Features
| • | 350 MHz bandwidth |
| • | Differential input and output |
| • | Gain control: parallel w/data latching |
| • | Supply voltage: +5V |
| • | Supply current: 48 mA |
Description The CLC5526 is a high performance, digitally controlled, variable-gain amplifier (DVGA). It has been designed for use in a broad range of mixed signal and digital communication applications such as mobile radio, cellular base stations and back-channel modems where automatic-gain-control (AGC) is required to increase system dynamic range.
The CLC5526 has differential input and output, allowing large signal swings on a single 5V rail. The input impedance is 200 . The differential output impedance is 600 and is designed to drive a 1 k differential load. The output amplifier has excellent intermodulation performance. The CLC5526 is designed to accept signals from RF elements and maintain a terminated impedance environment.
The CLC5526 maintains a 350 MHz bandwidth over its entire gain and attenuation range from +30 dB to -12 dB. Internal clamping ensures very fast overdrive recovery. Two tone intermodulation distortion is excellent: at 150 MHz, 1 Vpp it is -64 dBc.
Input signals to the CLC5526 are scaled by an accurate, differential R-2R resistive ladder with an input impedance of 200. A scaled version of the input is selected under digital control and passed to the internal amplifier. The input common mode level is set at 2.4V via a bandgap referenced bias generator which can be overridden by an external input.
Following the resistive ladder is a fixed, 30 dB gain amplifier. The output stage common mode voltage of the CLC5526 is set to 3V, by internal, positive supply connected resistors.
Digital control of the CLC5526 is accomplished by a 3-bit parallel gain control input and a data valid pin to latch the data. If the data is not latched, the DVGA is transparent to gain control updates. All digital inputs are TTL/CMOS compatible.
A shutdown input reduces the CLC5526 supply currrent to a few mA. During shutdown, the input termination is maintained and current attenuation settings are held.
The CLC5526 operates over the industrial temperature range of -40°C to +85°C. The part is available in a 20-pin SSOP package.
Key Specification
| • | Low two tone intermod: distortion: -64 dBc @ 1 VPP, 150 MHz 24.5 dBm IP3, 150 MHz |
| • | Low noise: 2.5 nV/SqrtHz (max gain), 9.3 dB noise figure (max gain) |
| • | Wide gain range: +30 dB to -12 dB |
| • | Gain step size: 6 dB |
Applications
| • | Cellular/PCS base stations |
| • | IF sampling receivers |
| • | Infrared/CCD imaging |
| • | Back-channel modems |
| • | Electro-optics |
| • | Instrumentation |
| • | Medical imaging |
| • | High definition video |
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