Low-Voltage, Dual SPDT, Audio Clickless
Switches with Negative Rail Capability
SOURCE 1 OUT-
SOURCE 2 OUT- NO2
Figure 1. Typical Operating Circuit
The MAX4762–MAX4764/MAX4764A/MAX4765 are low
on-resistance, low-voltage, dual SPDT analog switches
that operate from a +1.8V to +5.5V supply and are fully
specified for nominal 3.0V applications. The devices
feature a negative signal capability that allows signals
below ground to pass through without distortion and
have break-before-make switching.
The MAX4763/MAX4765 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. The MAX4764/MAX4764A/MAX4765 feature an
internal shunt switch to discharge any capacitance at the
NO and NC connection points. This reduces the click-
and-pop sounds that occur when switching audio signals.
Digital Control Inputs
The MAX4762–MAX4764/MAX4764A/MAX4765 logic
inputs accept up to +5.5V, regardless of supply voltage.
For example, with a +3.3V 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 consumption. For a +1.8V 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 2.0V (high).
Analog Signal Levels
The on-resistance of the MAX4762–MAX4764/
MAX4764A/MAX4765 changes very little for analog input
signals across the entire supply voltage range (see the
Typical Operating Characteristics). The switches are bidi-
rectional, so the NO_, NC_, and COM_ pins can be either
inputs or outputs.
The MAX4762–MAX4764/MAX4764A/MAX4765 pass
signals as low as VCC - 5.5V, including signals below
ground with minimal distortion.
The MAX4763/MAX4765 include a comparator that can
be used for mute and headphone detection functions.
The positive terminal of the comparator is internally set to
VCC / 3. When the negative terminal (CMP-) is below the
threshold, the comparator output (CMPO) is a logic high.
When CMP- rises above VCC / 3, CMPO is a logic low.
The comparator threshold of VCC / 3 allows for detection
of headphones because headphone audio signals are
typically biased to VCC / 2.
The 100Ω shunt switches on the MAX4764/MAX4764A/
MAX4765 automatically discharge any capacitance at
the NC_ or NO_ terminals when they are unconnected
to COM_. This reduces audible click-and-pop sounds
that occur when switching between audio sources.
Audible clicks and pops are caused when a step DC
voltage is switched into the speaker. By automatically
discharging the side that is not connected, any residual
DC voltage is removed, thereby reducing the clicks
Power-Supply Sequencing and
Caution: Do not exceed the absolute maximum ratings
since 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
UCSP Applications Information
For the latest application details on UCSP construction,
dimensions, tape carrier information, printed circuit board
techniques, bump-pad layout, and recommended reflow
temperature profile, as well as the latest information on
reliability testing results, go to the Maxim’s website at
www.maxim-ic.com/ucsp and search for the Application
Note, “UCSP—A Wafer-Level Chip-Scale Package.”