AD8186ARUZ-RL Analog Devices Inc, AD8186ARUZ-RL Datasheet - Page 13

IC,ANALOG MUX,TRIPLE,2-CHANNEL,BIPOLAR,TSSOP,24PIN,PLASTIC

AD8186ARUZ-RL

Manufacturer Part Number
AD8186ARUZ-RL
Description
IC,ANALOG MUX,TRIPLE,2-CHANNEL,BIPOLAR,TSSOP,24PIN,PLASTIC
Manufacturer
Analog Devices Inc
Datasheet

Specifications of AD8186ARUZ-RL

Function
Multiplexer
Circuit
3 x 2:1
On-state Resistance
350 mOhm
Voltage Supply Source
Single Supply
Voltage - Supply, Single/dual (±)
3.5 V ~ 5.5 V
Current - Supply
15mA
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
24-TSSOP (0.173", 4.40mm Width)
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
The AD8187
The AD8187 uses on-chip feedback resistors to realize the gain-
of-two function. To provide low crosstalk and a high output
impedance when disabled, each set of 500 Ω feedback resistors is
terminated by a dedicated reference buffer. A reference buffer is
a high speed op amp configured as a unity-gain follower. The
three reference buffers, one for each channel, share a single, high
impedance input, the V
current is typically less than 2 µA.
This configuration has a few implications for single-supply
operation:
1) On the AD8187, V
2) Signal at the V
REV. A
analog supply, V
Limits on Reference Voltage (AD8187, see Figure 5):
V
Using superposition, it is easily shown that
V
REF
REF
A0
Figure 5. Output Compliance of Main Amplifier
Channel and Ground Buffer
should be tied to a well bypassed, low impedance source.
V
Figure 4. Conceptual Diagram of a Single
Multiplexer Channel, G = +2
1 3
.
EE
V
V
REF
A0
B0
+
5V
5V
1 3
<
.
V
REF
REF
EE
V
V
OUT
pin appears at each output. Therefore,
.
REF
<
REF
<
V
3 4
REF
may not be tied to the most negative
=
pin (see Figure 4). V
.
5V
5V
5V
GBUF 0
5V
GBUF 1
5V
GBUF 2
2
V on
<
OUT 0
×
500
500
V
V
CC
IN
0
VF-1
VF-2
– .
500
500
V / V Supplies
V
1 6
1.3V
1.3V
1.6V
1.3V
1
REF
5
500
500
V
OUT1
OUT2
OUT 0
VFO
REF
V
REF
5V
V
V
GND
5V
V
V
GND
O_MAX
O_MIN
O_MAX
O_MIN
V
input bias
OUT
= 1.3V
= 1.3V
= 3.7V
= 3.4V
–13–
3) To maximize the output dynamic range, the reference voltage
For example, consider amplifying a 700 mV video signal with a
sync pulse 300 mV below black level. The user might decide to set
V
NPN transistor path. The AD8186 would, in this case, allow a
reference voltage as low as 1.3 V + 300 mV = 1.6 V. If the AD8187
is used, the sync pulse would be amplified to 600 mV. Therefore,
the lower limit on V
routing RGB video, an advantageous configuration would be to
employ +3 V and –2 V supplies, in which case V
tied to ground.
If system considerations prevent running the multiplexer on split
supplies, a false ground reference should be employed. A low
impedance reference may be synthesized with a second opera-
tional amplifier. Alternately, a well bypassed resistor divider
may serve. Refer to the Application section for further explana-
tion and more examples.
High Impedance Disable
Both the AD8186 and the AD8187 may have their outputs
disabled to a high impedance state. In the case of the AD8187,
the reference buffers also disable to a state of high output
impedance. This feature prevents the feedback network of a
disabled channel from loading the output, which is valuable
when busing together the outputs of several muxes.
REF
should be chosen with some care.
Figure 6a. Synthesis of a False Ground Reference
at black level to preferentially run video signals on the faster
Figure 6b. Alternate Method for Synthesis of a
False Ground Reference
100k
GND
5V
REF
10k
1 F
10k
CAP MUST BE LARGE
ENOUGH TO ABSORB
TRANSIENT CURRENTS
WITH MINIMUM BOUNCE.
becomes 1.3 V + 600 mV = 1.9 V. For
FROM 1992 ADI AMPLIFIER
APPLICATIONS GUIDE
5V
OP21
1 F
AD8186/AD8187
0.022 F
10k
V
100
REF
1 F
REF
V
REF
could be

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