__________Applications Information

Operation with Supply Voltages

Other than ±15V

Using supply voltages other than ±15V reduces the

analog signal range. The DG417/DG418/DG419 switch-

es operate with ±4.5V to ±20V bipolar supplies or with

a +10V to +30V single supply; connect V- to 0V when

operating with a single supply. Also, all device types

can operate with unbalanced supplies, such as +24V

and -5V. VL must be connected to +5V to be TTL com-

patible, or to V+ for CMOS-logic level inputs. The

Typical Operating Characteristics graphs show typical

on-resistance with ±20V, ±15V, ±10V, and ±5V sup-

plies. (Switching times increase by a factor of two or

more for operation at ±5V.)

Overvoltage Protection

Proper power-supply sequencing is recommended for

all CMOS devices. Do not exceed the absolute maxi-

mum ratings because stresses beyond the listed rat-

ings may cause permanent damage to the devices.

Always sequence V+ on first, followed by VL, V-, and

logic inputs. If power-supply sequencing is not possi-

ble, add two small, external signal diodes in series with

the supply pins for overvoltage protection (Figure 1).

Adding diodes reduces the analog signal range to 1V

below V+ and 1V above V-, without affecting low switch

resistance and low leakage characteristics. Device

operation is unchanged, and the difference between

V+ and V- should not exceed +44V.

Improved, SPST/SPDT Analog Switches

6

_______________________________________________________________________________________

______________________________________________________________Pin Description

FUNCTION

DG417

DG418

1

—

Analog-Switch Source Terminal (normally closed)

PIN

—

1

Analog-Switch Source Terminal (normally open)

2

2

No Internal Connection

6

6

Logic-Level Input

5

5

Logic-Level Positive Supply Input

4

4

Analog-Signal Positive Supply Input

3

3

Logic Ground

7

7

Analog-Signal Negative Supply Input

V+

D

V-

S

DG41_

Figure 1. Overvoltage Protection Using External Blocking Diodes

NAME

DG419

—

S

—

S

—

N.C.

6

IN

5

VL

4

V+

3

GND

7

V-

8

8

Analog-Switch Drain Terminal

1

D

—

—

Analog-Switch Source Terminal 1 (normally closed)

2

S1

—

—

Analog-Switch Source Terminal 2 (normally open)

8

S2