Overview
The LM2733XMFX from Texas Instruments is a high-frequency switching boost converter IC designed for applications requiring high power density and efficiency. This device operates in current-mode control, offering fixed switching frequencies of either 1.6 MHz (X option) or 600 kHz (Y option). The LM2733 features a 40-V internal DMOS FET switch, enabling it to handle high output voltages and switch currents up to 1 A. The IC is packaged in a compact 5-pin SOT-23 package, making it ideal for space-constrained designs. It includes cycle-by-cycle current limiting and thermal shutdown for enhanced protection and reliability.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Input Voltage | 2.7 | - | 14 | V |
| Output Voltage | 3 | - | 40 | V |
| Switching Frequency (X Option) | 1.15 | 1.6 | 1.85 | MHz |
| Switching Frequency (Y Option) | 0.40 | 0.6 | 0.8 | MHz |
| Maximum Duty Cycle (X Option) | 87% | - | 93% | % |
| Maximum Duty Cycle (Y Option) | 93% | - | 96% | % |
| Switch Current | - | - | 1 A | A |
| Shutdown Current | - | - | < 1 µA | µA |
| Package Type | - | - | SOT-23 (5-pin) | - |
Key Features
- 40-V internal DMOS FET switch for high output voltages
- Fixed switching frequencies: 1.6 MHz (X option) and 600 kHz (Y option)
- Low RDS(ON) DMOS FET for high efficiency
- Switch current up to 1 A
- Wide input voltage range: 2.7 V to 14 V
- Low shutdown current (< 1 µA) for extended battery life
- Compact 5-pin SOT-23 package for high power density
- Cycle-by-cycle current limiting and thermal shutdown for protection
- Internal compensation simplifies design and reduces component count
- Logic-level shutdown pin for easy control
Applications
- White LED current source
- PDAs and palm-top computers
- Digital cameras
- Portable phones and games
- Local boost regulator in various portable electronics
Q & A
- What are the switching frequencies of the LM2733?
The LM2733 has two switching frequency options: 1.6 MHz (X option) and 600 kHz (Y option).
- What is the maximum switch current of the LM2733?
The maximum switch current of the LM2733 is up to 1 A.
- What is the input voltage range of the LM2733?
The input voltage range of the LM2733 is from 2.7 V to 14 V.
- What type of package does the LM2733 come in?
The LM2733 comes in a 5-pin SOT-23 package.
- What protection features does the LM2733 have?
The LM2733 features cycle-by-cycle current limiting and thermal shutdown for protection.
- How does the shutdown pin function on the LM2733?
The device is turned off by pulling the shutdown pin low. If not used, the pin should be tied directly to VIN. A pull-up resistor (50 k to 100 kΩ) to VIN is recommended if the SHDN function is needed.
- What types of capacitors are recommended for use with the LM2733?
Multilayer ceramic capacitors with X5R and X7R dielectric types are recommended due to their low ESR and high resonance frequency.
- What are some typical applications of the LM2733?
Typical applications include white LED current sources, PDAs, digital cameras, portable phones, and games.
- How does the internal compensation of the LM2733 simplify design?
The internal compensation of the LM2733 simplifies design by reducing the component count and making the feedback loop easier to implement.
- What is the significance of the high power density of the LM2733?
The high power density of the LM2733, achieved through the use of a minimal power loss internal switch and small inductors and capacitors, makes it ideal for space-constrained designs.
