Semtech Corp. has unveiled the SC654, SC657 and SC658 LED backlight charge pump drivers for 6, 5, and 4 LEDs, respectively.
Optimized for single-cell Li-ion battery applications, each part in this new platform is packaged in ultra-thin (0.6 mm max.) 14-pin 2x2 mm MLPQ package to provide the industry's smallest solution in reliable and easy-to-handle plastic packaging.
Each member of the SC65x family integrates a high-efficiency charge pump, multiple low-dropout current sink regulators, and the proprietary one-wire SemPulse interface. The mAhXLife charge pump monitors each LED's forward voltage and automatically selects between 1x, 1.5x and 2x modes to optimize efficiency as the battery voltage changes over time. The low-dropout current sink regulators provide LED current matching of 0.5 percent typical to ensure accurate and even illumination. LED current may be adjusted from 0 mA to 25 mA in 29 settings via the one-wire SemPulse interface. In addition, the SemPulse interface controls many other functions, including chip enable/shutdown, individual on/off for each current sink, up to three zones of lighting with individual current settings for each bank of LEDs, and three optional fade-in/out rates for elegant transitions when changing current settings.
In several modern handheld systems, the usual IC serial bus is becoming over-burdened with too many slave ICs. In such cases, the SemPulse interface is highly preferred because it provides a simple means of programming many features while consuming only one GPIO on the baseband or applications/graphics processor. The interface is simple, robust, and very tolerant of sloppy timing caused by interrupts elsewhere in the system. Semtech's applications team provides full design-in support with sample code and pre-written drivers to minimize the customer's software development efforts.
"The SC654, SC657, and SC658 are perfectly optimized to power backlights in next-generation mobile handheld applications where size is the key factor," said Karl Volk, Semtech Director of Marketing for Handheld Power.
The SC654, SC657, and SC658 are available in 2x2 mm lead-free 14-pin MLPQ-UT package, are halogen-free, and comply with the European Union's Restriction on Hazardous Substances in Electrical and Electronic Equipment (RoHS) directive to meet worldwide environmental and regulatory requirements.
Key features of the SC654, SC657, and SC658
- Input supply voltage range - 2.9 V to 5.5 V
- Charge pump modes - 1x, 1.5x and 2x
- Six (SC654), five (SC657) or four (SC658) adjustable current sinks
- One-wire SemPulse interface
- 29 current settings from 0 to 25 mA
- Current accuracy ±1.5 percent typical
- Current matching ±0.5 percent typical
- Individual on/off control for each LED
- Up to three zones/banks of LED current settings
- Optional fade-in/out with three programmable rates
- Ultra-thin MLPQ package - 2 x 2 x 0.6 mm
Availability and Pricing
The SC654 is priced at $0.60 each in 3,000-piece lots. The SC657 is priced at $0.55 each in 3,000-piece lots. The SC658 is priced at $0.51 each in 3,000-piece lots. Each device is available immediately in production quantities. Evaluation boards (SC654EVB, SC657EVB, and SC658EVB) are also available.
Datasheets:
SC654
SC657
SC658
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