Date: 22/07/2010

Boost type tiny DC/DC converters from Semtech

Semtech has released the SC12x devices, a boost converter platform, which Semtech claims has the world's smallest step-up regulators for low-voltage applications. The SC120, SC121 and SC122 boost inputs from as low as 0.7V to a regulated output settable from 1.8V to 5.0V and are available in tiny 1.5x2mm ultra-thin (0.6mm max.) plastic packages. These devices are suitable for portable applications powered by alkaline, NiMH, or 1-cell Li-ion batteries, or as point-of-load regulators in non-portable applications where a low voltage needs to be boosted to a higher voltage rail for localized use.

"The new SC120 platform sets the benchmark for its sophisticated features, performance, and ease of use within a tiny, thin, reliable, and green footprint." said Scott Brown, Semtech Vice President of Marketing for Power Management Products.

The SC120 include 1.2MHz low-noise PWM operation, an internal low-on-resistance switch and synchronous rectifier for up to 94% efficiency, automatic PSAVE mode for light-load efficiency, an anti-ringing circuit that dampens stray oscillations on the inductor terminal, ±1.5% initial accuracy, internal/external feedback modes, soft-start, thermal and current limit protection, and a 0.1µA real shutdown mode that reverses the rectifier's body-diode and actively discharges the output fully to ground.

For noise sensitive applications, the SC121 eliminates the PSAVE mode in favor of forced-PWM operation at all loads. And for specialized keep-alive applications, the SC122 utilizes PSAVE mode only and allows the output voltage to float high during shutdown by eliminating active discharge. The SC122 also limits the input to no more than 1.6V and the output to a fixed 3.3V.

The SC12x devices utilize internal loop compensation and internal soft-start to minimize external components. Grounding the feedback pin enables internally fixed 3.3V regulation mode, which requires three small external components i.e. two ceramic capacitors and an inductor. For setting other output voltages from 1.8V to 5.0V via external feedback, two small resistors and a small feed-forward capacitor are added.

Applications

1. MP3 Player: External Memory Interface, Jack (SPKR), Touchpad/User Input Device, Memory, Support Function IC.
2. Cable Modem: Companion Function Chip.
3. Cell Phone: Bluetooth, LCD Bias, External Memory, Speaker Driver, WiFi 802.11x.
4. Digital Camera: External Memory, Support Function IC, Video Interface.
5. DSL Modem: WI-FI 802.11X.
6. Notebook: Peripheral Power.
7. Set Top Box: Boost Regulators/Controllers.

Packages: 1.5x2mm ultra-thin MLPD (all) or SOT23 (SC120 only)

Price:
The SC120, SC121, and SC122 in MLPD-UT package are priced at each US$0.80 for 3,000-piece lots.
The SC120 in SOT23 package is priced at each US$0.71 for 3,000-piece lots.

Availability: Now

For more information visit: www.semtech.com.