Low-Voltage, 60

Ω Dual

SPDT Analog Switch in Thin QFN

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7

Detailed Description

The MAX4695 is a low-voltage, dual single-pole/dou-

ble-throw (SPDT) analog switch that operates from a

single +1.8V to +5.5V supply. When powered from a

+2.7V supply, the device has a 60

Ω (max) on-resis-

logic compatible from a +2.7V to +3.3V supply.

Applications Information

Digital Control Inputs

The MAX4695 logic inputs are 1.8V CMOS logic com-

patible for 3V operation and TTL compatible for 5V

operation of V+. Driving IN_ rail-to-rail minimizes power

consumption.

Analog Signal Levels

Analog signals that range over the entire supply volt-

age (V+ to GND) are passed with very little change in

on-resistance (see Typical Operating Characteristics).

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

COM_ pins can be 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

may cause permanent damage to devices.

Proper power-supply sequencing is recommended for

all CMOS devices. Always apply V+ before applying

analog 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 <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 range to a diode

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

above ground (for D2). On-resistance increases slightly

at low supply voltages. Maximum supply voltage (V+)

must not exceed +6V.

Adding protection diode D2 causes the logic threshold

to be shifted relative to GND. TTL compatibility is not

guaranteed when D2 is added.

Protection diodes D1 and D2 also protect against some

overvoltage situations. In the circuit in Figure 1, if the

supply voltage is below the absolute maximum rating,

and if a fault voltage up to the absolute maximum rating

is applied to an analog signal pin, no damage will result.

POSITIVE SUPPLY

COM

NO

D2

D1

GND

Vg

V+

MAX4695

Figure 1. Overvoltage Protection Using Two External Blocking

Diodes

Pin Description

PIN

µMAX

TQFN

NAME

FUNCTION

1

12

IN1

Digital Control Input Switch 1

2

1

NO1

Analog Switch 1—Normally Open Terminal

3

2

GND

Ground

4

3

NO2

Analog Switch 2—Normally Open Terminal

5

4

IN2

Digital Control Input Switch 2

6

5

COM2

Analog Switch 2—Common Terminal

—

6, 10

N.C.

No Connection. Not internally connected.

7

7

NC2

Analog Switch 2—Normally Closed Terminal

8

8

V+

Positive Supply Voltage Input

9

9

NC1

Analog Switch 1—Normally Closed Terminal

10

11

COM1

Analog Common Switch 1