Detailed Description

low-voltage, dual SPDT analog switches that operate

from a +1.8V to +5.5V supply. The MAX4635/MAX4636

ous currents to be switched in a variety of applications.

Applications Information

Logic Inputs

The MAX4635/MAX4636 logic inputs (IN1, IN2) can be

driven up to +5.5V, regardless of the voltage on V+.

This allows interfacing to 5V logic signals while operat-

ing with a +3.3V supply voltage without external level

translation.

Analog Signal Levels

Analog signals ranging over the entire supply voltage

(V+ to GND) can be passed with very little change in

on-resistance (see Typical Operating Characteristics).

The switches are bidirectional, so the NO_, NC_, and

COM_ pins may be used as either inputs or outputs.

Power-Supply Sequencing and

Overvoltage Protection

Caution: Do not exceed the absolute maximum rat-

ings because stresses beyond the listed ratings can

cause permanent damage to the device. Proper

power-supply sequencing is recommended for all

CMOS devices. Always apply V+ before applying ana-

log signals, especially if the analog signal is not current

limited. If this sequencing is not possible, and if the

analog inputs are not current limited to less than 30mA,

add a small-signal diode (D1) as shown in Figure 5. If

the analog signal can dip below GND, add D2. Adding

protection diodes reduces the analog range to a diode

drop (about 0.7V) below V+ (for D1), and a diode drop

above ground (for D2).

Fast, Low-Voltage, Dual 4

Ω SPDT

CMOS Analog Switches

8

_______________________________________________________________________________________

CAPACITANCE

METER

NC_ OR

NO_

COM_

GND

IN_

OR

10nF

V+

f = 1MHz

V+

MAX4635

MAX4636

Figure 3. Channel Off/On-Capacitance

MEASUREMENTS ARE STANDARDIZED AGAINST SHORTS AT IC TERMINALS.

OFF-ISOLATION IS MEASURED BETWEEN COM_ AND "OFF" NO_ OR NC_ TERMINAL ON EACH SWITCH.

ON-LOSS IS MEASURED BETWEEN COM_ AND "ON" NO_ OR NC_ TERMINAL ON EACH SWITCH.

CROSSTALK IS MEASURED FROM ONE CHANNEL TO ALL OTHER CHANNELS.

SIGNAL DIRECTION THROUGH SWITCH IS REVERSED; WORST VALUES ARE RECORDED.

+5V

V+

IN_

NC_

COM_

NO_

MAX4635

MAX4636

OFF-ISOLATION = 20log

ON-LOSS = 20log

CROSSTALK = 20log

NETWORK

ANALYZER

50

Ω

50

Ω

50

Ω

50

Ω

MEAS

REF

10nF

0 OR V+

50

Ω

GND

Figure 4. On-Loss, Off-Isolation, and Crosstalk