- There is an adjustable gain over a 42 dB range
- Precision 6.02 dB gain step
- Parallel 3-bit gain control
- Gain setting in on-chip registers
- Fully differential signal path
- Single-ended to differential capability
- 200Ω input impedance
- LLP package with small footprint (4mm x 4mm).
illustrate
The LMH6514 is a high performance, digitally controlled variable gain amplifier (DVGA). It combines a low noise precision, ultralinear differential amplifier gain control. Typically, the LMH6514 is a high-performance ADC driver in a wide range of mixed-signal and digital communications applications such as mobile radios and cellular base station stations that require automatic gain control (AGC) to increase the dynamic range of the system. When used with a high-speed ADC, the dynamic range of the system can be extended to 42 dB.
The LMH6514 features differential inputs and outputs that allow large signal swings from a single 5V supply. Its purpose is to accept signals from RF components and maintain a terminated impedance environment. The input impedance is a 200Ω resistor. The output impedance is 200Ω or 400Ω and is user selectable. A unique internal structure allows the use of two single-ended and differential input signals.
The LMH6514 scales the input signal for high linearity, digitally controlled attenuators with seven accurate 6 dB steps. The output of the attenuator provides a high gain, ultralinear differential transconductance of the input signal. Transconductance differential output current can be converted to voltage using an on-chip 200Ω or 400Ω load. The transconductance gain is 0.1 amps/volt at a maximum voltage gain of +32 dB when driving a 400Ω load, while driving a 200Ω load, or 38 dB. The gain settings provided by the on-chip digital latch are stored locally. The settling time for the gain step is 5ns, and care has been taken to reduce the bandwidth and phase sensitivity gain settings.
The LMH6514 operates over an industrial temperature range of -40°C to +85°C The LMH6514 is available in a 16-pin, thermally enhanced, LLP package.
Main specifications
- 600 MHz bandwidth in a 100 Ω load
- OIP3,200 Ω load at 39 dBm at 75 MHz
- 26 dB to 38 dB maximum gain
- Selectable output impedance 200Ω or 400Ω.
- 8.3 dB noise figure
- 5 ns gain step switching time
- The supply current is 100 mA
apply
- Cellular base stations
- IF sampling receiver
- Instrumentation
- modem
- imaging
- Differential line receiver
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