Overview
The LM3670MF-3.3, produced by National Semiconductor (now part of Texas Instruments), is a miniature step-down DC-DC converter designed for powering ultralow voltage circuits. This device is optimized for use in portable devices such as mobile phones, handheld devices, PDAs, and battery-powered instruments. It operates from a single Li-Ion cell or three-cell NiMH/NiCd batteries, providing a fixed output voltage of 3.3V with high efficiency and low quiescent current.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Input Voltage Range | 2.5 V to 5.5 V | V |
| Output Voltage | 3.3 V (Fixed) | V |
| Maximum Load Current | 350 mA | mA |
| Typical Quiescent Current | 15 µA | µA |
| Switching Frequency (PWM Mode) | 1 MHz (Typical) | Hz |
| Efficiency | Up to 95% (Typical at loads between 1 mA and 100 mA) | % |
| Shutdown Current | 0.1 µA (Typical) | µA |
| Package Type | SOT-23 (5-pin) | - |
Key Features
- High efficiency with internal synchronous rectification (up to 95% efficiency)
- Automatic switching between PWM and PFM modes for improved system control and battery life
- Low dropout operation with 100% duty cycle mode
- Internal soft start to limit in-rush current during start-up
- Current overload protection and thermal overload protection
- Only three external surface-mount components required (one inductor, two ceramic capacitors)
- Low quiescent current in shutdown mode (0.1 µA typical)
Applications
- Mobile phones and handheld devices
- PDAs and palm-top PCs
- Portable instruments and battery-powered devices
Q & A
- What is the input voltage range of the LM3670MF-3.3?
The input voltage range is from 2.5 V to 5.5 V.
- What is the fixed output voltage of the LM3670MF-3.3?
The fixed output voltage is 3.3 V.
- What is the maximum load current capability of the LM3670MF-3.3?
The maximum load current capability is 350 mA.
- What is the typical quiescent current of the LM3670MF-3.3?
The typical quiescent current is 15 µA.
- What is the switching frequency in PWM mode for the LM3670MF-3.3?
The switching frequency in PWM mode is typically 1 MHz.
- How efficient is the LM3670MF-3.3?
The efficiency can be up to 95% at loads between 1 mA and 100 mA.
- What is the shutdown current of the LM3670MF-3.3?
The shutdown current is typically 0.1 µA.
- What package type is the LM3670MF-3.3 available in?
The LM3670MF-3.3 is available in a 5-pin SOT-23 package.
- What are the key features of the LM3670MF-3.3?
Key features include high efficiency, automatic PWM and PFM mode switching, low dropout operation, internal soft start, and current overload protection.
- What are typical applications for the LM3670MF-3.3?
Typical applications include mobile phones, handheld devices, PDAs, palm-top PCs, and other portable instruments.
