Overview
The LMX2352TM/NOPB is a dual low-power frequency synthesizer from Texas Instruments, part of the PLLatinum family. This device is designed for use in local oscillator subsystems for radio transceivers. It is fabricated using National’s 0.5µ ABiC V silicon BiCMOS process. The LMX2352 is capable of generating stable, low-noise control signals for UHF and VHF voltage-controlled oscillators (VCOs) using a fractional N phase-locked loop technique.
Key Specifications
| Parameter | Min | Typ | Max | Units |
|---|---|---|---|---|
| Power Supply Voltage (Vcc RF/IF) | 2.7 | 5.5 | V | |
| Operating Temperature (TA) | -40 | 85 | °C | |
| Power Supply Current (Icc) at 3.0V | 4.75 | 6.0 | mA | |
| Power Down Current (Icc-PWDN) at 3.0V | 5 | 20 | µA | |
| RF Operating Frequency | 0.25 | 1.2 | GHz | |
| IF Operating Frequency | 10 | 550 | MHz | |
| Oscillator Frequency | 2 | 50 | MHz | |
| Phase Detector Frequency | 10 | MHz |
Key Features
- Operates from 2.7 V to 5.5 V supply voltage
- Low current consumption: typically 4.75 mA at 3.0 V
- Programmable or logical power down mode with low power down current (5 µA to 20 µA)
- Modulo 15 or 16 fractional RF N divider with various prescale ratios (8/9 or 16/17)
- Programmable charge pump current levels: RF (100 µA to 1.6 mA), IF (100 µA or 800 µA)
- Digital filtered lock detect and FastLock™ mode
- Three-wire MICROWIRE interface for serial data transfer
- Available in 24-pin TSSOP and 24-pin CSP surface mount plastic packages
Applications
- Portable wireless communications (PCS/PCN, cordless phones)
- Wireless local area networks (WLAN)
- Cellular and satellite communications
- Radio transceivers and local oscillator subsystems
Q & A
- What is the LMX2352TM/NOPB used for? The LMX2352TM/NOPB is used in local oscillator subsystems for radio transceivers to generate stable, low-noise control signals for VCOs.
- What is the operating voltage range of the LMX2352TM/NOPB? The device operates from 2.7 V to 5.5 V.
- What are the typical current consumption values for the LMX2352TM/NOPB? Typically, the current consumption is 4.75 mA at 3.0 V.
- What are the prescale ratios available for the RF PLL in the LMX2352TM/NOPB? The prescale ratios available are 8/9 or 16/17.
- How is the charge pump current programmable in the LMX2352TM/NOPB? The RF charge pump current is programmable from 100 µA to 1.6 mA in 100 µA steps, and the IF charge pump is set to either 100 µA or 800 µA.
- What interface is used for serial data transfer in the LMX2352TM/NOPB? A three-wire MICROWIRE interface is used for serial data transfer.
- In what packages is the LMX2352TM/NOPB available? It is available in 24-pin TSSOP and 24-pin CSP surface mount plastic packages.
- What is the power down current for the LMX2352TM/NOPB? The power down current is typically between 5 µA and 20 µA.
- What are some common applications of the LMX2352TM/NOPB? Common applications include portable wireless communications, WLAN, cellular and satellite communications, and radio transceivers.
- How does the LMX2352TM/NOPB handle power down modes? The device has programmable or logical power down modes, and when powered down, the charge pump and phase comparator logic go into a TRI-STATE condition.
