LMH6502 Datasheet, PDF (1/19 Pages) National Semiconductor (TI) – Wideband, Low Power, Linear-in-dB Variable Gain Amplifier

June 2004
LMH6502
Wideband, Low Power, Linear-in-dB Variable Gain
Amplifier
General Description
The LMH™6502 is a wideband DC coupled differential input
voltage controlled gain stage followed by a high-speed cur-
rent feedback Op Amp which can directly drive a low imped-
ance load. Gain adjustment range is more than 70dB for up
to 10MHz.
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 V_G is
tested and the tolerance is guaranteed. 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 opera-
tion, 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,
V_G 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 con-
trol applications, see the LMH6503 datasheet. The
LMH6502 is available in the SOIC-14 and TSSOP-14 pack-
age.
Features
V_S = ±5V, T_A = 25˚C, R_F = 1kΩ, R_G = 174Ω, R_L = 100Ω, A_V
= A_V(MAX) = 10 Typical values unless specified.
n -3dB BW
130MHz
n Gain control BW
100MHz
n Adjustment range (typical over temp)
70dB
n Gain matching (limit)
±0.6dB
n Slew rate
1800V/µs
n Supply current (no load)
27mA
n Linear output current
±75mA
n Output voltage (R_L = 100Ω)
±3.2V
n Input voltage noise
7.7nV/
n Input current noise
2.4pA/
n THD (20MHz, R_L = 100Ω, V_O = 2V_PP)
−53dBc
n Replacement for CLC520
Applications
n Variable attenuator
n AGC
n Voltage controller filter
n Video imaging processing
Gain vs. V_G for Various Temperature
Typical Application
20067706
LMH™ is a trademark of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation DS200677
A_VMAX = 10V/V
20067737
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