AD8174ARZ Analog Devices Inc, AD8174ARZ Datasheet - Page 9

• Manufacturer Part Number: AD8174ARZ
• Description: IC MUX SWITCHNG W/AMP 4:1 14SOIC
• Manufacturer: Analog Devices Inc

Specifications of AD8174ARZ

• Applications: Multiplexer with Amplifier
• Voltage - Supply: ±4 V ~ 6 V
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Mounting Type: Surface Mount
• No. Of Circuits: 4
• Supply Current: 9.7mA
• Supply Voltage Range: ± 4V To ± 6V
• Operating Temperature Range: -40°C To +85°C
• Analog Switch Case Style: SOIC
• No. Of Pins: 14
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Interface: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

Equation 4 can be used to calculate expected gain error due to
the current feedback amplifier’s finite transimpedance and
common mode rejection. For low gains and recommended
feedback resistors, this will be typically less than 0.4%. For
most applications with gain greater than 1, the dominant source
of gain error will most likely be the ratio-match of the external
resistors. All of the dominant contributors to gain error are
associated with the buffer amplifier and external resistors.
These do not change as different channels are selected, so
channel-to-channel gain match of less than 0.05% is easily
attained.
R
R
CMRR = Amplifier Common-Mode Rejection –52 dB
Choice of External Resistors
The gain and bandwidth of the multiplexer are determined by
the closed-loop gain and bandwidth of the onboard current
feedback amplifier. These both may be customized by the
external resistor feedback network. Table III shows typical
bandwidths at some common closed loop gains for given
feedback and gain resistors (R
The choice of R
frequency response must be maintained. The resistors recom-
mended in the table result in the widest 0.1 dB bandwidth with
the least peaking. 1% resistors are recommended for applications
requiring the best control of bandwidth. Packaging parasitics vary
between DIP and SOIC packages, which may result in a slightly
different resistor value for optimum frequency performance.
Wider bandwidths than those listed in the table can be attained
by reducing R
To estimate the –3 dB bandwidth for feedback resistors not
listed in Table III, the following single-pole model for the
current feedback amplifier may be used:
REV. 0
C
(pF)
20
50
100
300
T
IN
L
G
Ideal Gain
= Amplifier Transresistance = 600 k
= Amplifier Input Resistance 100
1
R
( )
1 k
1 k
2k
2k
F
R
R
G
F
F
Table IV. Recommended Feedback and Series Resistors and Bandwidth vs. Capacitive Load and Gain
at the expense of increased peaking.
F
R
R
( )
50
30
20
20
T
is not critical unless the widest and flattest
SOUT
A
CL
G = +1
R
IN
Error Terms
1 sC
R
1
T
V
–3 dB BW
(MHz)
149
104
73
27
R
R
OUT
F
T
F
G
and R
R
= 2 V p-p
F
G
R
F
G
G
, respectively).
N
1 CMRR
R
IN
R
( )
1 k
1 k
1 k
1 k
F
R
( )
20
15
15
15
SOUT
G = +2
(4)
V
–3 dB BW
(MHz)
174
117
80
34
–9–
OUT
A
C
R
G = Ideal Closed Loop Gain
G
R
The –3 dB bandwidth is determined from this model as:
This model is typically good to within 15%.
AD8170R +1
AD8174R +1
Capacitive Load
The general rule for current feedback amplifiers is that the
higher the load capacitance, the higher the feedback resistor
required for stable operation. For the best combination of wide
bandwidth and clean pulse response, a small output resistor is
also recommended, as shown in Figure 24. Table IV contains
values of feedback and series resistors that result in the best
pulse response for a given load capacitance.
= 2 V p-p
CL
T
F
IN
N
V
= Feedback Resistor
= Transcapacitance
= (1 + R
= Inverting Terminal Input Resistance 100
IN
= Closed Loop Gain
50
Figure 24. Circuit for Driving a Capacitive Load
R
T
Table III. Recommended Component Values
Gain R
+2
+10
+20
+2
+10
+20
SWITCH
F
/R
R
( )
499
1 k
1 k
1 k
1 k
499
499
499
1 k
549
499
499
G
F
F
) = Noise Gain
R
( ) R
G
f
–3 dB
R
( )
25
15
15
15
—
499
54.9
26.3
—
549
54.9
26.3
SOUT
BUFFER
G
–V
+V
2 C
( ) –3 dB BW (MHz) –3 dB BW (MHz)
G = +3
S
0.8 pF
S
0.1µF
R
10µF
Small Signal
V
710
250
50
27
780
235
50
27
T
F
V
–3 dB BW
(MHz)
170
98
71
33
OUT
0.1µF
10µF
OUT
R
AD8170/AD8174
F
= 50 mV rms V
1
= 2 V p-p
G
R
N
S(OUT)
R
IN
C
Large Signal
270
290
55
27
270
280
55
27
L
OUT
R
( )
499
499
499
499
V
(TO FET PROBE)
OUT
F
G
= 0.707 V rms
+4
R
( )
20
20
15
15
SOUT