MAX4855
Detailed Description
The MAX4855 dual SPDT, low on-resistance, low-voltage,
analog switch operates from a +2V to +5.5V supply and
can handle signals up to the power rails. In addition, the
MAX4855 integrates two internal comparators that can
be used for headphone or mute detection. The compara-
tor threshold is internally generated to be approximately
1/3 of V
CC
.
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 V
CC
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 voltage
range (see the Typical Operating Characteristics). The
switches are bidirectional, so the NO_, NC_, and COM_
pins can be either inputs or outputs.
Comparator
The positive terminal of the comparator is internally set to
V
CC
/3. When the negative terminal (CIN_) is below the
threshold (V
CC
/3), the comparator output (COUT_) is
high. When CIN_ rises above V
CC
/3, COUT_ is low.
The comparator threshold allows for detection of head-
phones since headphone audio signals are typically
biased to V
CC
/2.
Power-Supply Sequencing
Caution: Do not exceed the absolute maximum rat-
ings 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 V
CC
before applying
analog signals, especially if the analog signal is not
current-limited.
0.75Ω, Dual SPDT Audio Switch with
Integrated Comparators
6 _______________________________________________________________________________________
Pin Description
PIN NAME FUNCTION
1, 8 N.C. No Connection. Not internally connected.
2 CIN1 Inverting Input for Comparator 1
3 CIN2 Inverting Input for Comparator 2
4 COM1 Common Terminal for Analog Switch 1
5 NO1 Normally Open Terminal for Analog Switch 1
6 GND Ground
7 NC2 Normally Closed Terminal for Analog Switch 2
9 IN2
Digital Control Input for Analog Switch 2. A logic LOW on IN2 connects COM2 to NC2 and a logic
HIGH connects COM2 to NO2.
10 COM2 Common Terminal for Analog Switch 2
11 COUT1 Output for Comparator 1
12 NO2 Normally Open Terminal for Analog Switch 2
13 COUT2 Output for Comparator 2
14 V
CC
Supply Voltage. Bypass to GND with a 0.01µF capacitor as close to the pin as possible.
15 IN1
Digital Control Input for Analog Switch 1. A logic LOW on IN1 connects COM1 to NC1 and a logic
HIGH connects COM1 to NO1.
16 NC1 Normally Closed Terminal for Analog Switch 1
EP — Exposed Paddle. Connect to PC board ground plane.
