Improved, SPST/SPDT Analog Switches
DG417/DG418/DG419
______________________________________________________________Pin Description
PIN
DG417
1
—
—
2
3
4
5
6
7
8
—
DG418
—
1
—
2
3
4
5
6
7
8
—
DG419
—
—
2
—
3
4
5
6
7
1
8
NAME
S
S
S1
N.C.
GND
V+
VL
IN
V-
D
S2
FUNCTION
Analog-Switch Source Terminal (normally closed)
Analog-Switch Source Terminal (normally open)
Analog-Switch Source Terminal 1 (normally closed)
No Internal Connection
Logic Ground
Analog-Signal Positive Supply Input
Logic-Level Positive Supply Input
Logic-Level Input
Analog-Signal Negative Supply Input
Analog-Switch Drain Terminal
Analog-Switch Source Terminal 2 (normally open)
__________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.)
V+
S
D
V
g
DG41_
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).
V-
Figure 1. Overvoltage Protection Using External Blocking Diodes
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.
6
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