MAX4517
__________Applications Information
Power-Supply Considerations
The MAX4516/MAX4517 operate with power-supply
voltages from ±1V to ±6V, but are tested and guaran-
teed only with ±5V supplies. Similarly, they will operate
with a single +2V to +12V supply, but logic-level inputs
can shift with higher voltages. The pin-compatible
MAX4514/MAX4515 are recommended for use with a
single supply.
The MAX4516/MAX4517 construction is typical of most
CMOS analog switches, except that they have only two
supply pins: V+ and V-. V+ and V- drive the internal
CMOS switches and set their analog voltage limits.
Reverse ESD-protection diodes are internally connected
between each analog-signal pin and both V+ and V-.
One of these diodes conducts if any analog signal
exceeds V+ or V-.
Virtually all the analog leakage current comes from the
ESD diodes to V+ or V-. Although the ESD diodes on a
given signal pin are identical and therefore fairly well
balanced, they are reverse biased differently. Each is
biased by either V+ or V- and the analog signal. This
means their leakages will vary as the signal varies. The
difference in the two diode leakages to the V+ and V-
pins constitutes the analog-signal-path leakage current.
All analog leakage current flows between each pin and
one of the supply terminals, not to the other switch ter-
minal. This is why both sides of a given switch can
show leakage currents of the same or opposite polarity.
There is no connection between the analog-signal
paths and V+ or V-.
V+ and V- also power the internal logic and logic-level
translators. The logic-level translators convert the logic
levels to switched V+ and V- signals to drive the analog
signal gates.
Logic-Level Thresholds
The logic-level thresholds are CMOS-compatible but
not TTL-compatible. Since these parts have no
ground pin, the logic-level threshold is referenced to
V+. The threshold limits are V+ = -1.5V and V+ = -3.5V
for V+ levels between +6V and +3V. When V+ = +2V,
the logic threshold is approximately 0.6V.
Do not connect the MAX4516/MAX4517’s V+ to +3V
and then connect the logic-level pins to logic-level
signals that operate from a +5V supply. TTL levels
can exceed +3V and violate the absolute maximum
ratings, damaging the part and/or external circuits.
High-Frequency Performance
In 50Ω systems, signal response is reasonably flat up
to 250MHz (see
Typical Operating Characteristics
).
Above 20MHz, the on response has several minor
peaks that are highly layout dependent. The problem is
not in turning the switch on; it’s in turning it off. The off-
state switch acts like a capacitor and passes higher fre-
quencies with less attenuation. At 10MHz, off isolation is
about -48dB in 50Ω systems, decreasing (approximate-
ly 20dB per decade) as frequency increases. Higher cir-
cuit impedances also cause off isolation to decrease.
Off isolation is about 3dB above that of a bare IC sock-
et, and is due entirely to capacitive coupling.
MAX4516/MAX4517
Dual-Supply, Low-On-Resistance,
SPST, CMOS Analog Switches
_______________________________________________________________________________________ 5
______________________________________________________________Pin Description
SOT23-5DIP/SO SOT23-5DIP/SO
Analog Switch (normally closed)——
3
2
4
5
—
Negative Supply-Voltage Input (analog and digital)
1
7
Analog Switch (normally open)8
28
3
Digital Control Input
—
6
Positive Supply-Voltage Input (analog and digital)
4
4
No Connect (not internally connected)
5
2, 3, 5
Analog Switch Common Terminal1
—
1
7
—
6
4
2, 3, 5
1
NC
V-
NO
IN
V+
N.C.
COM
Note: NO, NC, and COM pins are identical and interchangeable. Any may be considered as an input or an output; signals pass
equally well in both directions.
NAME FUNCTIONMAX4516 MAX4517
PIN
