7B22 Analog Devices Inc, 7B22 Datasheet - Page 2

• Manufacturer Part Number: 7B22
• Manufacturer: Analog Devices Inc

Specifications of 7B22

• Lead Free Status / Rohs Status: Not Compliant

GENERAL DESCRIPTION
The 7B22 is a unity gain single-channel signal conditioning
output module that interfaces and filters a +10 V input signal
and provides an isolated precision output of +10 V. The output
voltage appears at the 7B Series backplane screw terminal block.
Model 7B22 features a nonlinearity of +0.02% maximum and an
accuracy of +0.1% maximum (+0.01% typical). Providing 1500
V rms of galvanic transformer based isolation, output-to-input
and power, the 7B22 offers a common mode rejection (CMR) of
100 dB @ 50/60 Hz to preserve the integrity of low level signals
in noisy environments. The 7B22 is mix-and-match and hot-
swappable with other 7B Series modules, so it can be inserted or
removed from any socket in the same backplane without
disturbing system power. Model 7B22 is rated to operate with a
nominal +24 VDC supply.
The input and floating isolated voltage output of Model 7B22
are protected up to +35 VDC. The input signal from the user’s
system is buffered and then used to modulate the amplitude of a
square wave carrier. The modulated signal is transmitted across
the signal transformer and demodulated to retrieve the original
input voltage signal. This voltage is then filtered by a two-pole
low pass 400 Hz filter. The nominal +24 VDC module supply
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Figure 2
voltage powers the input side of the 7B22. The oscillator on the
input side provides the square wave carrier signal used by the
modulator and also drives the power transformer. The signal at
the secondary of the transformer is used in the demodulator
and is also converted to a DC voltage that powers the circuit on
the module’s output. The two-pole output filter and subsequent
buffer ensures that a low noise, low impedance (<1Ω) signal is
available at the isolated output to drive loads down to 5 kΩ.
7B22