AND8058 Datasheet, PDF (1/4 Pages) ON Semiconductor – Two New Analog Switches Set Standards for Space Efficiency

AND8058/D
Two New Analog Switches
Set Standards for Space
Efficiency
Prepared by: Fred Zlotnick
ON Semiconductor
http://onsemi.com
APPLICATION NOTE
INTRODUCTION
Analog switches that provide analog and digital switching
to circuit designers, have been around for more than
30 years. One of the most popular switches has been the
4053, a triple Single–Pole Double–Throw (SPDT) switch in
a 16–pin package. The most aggressive common package
for this device is the TSSOP–16 which occupies 32 mm² of
board space or 10.5 mm² per switch.
The hand–held wireless phenomenon is driving the need
to get more functionality into even smaller spaces. In
response, ON Semiconductor released more than
30 single–gate switches that supply exactly the right bit of
logic just where it is needed. These products were released
in industry standard SC88A/SOT–353 packages which
occupy just over 4 mm². These devices are all five leads and
provide standard logic functions. An example is the
MC74VHC1G66, a Single–Pole, Single–Throw (SPST)
analog switch.
The NLAS4599
The new NLAS4599 device is a single SPDT switch,
one–third the size of the venerable 4053, contained in an
aggressive 0.6 µ CMOS technology. It provides voltage
breakdown greater than 7.0 V, low R_on, and excellent high
frequency response. The NLAS4599 sets a new standard in
space efficiency. It occupies 4. mm² and provides the same
functionality as one–third of a 4053. Compared to the 4053,
the NLAS4599 is 2.5 times more space efficient. This is a
real boon to designers, who need to put as much
functionality as possible into every square inch.
Examples
1. Design a crystal–controlled oscillator that functions
at 32 KHz for minimum power consumption and
16 MHz for performance in a battery–operated
environment. The new NL27WZU04 provides two
unbuffered gates in a single 4 mm² package. One
gate is an oscillator; the second gate is a buffer. The
NLAS4599 is used to switch crystals. A single
control line (assumed to come from a
microcontroller) controls the frequency. When the
unit is near idle, the clock is 32 KHz and the
microcontroller/DSP functions at minimum power
consumption. When speed (performance) is
required, the clock switches to 16 MHz.
10 K
12 MΩ
V_CC
1/2 NL7WZU04
32 kHz
16 MHz ^{12 p}
OSC OUT
NLAS4599
V_CC
GND
12 p
GND
CTRL
This circuit provides dual clock rates under microprocessor control and occupies minimal board space.
Figure 1. Dual Frequency Oscillator
© Semiconductor Components Industries, LLC, 2001
1
April, 2001 – Rev. 0
Publication Order Number:
AND8058/D