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Injection Current Control Eliminates External Protection Circuits
NXP´s 74HC4851 and 74HC4852 are
analog multiplexer/demultiplexers that
include circuitry to control the effect
of injection currents. The 74HC4851
(single 8-channel) and the 74HC4852
(2x 4-channel with shared control pins)
are pin compatible with the 74HC4051
and 74HC4052 respectively. Apart from
SO and TSSOP packages, the devices are
also offered in the thermally enhanced
DQFN package.
The additional injection current effect
control circuitry allows signals at disabled
analog input channels to exceed the supply
voltage without affecting the signal of
the enabled analog channel.
This feature
has excellent value in industrial and automotive
monitoring applications where voltages
in excess of the supply voltage are
common and external components are
needed when using the previous 74HC405x mux/demux devices.
Protection circuits are no longer
required
Due to the injection current control feature
of the 74HC4851 and 74HC4852 analog
multiplexer/demultiplexers, external diode/
resistor protection circuits are no longer required; saving cost and space.
The figures
below show the same automotive monitoring
application using the 74HC4051 that
requires external components (left figure),
or using the 74HC4851 with injection current
control, eliminating the need for protection
circuits (right figure).
Product Features
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Injection current control |
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Wide supply voltage range: 2 V to 6 V |
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Temperature range: -40 to +125 °C |
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74HC4852 switches I/O-pairs for
differential signals and/or current loops |
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Low on-state resistance, e. g. 400Ω typ.
at 2 V, 120Ω typ. at 3.3 V, 59Ω typ. at 6 V |
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Pin compatible with 74HC4051 and
74HC4052 |
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Available in SO, TSSOP and DQFN
packages |
Information Service
Product Data Sheet
Ordering Information
Additional Information
For more details regarding NXP´s analog
multiplexer/demultiplexers, simply contact
your SPOERLE representative or visit
www.nxp.com
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