is set to 2, 4, or 6ms and then a new backlight current is set, the backlight current will change from its current value to the new value in steps, pausing at each step for the duration of the fade rate before proceed- ing to the next step. The exact length of time used to fade between any two backlight values is determined by multi- plying the fade rate by the number of steps between the old and new backlight values. The fade time can be calculated from the data provided in Table 1 on page 15. Backlight Grouping Configuration (05h) This register assigns the LEDs to the backlight bank configurations. Bits [D5:D4] These bits are unused and are always zeros, so the maximum pulse count for this register is 16. FSEL [D3] This bit sets the charge pump clock frequency. FSEL = 0 for 250kHz, and FSEL = 1 for 1MHz. The default state for this bit is zero. MB2 and MB0 [D2:D0] These bits are used to set the number of LED drivers dedi- cated to each backlight group. This allows the device to drive up to three different sets of LEDs with different current settings. Note that any driver assigned to any LED group can still be disabled independently if not needed. The code set by these bits determines how the LED drivers are assigned among the three LED groups according to the assignments listed in Table 6. Default state for each of these three bits is zero (all LEDs assigned to main display). Table 6 — Backlight Grouping Configuration MB2 MB1 MB0 Main Display LED Drivers Sub Display LED Drivers Third Display LED Drivers 0 0 0 BL1-BL6 0 0 1 BL1-BL3 BL4-BL6 0 1 0 BL1-BL2 BL3-BL4 BL5-BL6 0 1 1 BL1-BL2, BL5-BL6 BL3 BL4 1 0 0 BL1-BL3 BL4-BL5 BL6 1 0 1 BL1-BL4 BL5-BL6 1 1 X BL1-BL5 BL6 Register and Bit Definitions (continued)

Outline Drawing — MLPQ-UT-14 2x2 CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).1. PIN 1 INDICATOR (LASER MARK) A B aaa C C SEATING PLANE bbb C A B N D E A DIMENSIONS A N aaa bbb L e D E b DIM - 0.600.50

0.40 BSC

(0.152) 0.30 0.10 0.08 0.35 0.15 1.90 0.00 0.20 2.00 0.40 0.25 2.10 0.05 NOM MILLIMETERS MIN MAX 1.90 2.00 2.10 D1 0.65 0.80 0.90 E1 0.65 0.80 0.90 0.34 0.68 NOTES: 2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. bxN e D/2 E/2 LxN

P Z X Y C G DIM MILLIMETERS FAILURE TO DO SO MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE. SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD3. H 0.80 K 0.80 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 4. SQUARE PACKAGE - DIMENSIONS APPLY IN BOTH " X " AND " Y " DIRECTIONS. PX K H 0.65 2.60 (1.95) 1.30 0.20 0.40 THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. NOTES: 0.34 0.68(C) G Y Z Land Pattern — MLPQ-UT-14 2x2

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