Overview
The LM3243TMX/NOPB is a high-efficiency step-down DC-DC converter designed by Texas Instruments. It is optimized for powering multi-mode 2G, 3G, and 4G RF power amplifiers (PAs) from a single Lithium-Ion cell. The converter operates within an input voltage range of 2.7 V to 5.5 V and can dynamically adjust the output voltage from 0.4 V to 3.6 V. This flexibility ensures efficient operation across various power levels of the RF PA.
The LM3243 features both Pulse Width Modulation (PWM) and Pulse Frequency Modulation (PFM) modes, allowing for high efficiency and low output voltage ripple. It also includes an analog bypass function with low dropout resistance, current and thermal overload protection, and a unique Active Current Assist and Analog Bypass (ACB) feature to minimize inductor size.
Key Specifications
| Specification | Value |
|---|---|
| Input Voltage Range | 2.7 V to 5.5 V |
| Output Voltage Range | 0.4 V to 3.6 V (Typical) |
| Maximum Load Current (PWM Mode) | 2.5 A |
| PWM Switching Frequency | 2.7 MHz (Average) |
| Operating Temperature Range | -30°C to 90°C |
| Package Type | DSBGA (YFQ) - 16 Pins |
| Dropout Resistance (Typical) | 45 mΩ |
| Maximum Peak Inductor Current | 1.9 A (Typical), 2.1 A (Maximum) |
Key Features
- High-Efficiency PFM and PWM Modes with Internal Synchronous Rectification
- Analog Bypass Function with Low Dropout Resistance (45 mΩ Typical)
- Dynamically Adjustable Output Voltage: 0.4 V to 3.6 V (Typical) in PFM and PWM Modes
- Maximum Load Current: 2.5 A in PWM Mode
- PWM Switching Frequency: 2.7 MHz (Average)
- Modulated Switching Frequency to Aid Rx Band Compliance
- Operates From a Single Li-ion Cell (2.7 V to 5.5 V)
- Current and Thermal Overload Protection
- Active Current Assist and Analog Bypass (ACB) to Minimize Inductor Size
Applications
The LM3243 is specifically designed for powering RF power amplifiers in various communication devices, including:
- Cell phones
- Portable communication devices
- Battery-powered RF devices
It is particularly useful in applications requiring high efficiency, low output voltage ripple, and dynamic output voltage adjustment to ensure optimal performance across different power levels.
Q & A
- What is the input voltage range of the LM3243?
The input voltage range of the LM3243 is 2.7 V to 5.5 V.
- What is the dynamically adjustable output voltage range of the LM3243?
The output voltage range is 0.4 V to 3.6 V (Typical) in both PFM and PWM modes.
- What is the maximum load current in PWM mode?
The maximum load current in PWM mode is 2.5 A.
- What is the PWM switching frequency of the LM3243?
The PWM switching frequency is 2.7 MHz (Average).
- What is the operating temperature range of the LM3243?
The operating temperature range is -30°C to 90°C.
- What package type is the LM3243 available in?
The LM3243 is available in a DSBGA (YFQ) package with 16 pins.
- What is the dropout resistance of the LM3243?
The dropout resistance is 45 mΩ (Typical).
- Does the LM3243 have current and thermal overload protection?
Yes, the LM3243 includes current and thermal overload protection.
- What is the Active Current Assist and Analog Bypass (ACB) feature?
The ACB feature minimizes inductor size by providing a parallel current path and limiting the maximum inductor current.
- In which applications is the LM3243 typically used?
The LM3243 is typically used in cell phones, portable communication devices, and battery-powered RF devices.
