LMH6881 Datasheet, PDF (14/35 Pages) Texas Instruments – Small Signal Bandwidth: 2400 MHz

LMH6881
SNOSC72F – JUNE 2012 – REVISED FEBRUARY 2015
Feature Description (continued)
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SOURCE
50:
AC
50:
+5V
0.01 PF
VCC
INMS
INMD
V_CM 2.5V _LMH6881
INPD
INPS
OCM
OUT+
49.9:
V_CM 2.5V
OUT-
49.9:
1.25V
0.01 PF
LOAD
100:
Figure 37. Typical Implementation With a Differential Input Signal
SOURCE
+5V
0.01 PF
50:
V_IN 2.5V INMS ^VCC
INMD
OUT+
49.9:
AC
LMH6881
V_CM 2.5V
INPD
INPS
50:
0.01 PF
OCM
2.5V
1.25V
OUT-
0.01 PF
49.9:
LOAD
100:
Figure 38. Typical Implementation With a Single-Ended Input Signal
7.4 Device Functional Modes
The LMH6881 will support two modes of control for its gain: a parallel mode and a serial mode (SPI compatible).
Parallel mode is fastest and requires the most board space for logic line routing. Serial mode is compatible with
existing SPI-compatible systems. The device has gain settings covering a range of 20 dB. In parallel mode, only
2-dB steps are available. The serial interface should be used for finer gain control of 0.25 dB for a gain between
6 dB and 26 dB of voltage gain. If fixed gain is desired, the digital pins can be strapped to ground or VCC, as
required.
The device also supports two modes of power down control to enable power savings when the amplifier is not
being used: using the SD pin (when SPI pin = Logic 0) and the power-down register (when SPI pin = Logic 1).
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