Features
| | Adjustable gain with a 42 dB range |
| | Precise 6.02 dB gain steps |
| | Parallel 3 bit gain control |
| | On chip register gain setting |
| | Fully differential signal path |
| | Single ended to differential capable |
| | 200Ω input impedance |
| | Small footprint (4 mm x 4 mm) LLP package |
Description The LMH6514 is a high performance, digitally controlled variable gain amplifier (DVGA). It combines precision gain control
with a low noise, ultra-linear, differential amplifier. Typically, the LMH6514 drives a high performance ADC in a broad range
of mixed signal and digital communication applications such as mobile radio and cellular base stations where automatic gain
control (AGC) is required to increase system dynamic range. When used in conjunction with a high speed ADC, system dynamic
range can be extended by up to 42 dB.
The LMH6514 has a differential input and output allowing large signal swings on a single 5V supply. It is designed to accept
signals from RF elements and maintain a terminated impedance environment. The input impedance is 200Ω resistive. The output
impedance is either 200Ω or 400Ω and is user selectable. A unique internal architecture allows use with both single ended
and differential input signals.
Input signals to the LMH6514 are scaled by a highly linear, digitally controlled attenuator with seven accurate 6 dB steps.
The attenuator output provides the input signal for a high gain, ultra linear differential transconductor. The transconductor
differential output current can be converted into a voltage by using the on-chip 200Ω or 400Ω loads. The transconductance
gain is 0.1 Amp/Volt resulting in a maximum voltage gain of +32 dB when driving a 200Ω load, or 38 dB when driving the 400Ω
load. On chip digital latches are provided for local storage of the gain setting. The gain step settling time is 5 ns and
care has been taken to reduce the sensitivity of bandwidth and phase to gain setting.
The LMH6514 operates over the industrial temperature range of −40°C to +85°C. The LMH6514 is available in a 16-Pin, thermally
enhanced, LLP package.
Key Specification
| | 600 MHz bandwidth at 100Ω load |
| | 39 dBm OIP3 at 75 MHz, 200Ω load |
| | 26 dB to 38 dB maximum gain |
| | Selectable output impedance of 200Ω or 400Ω. |
| | 8.3 dB noise figure |
| | 5 ns gain step switching time |
| | 100 mA supply current |
Applications
| | Cellular base stations |
| | IF sampling receivers |
| | Instrumentation |
| | Modems |
| | Imaging |
| | Differential line receiver |
|
Also Recommended
| ADC14155 | Complimentary ADC With 14-bit Performance |
| CLC5903 | Digital Down Converter (Diversity Receiver Chipset) |
| LM97593 | Complimentary Dual 12-bit/ 65Msps ADC + DDC (Diversity Receiver Chipset) |
| LMH6515▲ | Similar DVGA With 1dB Gain Steps And 31dB Gain Adjust Range |
|
Typical Application
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