Overview
The LM2733YMF from Texas Instruments is a high-frequency switching boost converter integrated circuit. It operates at fixed frequencies of either 1.6 MHz or 600 kHz, depending on the version. This device is designed for applications requiring high output voltages and features a 40-V internal DMOS FET switch, enabling switch currents up to 1 A. The LM2733 is packaged in a compact 5-pin SOT-23 package, making it ideal for space-constrained designs. It incorporates cycle-by-cycle current limiting and thermal shutdown for protection, and its internal compensation simplifies the design process by reducing the component count.
Key Specifications
| Parameter | Min | Max | Unit | |
|---|---|---|---|---|
| Switching Frequency (X Option) | 1.15 MHz | 1.6 MHz | 1.85 MHz | |
| Switching Frequency (Y Option) | 0.40 MHz | 0.60 MHz | 0.80 MHz | |
| Maximum Duty Cycle (X Option) | 87% | 93% | ||
| Maximum Duty Cycle (Y Option) | 93% | 96% | ||
| Input Voltage Range | 2.7 V | 14 V | ||
| Switch Current | 1 A | |||
| Shutdown Current | < 1 µA | |||
| Package | SOT-23 (5-pin) | |||
| Operating Temperature Range | -40°C | 125°C |
Key Features
- 40-V internal DMOS FET switch
- High switching frequencies: 1.6 MHz (X option) and 600 kHz (Y option)
- Low RDS(ON) DMOS FET
- Switch current up to 1 A
- Wide input voltage range: 2.7 V to 14 V
- Low shutdown current (< 1 µA)
- Compact 5-pin SOT-23 package
- Uses tiny capacitors and inductors
- Cycle-by-cycle current limiting and thermal shutdown for protection
- Internally compensated
Applications
- White LED current source
- PDAs and palm-top computers
- Digital cameras
- Portable phones and games
- Local boost regulator
Q & A
- What are the switching frequencies of the LM2733YMF? The LM2733YMF operates at either 1.6 MHz (X option) or 600 kHz (Y option).
- What is the maximum switch current of the LM2733YMF? The maximum switch current is up to 1 A.
- What is the input voltage range of the LM2733YMF? The input voltage range is from 2.7 V to 14 V.
- What type of package does the LM2733YMF come in? The LM2733YMF is packaged in a 5-pin SOT-23 package.
- What protection features does the LM2733YMF have? The device features cycle-by-cycle current limiting and thermal shutdown for protection.
- What is the typical shutdown current of the LM2733YMF? The typical shutdown current is less than 1 µA.
- What are some common applications of the LM2733YMF? Common applications include white LED current sources, PDAs, digital cameras, portable phones, and local boost regulators.
- How does the LM2733YMF handle thermal issues? The device's thermal performance is managed through its thermal shutdown feature and by calculating power dissipation within the FET switch.
- What type of capacitors are recommended for use with the LM2733YMF? Multi-layer ceramic capacitors with X5R and X7R dielectric types are recommended.
- How does the shutdown pin function on the LM2733YMF? The device is turned off by pulling the shutdown pin low. If not used, it should be tied directly to VIN with a pull-up resistor.
