The LM3679 step-down DC-DC converter is optimized for powering ultra-low voltage circuits from a single Li-Ion cell battery and input voltage rails from 2.5V to 5.5V. It provides up to 350mA load current, over the entire input voltage range. The LM3679 output voltage can be configured to 1.2V, 1.5V, or 1.8V.

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 PWM mode operation, the device operates at a fixed-frequency of 3 MHz (typ). PWM mode drives loads from ~ 80mA to 350mA max. Hysteretic 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 efficiency. In shutdown mode (Enable pin pulled low), the device turns off and reduces battery consumption to 0.01 µA (typ).

The LM3679 is available in a lead-free (No PB) 5-bump micro SMD package, 0.6mm height, and in an ultra thin 0.3mm height UR package. Using the UR package along with specific external components, allows for a low profile solution size with a max height of 0.55mm. A switching frequency of 3 MHz (typ) allows use of tiny surface-mount components. Only three external surface-mount components, an inductor and two ceramic capacitors, are required. .

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16 μA typical quiescent current

350 mA maximum load capability

3 MHz PWM fixed switching frequency (typ)

Automatic PFM/PWM mode switching

Available in 5-bump micro SMD package and UR package

Internal synchronous rectification for high efficiency

Internal soft start

0.01 μA typical shutdown current

Operates from a single Li-Ion cell battery

Current overload and Thermal shutdown protection

Three external components required for typical applications

Low profile solution (0.55mm max height, includes four external components)

• Vin (Min) (V)
• 2.5
• Vin (Max) (V)
• 5.5
• Vout (Min) (V)
• 1.8
• Vout (Max) (V)
• 1.8
• Iout (Max) (A)
• 0.35
• Iq (Typ) (uA)
• 16
• Switching frequency (Min) (kHz)
• 2500
• Switching frequency (Max) (kHz)
• 3500
• Features
• Enable, Light Load Efficiency, Synchronous Rectification
• Rating
• Catalog
• Regulated outputs (#)
• 1
• Control mode
• Voltage Mode
• Duty cycle (Max) (%)
• 100

LM3679的完整型号有：LM3679UR-1.2/NOPB、LM3679UR-1.8/NOPB、LM3679URX-1.2/NOPB、LM3679URX-1.8/NOPB，以下是这些产品的关键参数及官网采购报价：

LM3679UR-1.2/NOPB，工作温度：PropertyValue，封装：DSBGA (YPD)-5，包装数量MPQ：250个，MSL 等级/回流焊峰值温度：Level-1-260C-UNLIM，引脚镀层/焊球材料：SNAGCU，TI官网LM3679UR-1.2/NOPB的批量USD价格：.452（1000+）

LM3679UR-1.8/NOPB，工作温度：-30 to 85，封装：DSBGA (YPD)-5，包装数量MPQ：250个，MSL 等级/回流焊峰值温度：Level-1-260C-UNLIM，引脚镀层/焊球材料：SNAGCU，TI官网LM3679UR-1.8/NOPB的批量USD价格：.452（1000+）

LM3679URX-1.2/NOPB，工作温度：PropertyValue，封装：DSBGA (YPD)-5，包装数量MPQ：3000个，MSL 等级/回流焊峰值温度：Level-1-260C-UNLIM，引脚镀层/焊球材料：SNAGCU，TI官网LM3679URX-1.2/NOPB的批量USD价格：.377（1000+）

LM3679URX-1.8/NOPB，工作温度：-30 to 85，封装：DSBGA (YPD)-5，包装数量MPQ：3000个，MSL 等级/回流焊峰值温度：Level-1-260C-UNLIM，引脚镀层/焊球材料：SNAGCU，TI官网LM3679URX-1.8/NOPB的批量USD价格：.377（1000+）

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