Detailed Description
The MAX4850/MAX4850H/MAX4852/MAX4852H are low
on-resistance, low-voltage, analog switches that operate
from a +2V to +5.5V single supply and are fully specified
for nominal 3.0V applications. These devices feature
over-rail signal capability that allows signals up to 5.5V
with supply voltages down to 2.0V. These devices are
configured as dual SPDT switches.
These switches have low 50pF on-channel capacitance,
which allows for 12Mbps switching of the data signals for
USB 2.0 full speed/1.1 applications. The MAX485_ _ are
designed to switch D+ and D- USB signals with a guaran-
teed skew of less than 1ns (see Figure 1), as measured
from 50% of the input signal to 50% of the output signal.
The MAX4850_ feature a comparator that can be used
for headphone or mute detection. The comparator
threshold is internally generated to be approximately 1/3
of VCC.
Applications Information
Digital Control Inputs
The logic inputs (IN_) accept up to +5.5V even if the
supply voltages are below this level. For example, with a
+3.3V VCC supply, IN_ can be driven low to GND and
high to +5.5V, allowing for mixing of logic levels in a
system. Driving IN_ rail-to-rail minimizes power con-
sumption. For a +2V supply voltage, the logic thresholds
are 0.5V (low) and 1.4V (high); for a +5V supply voltage,
the logic thresholds are 0.8V (low) and 1.8V (high).
Analog Signal Levels
The on-resistance of these switches changes very little
for analog input signals across the entire supply volt-
age range (see Typical Operating Characteristics). The
switches are bidirectional, so NO_, NC_, and COM_
can be either inputs or outputs.
Comparator
The positive terminal of the comparator is internally set to
VCC/3. When the negative terminal (CIN_) is below the
threshold (VCC/3), the comparator output (COUT_) goes
high. When CIN_ rises above VCC/3, COUT_ goes low.
The comparator threshold allows for detection of head-
phones since headphone audio signals are typically
biased to VCC/2.
Power-Supply Sequencing
Caution: Do not exceed the absolute maximum ratings
because stresses beyond the listed ratings may cause
permanent damage to the device.
Proper power-supply sequencing is recommended for
all CMOS devices. Always apply VCC before applying
analog signals, especially if the analog signal is not
current-limited.
MAX4850/MAX4850H/MAX4852/MAX4852H
Dual SPDT Analog Switches with
Over-Rail Signal Handling
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