Low-Voltage, Single-Supply,
10鈩?SPST CMOS Analog Switches
MAX4594鈥揗AX4597
Applications Information
Analog Signal Levels
Analog signals can range over the supply voltage (V+
to GND) with on-resistance changing very little over the
entire range (see
Typical Operating Characteristics).
The MAX4594鈥揗AX4597 are bidirectional, so the NO,
NC, and COM pins can be used either as inputs or out-
puts.
POSITIVE SUPPLY
D1
V+
Power-Supply Sequencing and
Overvoltage Protection
Proper power-supply sequencing is recommended for
all CMOS devices. Always apply V+ before applying
analog signals or logic inputs, especially if the analog
or logic signals are not current limited. If this sequenc-
ing is not possible, and if the analog or logic inputs are
not current limited to <20mA, add a small-signal diode
(D1) as shown in Figure 1. If the analog signal can dip
below GND, add D2. Adding protection diodes
reduces the analog signal range to a diode drop (about
0.7V) below V+ for D1 or to a diode drop above ground
for D2. The addition of diodes does not affect leakage.
On-resistance increases by a small amount at low sup-
ply voltages. Maximum supply voltage (V+) must not
exceed 6V.
Protection diodes D1 and D2 also protect against some
overvoltage situations. A fault voltage up to the absolute
maximum rating at an analog signal input does not dam-
age the device, even if the supply voltage is below the sig-
nal voltage.
Vg
NO
OR
NC
COM
GND
D2
Figure 1. Overvoltage Protection Using Two External Blocking
Diodes
Chip Information
TRANSISTOR COUNT: 50
Test Circuits/Timing Diagrams
V+
V+
V+
V
NO
or V
NC
= 0
V
IN
0
MAX4594/MAX4596
V
OUT
C
L
1000pF
V
OUT
鈭哣
OUT
MAX4595/MAX4597
V
IN
IN
MAX4594
MAX4595
MAX4596
MAX4597
COM
GND
NO
or
NC
50鈩?/div>
鈭哣
OUT
IS THE MEASURED VOLTAGE DUE TO CHARGE TRANSFER
ERROR Q WHEN THE CHANNEL TURNS OFF.
Q =
鈭哣
OUT
x C
L
Figure 2. Charge Injection
6
_______________________________________________________________________________________
                         
                        
                        prev
                        
                        next