ISL84714IHZ-T Intersil, ISL84714IHZ-T Datasheet - Page 7

• Manufacturer Part Number: ISL84714IHZ-T
• Description: IC SWITCH SPDT SC70-6
• Manufacturer: Intersil

Specifications of ISL84714IHZ-T

• Function: Switch
• Circuit: 1 x SPDT
• On-state Resistance: 600 mOhm
• Voltage Supply Source: Single Supply
• Voltage - Supply, Single/dual (±): 1.65 V ~ 3.6 V
• Current - Supply: 0.018µA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 6-TSSOP, SC-88, SOT-363
• Rohs Compliant: YES
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ISL84714IHZ-TR

Logic inputs can easily be protected by adding a 1kΩ
resistor in series with the input (see Figure 8). The resistor
limits the input current below the threshold that produces
permanent damage, and the sub-microamp input current
produces an insignificant voltage drop during normal
operation.
This method is not acceptable for the signal path inputs.
Adding a series resistor to the switch input defeats the
purpose of using a low r
diodes can be added in series with the supply pins to provide
overvoltage protection for all pins (see Figure 8). These
additional diodes limit the analog signal from 1V below V+ to
1V above GND. The low leakage current performance is
unaffected by this approach, but the switch signal range is
reduced and the resistance may increase, especially at low
supply voltages.
Power-Supply Considerations
The ISL84714 construction is typical of most single supply
CMOS analog switches, in that they have two supply pins:
V+ and GND. V+ and GND drive the internal CMOS
switches and set their analog voltage limits. Unlike switches
with a 4V maximum supply voltage, the ISL84714 4.8V
maximum supply voltage provides plenty of room for the
10% tolerance of 3.6V supplies, as well as room for
overshoot and noise spikes.
The minimum recommended supply voltage is 1.65V but the
part will operate with a supply below 1.5V. It is important to
note that the input signal range, switching times, and
ON-resistance degrade at lower supply voltages. Refer to
the “Electrical Specifications” Table beginning on page 3 and
“Typical Performance Curves” on page 8 for details.
V+ and GND also power the internal logic and level shifters.
The level shifters convert the input logic levels to switched
V+ and GND signals to drive the analog switch gate
terminals.
OPTIONAL
PROTECTION
RESISTOR
FIGURE 8. OVERVOLTAGE PROTECTION
IN
V
NO or NC
X
ON
switch, so two small signal
GND
7
V+
OPTIONAL PROTECTION
DIODE
OPTIONAL PROTECTION
DIODE
V
COM
ISL84714
This family of switches cannot be operated with bipolar
supplies, because the input switching point becomes
negative in this configuration.
Logic-Level Thresholds
This switch family is 1.8V CMOS compatible (0.5V and 1.4V)
over a supply range of 2V to 3.6V (see Figure 15). At 3.6V
the V
guaranteed high output minimum level of 1.4V, but noise
margin is reduced.
The digital input stages draw supply current whenever the
digital input voltage is not at one of the supply rails. Driving
the digital input signals from GND to V+ with a fast transition
time minimizes power dissipation.
High-Frequency Performance
In 50Ω systems, signal response is reasonably flat even past
90MHz (see Figure 16). The frequency response is very
consistent over a wide V+ range, and for varying analog
signal levels.
An OFF switch acts like a capacitor and passes higher
frequencies with less attenuation, resulting in signal
feedthrough from a switch’s input to its output. OFF Isolation
is the resistance to this feedthrough, while crosstalk
indicates the amount of feedthrough from one switch to
another. Figure 17 details the high OFF Isolation and
crosstalk rejection provided by this family. At 1MHz, Off
Isolation is about 50dB in 50Ω systems, decreasing
approximately 20dB per decade as frequency increases.
Higher load impedances decrease OFF Isolation and
crosstalk rejection due to the voltage divider action of the
switch OFF impedance and the load impedance.
Leakage Considerations
Reverse ESD protection diodes are internally connected
between each analog-signal pin and both V+ and GND. One of
these diodes conducts if any analog signal exceeds V+ or
GND.
Virtually all the analog leakage current comes from the ESD
diodes to V+ or GND. 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 GND 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 GND 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 terminal. 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 GND.
IH
level is about 1.1V. This is still below the 1.8V CMOS
January 19, 2009
FN6086.3