DG421/423/425
Low-Power, High-Speed, Latchable CMOS Analog Switches
Features
Benefits
Applications
D
D
D
D
D
D
D
D
D
D
D
D
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D
D
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D
Latched Control Inputs
Rail-to-Rail Analog Input Range
On-Resistance: 25 W
Fast Switching Action—tON: 170 ns
Micropower Requirements—PD: 35 nW
TTL and CMOS Logic Compatible
Low Leakage: 40 pA
mP Compatible
Wide Dynamic Range
Reduced Component Count
Low Signal Errors and Distortion
Break-Before-Make Switching Action
Battery-Compatible Operation
Data Bus Switching
Sample-and-Hold Circuits
Programmable Filters
mP Controlled Analog Systems
Portable Instruments
Telecommunication Systems
Description
The DG421/423/425 are monolithic analog switches
featuring latchable logic inputs to simplify interfacing with
microprocessors. This series combines fast switching speed
(tON: 170 ns, typ), and low on-resistance (rDS(on): 25 W ,
typ) making it ideally suited for battery powered industrial
and military applications that require microprocessor
compatible analog switches.
The DG421 has two normally open switches (SPST). The
DG423 has two single-pole, double-throw (SPDT) pairs.
The DG425 has two normally open pairs (DPST).
To achieve high-voltage ratings and superior switching
performance, the DG421 series is built on Siliconix’s high
voltage silicon gate CMOS process. Break-before-make is
guaranteed for the DG423. An epitaxial layer prevents
latchup.
Each switch conducts equally well in both directions
when on and blocks input voltages up to the supply rail
voltages when off.
The input data latches become transparent when WR is
set low. When WR goes high the latches store the logic
control data. A low on RS resets all switches to their
default state (all inputs low).
Functional Block Diagram and Pin Configuration
DG421
DG425
Dual-In-Line
Dual-In-Line
16 S1
D1
1
16
S1
WR
2
15 IN1
WR
2
15
IN1
NC
3
14 V–
D3
3
14
V–
Truth Table – DG421/DG425
NC
4
13 GND
S3
4
13
GND
WR
RS
INX
Switch
NC
5
12 VL
S4
5
12
VL
0
1
0
OFF
1
ON
Latch
1
Latch
D1
NC
6
11 V+
D4
6
11
V+
RS
7
10 IN2
RS
7
10
IN2
D2
8
D2
8
9
S2
9
Top View
S2
Logic “0” v 0.8 V
Logic “1” w 2.4 V
Top View
Updates to this data sheet may be obtained via facsimile by calling Siliconix FaxBack, 1-408-970-5600. Please request FaxBack document #70052.
Siliconix
S-52880—Rev. D, 28-Apr-97
1
