High-Speed DMOS FET Analog Switches and Switch Arrays
Introduction
This Application Note describes in detail the
principle of operation of the SD210/5000 series
of high-speed analog switches and switch
arrays. It contains an explanation of the most
important switch characteristics, application
examples, test data, and other application hints.
For surface-mount applications the SST211
series is offered in the TO-253 (SOT-143)
package. The SD5400 series comes in the
narrow body gull-wing SO-14 package.
Applications
Fast switching speeds, low on-state resistance,
high
channel-to-channel
isolation,
low
capacitance, and low charge injection make
these DMOS devices especially well suited for a
variety of applications.
A few of the many possible application areas for
DMOS analog switches are as follows:
1. Video and RF switching (high speed, high off-
isolation, low crosstalk):
-Multiple video distribution networks
-Sampling scanners for RF systems
2. Audio routing (glitch- and noise-free):
-High-speed switching
-Audio switching systems using
digitized remote control
3. Data acquisition (highspeed, low charge
injection, low leakage):
-High-speed sample-and-holds
-Audio and communication A/D
converters
4. Other:
-Digital switching
-PCM distribution networks
-UHF Amplifiers
-VHF Modulators and Double-Balanced
Mixers
-High-speed inverters/drivers
-Switched capacitor filters
-Choppers
1
Description
The Linear Systems SD210 and SD5000 series
are discretes and quad monolithic arrays,
respectively, of single-pole single-throw analog
switches.
These switches are n-channel
enhancement-mode
silicon
field
effect
transistors built using double-diffusion MOS
(DMOS) silicon gate technology. Surface-
mount versions (SST211, SD5400 Series) are
also available.
This family of devices is designed to handle a
wide variety of video, fast ATE, and telecom
analog switching applications. They are capable
of ultrafast switching speeds (t
r
= 1 ns, t
OFF
= 3
ns) and excellent transient response. Thanks to
the reduced parasitic capacitances, DMOS can
handle wideband signals with high off-isolation
and minimum crosstalk.
The SD210 series of single-channel FETs is
produced without Zener protection to reduce
leakage and in Zener protected versions to
reduce electrostatic discharge hazards. The
SD5000 series is available in 16-lead dual in-
line surface mount or sidebraze ceramic
packages. Analog signal voltage ranges up to
鹵10 V and frequencies up to 1 GHz can be
controlled.
Linear Integrated Systems, Inc.
鈼?/div>
4042 Clipper Ct.
鈼?/div>
Fremont, CA 94538
鈼?/div>
Tel: 510 490-9160
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