Datasheet

Detailed Description
The MAX14756/MAX14757/MAX14758 are analog
switches with low on-resistance of 10Ω (max) that
conduct equally well in both directions. All devices have
a rail-to-rail analog-signal range. They operate with a
single +70V supply in unipolar applications or ±35V dual
supplies in bipolar applications. The bipolar supplies can
be offset and do not have to be symmetrical.
The MAX14756 is a quad NC SPST switch, the MAX14757
is a quad NO SPST switch, and the MAX14758 has two
NO and two NC SPST switches. These switches have 5Ω
(typ) on-resistances and low on-leakage currents of 5nA
(max). The on-resistance flatness is 0.004Ω (typ). These
devices are suitable for a multitude of analog-signal
routing and switching applications, and are functonally
operational up to +125°C with increased leakage currents.
Applications Information
Low-Distortion Audio
The MAX14756/MAX14757/MAX14758 switches, having
low R
ON
and very low R
ON
variation with signal ampli-
tude, are well suited for low-distortion audio applications.
The Typical Operating Characteristics section shows
Total Harmonic Distortion (THD) vs. Frequency graphs for
several signal amplitudes.
Current Through the Switches
The current flowing through every switch must be limited
to ±50mA for normal operation. If the current exceeds this
limit, an internal leakage current flows from the switch to
V
SS
. Larger input currents do not destroy the device, as
long as the Absolute Maximum Ratings are not exceeded.
Input-Voltage Clamping
For applications that require input voltages beyond the
supplies rails, the internal input diodes to V
DD
and V
SS
can be used to limit the input voltages. As shown in Figure
9, series resistors can be employed at the inputs to limit
the currents flowing into the diodes during undervoltage
and overvoltage conditions. Choose the limiting resistors
such that the input currents are limited to IIN_(MAX) = 100mA.
The values of the current-limit resistors can be calculated
as the larger of R
LIM+
and R
LIM-
.
IN DD
LIM
IN_
V (MAX) V
R
I (MAX)
+
−
=
SS IN
LIM
IN_
V V (MIN)
R
I (MAX)
−
−
=
During an undervoltage or overvoltage condition, the
input impedance is equal to R
LIM
. The additional power
dissipation due to the fault currents needs to be calcu-
lated. During an overvoltage or undervoltage clamping
condition on one switch input, the other switches of the
MAX14756/MAX14757/MAX14758 operate normally.
Beyond-the-Rail Input
If input voltages are expected to go beyond the supply
voltages, but within the absolute maximum supply volt-
ages of the MAX14756/MAX14757/MAX14758, add two
diodes in series with the supplies as shown in Figure 10.
Table 1. MAX14756 Truth Table
Table 2. MAX14757 Truth Table
Table 3. MAX14758 Truth Table
LOGIC SWITCH
EN1 0 A1/B1 Closed
EN2 0 A2/B2 Closed
EN3 0 A3/B3 Closed
EN4 0 A4/B4 Closed
EN1 1 A1/B1 Open
EN2 1 A2/B2 Open
EN3 1 A3/B3 Open
EN4 1 A4/B4 Open
LOGIC SWITCH
EN1 0 A1/B1 Open
EN2 0 A2/B2 Open
EN3 0 A3/B3 Open
EN4 0 A4/B4 Open
EN1 1 A1/B1 Closed
EN2 1 A2/B2 Closed
EN3 1 A3/B3 Closed
EN4 1 A4/B4 Closed
LOGIC SWITCH
EN1 0 A1/B1 Closed
EN2 0 A2/B2 Open
EN3 0 A3/B3 Open
EN4 0 A4/B4 Closed
EN1 1 A1/B1 Open
EN2 1 A2/B2 Closed
EN3 1 A3/B3 Closed
EN4 1 A4/B4 Open
MAX14756/MAX14757/
MAX14758
Quad SPST +70V Analog Switches
www.maximintegrated.com
Maxim Integrated │ 10