National Semiconductor LM3671 Manuals

The LM3671 is a 2MHz, 600mA step-down DC-DC converter optimized for powering ultra-low voltage circuits from a single Li-Ion cell or 3 cell NiMH/NiCd batteries. It provides up to 600mA load current over an input voltage range from 2.8V to 5.5V. There are several different fixed voltage output options available as well as an adjustable output voltage version. The device offers superior features and performance for mobile phones and similar portable applications with complex power management systems. Automatic intelligent switching between PWM low-noise and PFM low-current mode offers improved system control. During full-power operation, a fixed-frequency 2 MHz (typ) PWM mode drives loads from ∼70 mA to 600 mA max. Hysteretic PFM mode extends the battery life through reduction of the quiescent current to 16 µA (typ) at 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 consumption to 0.01 µA (typ). The LM3671 is available in a SOT23-5 package with Pb and No Pb (Lead free) versions. A high switching frequency - 2 MHz (typ) - allows use of tiny surface-mount components. Only three external surface-mount components, an inductor and two ceramic capacitors, are required.

This document introduces the features and characteristics of LM3671 step-down DC-DC converter. LM3671 step-down DC-DC converter is designed for power supply low voltage circuits from a single Li-Ion cell battery and input voltage rails from 2.7V to 5.5V. The chip provides up to 600mA load current, over the entire input voltage range. There are several different fixed voltage output options available as well as an adjustable output voltage version. The device offers superior features and performance for mobile phones and similar portable systems. Automatic in- telligent switching between PWM low-noise and PFM low- current mode offers improved system control. During PWM mode, the device operates at a fixed-frequency of 2 MHz (typ). Hysteretic PFM mode extends the battery life by re- ducing the quiescent current to 16 µA (typ) during light load and standby operation. Internal synchronous rectification provides high efficiency during PWM mode operation. In shutdown mode, the device turns off and reduces battery consumption to 0.01 µA (typ). The LM3671 is available in SOT23-5 and a tiny 5-bump micro SMD packages in leaded (PB) and lead-free (NO PB) versions. A high switching frequency of 2 MHz (typ) allows use of tiny surface-mount components. Only three external surface-mount components, an inductor and two ceramic capacitors, are required.

The LM3671 is a 2MHz, 600mA step-down DC-DC converter from TI. It is optimized for powering low voltage circuits from a single Li-Ion cell battery and input voltage rails from 2.7V to 5.5V. It provides up to 600mA load current, over the entire input voltage range. There are several different fixed voltage output options avail- able as well as an adjustable output voltage version range from 1.1V to 3.3V. The device offers superior features and performance for mo- bile phones and similar portable systems. Automatic intelli- gent switching between PWM low-noise and PFM low-current mode offers improved system control. During PWM mode, the device operates at a fixed-frequency of 2 MHz (typ.). Hys- teretic PFM mode extends the battery life by reducing the quiescent current to 16 µA (typ.) during light load and standby operation. Internal synchronous rectification provides high ef- ficiency during PWM mode operation. In shutdown mode, the device turns off and reduces battery consumption to 0.01 µA (typ.). The LM3671 is available in SOT23-5, tiny 5-bump micro SMD and a 6-pin LLP packages in leaded (PB) and lead-free (NO PB) versions. A high switching frequency of 2 MHz (typ.) al- lows use of tiny surface-mount components. Only three ex- ternal surface-mount components, an inductor and two ceramic capacitors, are required.