Semtech expands buck converter platform 3.5-MHz, 500-mA synchronous step-down regulator

Semtech Corp., has introduced a highly integrated 500 mA synchronous step-down (buck) regulator with the tiny size and output flexibility needed for low voltage point-of-load regulation, as well as mobile device applications.

The 1.5 x 1.5 mm (0.6 mm max. height) SC195 operates from inputs of 2.9 V to 5.5 V and provides 15 pin-programmable output voltages from 0.8 V to 3.3 V, covering all the typical core and I/O voltage rails with one device. The 3.5 MHz PWM operation balances high efficiency (up to 94 percent) and fast transient response with small external components. Automatic PSAVE operation reduces quiescent current to 38 uA typical at light loads. The SC195 includes a 0.1 uA typical shutdown mode.

To set the output voltage, the SC195 utilizes four digital programming pins to eliminate external feedback components, thereby saving space, increasing reliability and eliminating the inventory overhead of stocking individual fixed output voltage regulators for each different load. In applications such as graphics or other processors where voltage levels change on the fly, the programming pins can be driven from the host controller to dynamically position the output voltage level.

With the SC195's fully-integrated feedback network and internal loop compensation, a complete solution requires only three external components: two small ceramic input/output capacitors and a 1 uH inductor. Due to the 3.5 MHz switching frequency, multi-layer shielded inductors are very suitable, making it possible to build the complete solution in less than 15 mm PCB footprint with a thin sub-millimeter profile.

For increased system reliability, the SC195 has built-in soft-start, over-voltage protection, over-temperature protection, foldback current limit, short-circuit protection, under-voltage lockout and floating programming pin protection. Fast transient response protects sensitive downstream ICs from excessive supply voltage variations. 100 percent duty-cycle operation is also supported for applications with low headroom between input and output.

The SC195 is available in 1.5 mm x 1.5 mm lead-free 8-pin MLPQ-UT package, is halogen-free and complies 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 SC195

  • Input voltage range: 2.9 V to 5.5 V
  • Output current rating: 500 mA continuous
  • Pin-programmable output voltage: 15 steps from 0.8 V to 3.3 V
  • Dynamic output voltage scaling

  • Only three small external components; <15 mm total system solution
  • 3.5 MHz PWM operation with automatic PSAVE at light loads
  • 38 uA quiescent current; 0.1uA shutdown current
  • Extensive protection features: soft-start, over-voltage, over-temperature, foldback current limit, short-circuit, under-voltage lockout, floating programming pin detection

  • Ultra-thin MLPQ package: 1.5 x 1.5 x 0.6 mm

Availability and Pricing

The SC195 is priced at $0.69 each in 3,000-piece lots and is available immediately in production quantities. An evaluation board (SC195EVB) is also available. Semtech offers comprehensive design assistance, including field- and factory-based support.

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