0.9V boot high efficiency synchronous step-up converter

ELM624BA provides power-supply solutions for products powered by either one, two or three-cell Alkaline, NiMH, or one-cell Li-Ion or Li-polymer battery. Its available output current depends on the input-to-output voltage ratio. ELM624BA works based on current–mode pulse-width-modulation (PWM) control using synchronous rectification to obtain maximum efficiency with the minimum quiescent current. The output voltage is programmed using an external resistor divider. ELM624BA circuit is switched off to minimize battery consumption during the shutdown mode and connects the VIN pin to the VOUT pin allowing the input battery to be used for backup systems like a real-time clock supply and SRAM data hold when the converter is off. ELM624BA is offered in a small 6-pin SOT-26 package.

VOUT pulled to VIN in shutdown mode
Input under-voltage lockout
Switching frequency800kHz (4.7µH)
Adjustable output voltage2.5V to 5.5V
High efficiency92%
Quiescent current12µA
Startup input voltage/load0.9V/10mA, 0.7V/1mA
Operating input voltage0.9V to 5V
Switch current450mA max.
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Battery powered applications :
- 1 to 3 Cell Alkaline, NiCd or NiMH
- 1 cell Li-lon
Solar or fuel cell powered applications
Consumer and portable medical products
Personal electronics goods

Absolute Maximum Ratings

Supply voltageVin-0.3 to +6.0V
Output voltageVout-0.3 to +6.0V
The other pinsVother-0.3 to +6.0V
Dynamic Vsw in 10ns durationVsw-2.0 to Vout+2.0V
Junction temperatureTj+150°C
Lead temperature(Soldering 10s)260°C
Thermal resistanceθja125°C/W
Thermal resistanceθjc66°C/W
Power dissipationPd0.8W
Storage temperature rangeTstg-55 to +150°C

Block diagram