The LMH6502 is a wideband DC coupled
differential input voltage controlled gain stage followed by a high-speed current feedback Op Amp
which can directly drive a low impedance load. Gain adjustment range is more than 70dB for up to
Maximum gain is set by external components and the gain can be reduced all the way to
cut-off. Power consumption is 300mW with a speed of 130MHz. Output referred DC offset voltage is
less than 350mV over the entire gain control voltage range. Device-to-device Gain matching is
within ±0.6dB at maximum gain. Furthermore, gain at any VG is tested and the
tolerance is ensured. The output current feedback Op Amp allows high frequency large signals (Slew
Rate = 1800V/μs) and can also drive heavy load current (75mA). Differential inputs allow common
mode rejection in low level amplification or in applications where signals are carried over
relatively long wires. For single ended operation, the unused input can easily be tied to ground
(or to a virtual half-supply in single supply application). Inverting or non-inverting gains could
be obtained by choosing one input polarity or the other.
To provide ease of use when working with a single supply, VG range
is set to be from 0V to +2V relative to pin 11 potential (ground pin). In single supply operation,
this ground pin is tied to a "virtual" half supply.
LMH6502 gain control is linear in dB for a large portion of the total gain control range.
This makes the device suitable for AGC circuits among other applications. For linear gain control
applications, see the LMH6503 datasheet. The LMH6502 is available in the SOIC and TSSOP
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