LM3671MF-ADJ/NOPB

The LM3671 step-down DC-DC converter is optimized for ultra-low voltage circuits powered by single-cell Li-Ion or three-cell NiMH/NiCd batteries. It delivers up to 600mA of load current over an input voltage range of 2.8V to 5.5V. Multiple fixed voltage output options and an adjustable output voltage version are available. Superior features and performance are provided for mobile phones and similar portable applications with complex power management systems. Automatic intelligent switching between PWM low-noise mode and PFM low-current mode delivers improved system control. During full-power operation, fixed-frequency 2MHz (typical) PWM mode drives loads from approximately 70mA up to a maximum of 600mA. Hysteretic PFM mode extends battery life by reducing quiescent current to 16μA (typical) during light loads and system standby. Internal synchronous rectification provides high efficiency. In shutdown mode (enable pin pulled low), the device turns off and reduces battery drain to 0.01μA (typical). The LM3671 is available in a SOT23-5 package in both leaded and lead-free versions. The high switching frequency — 2MHz (typical) — allows the use of miniature SMT components. Only three external SMT components are required: one inductor and two ceramic capacitors.

Key features

• Automatic PFM/PWM mode switching
• Fixed output voltage and adjustable versions available
• SOT23-5 package
• Internal synchronous rectification for high efficiency
• Internal soft-start
• Typical shutdown current 0.01 μA
• Single Li-ion or three NiMH/NiCd cell supply
• Only three small SMT external components required (one inductor, two ceramic capacitors)
• Overcurrent and thermal shutdown protection
• Typical quiescent current 16 μA
• Maximum load capability 600 mA