AD8608ARZ Analog Devices Inc, AD8608ARZ Datasheet - Page 16

• Manufacturer Part Number: AD8608ARZ
• Description: IC OPAMP GP R-R CMOS QUAD 14SOIC
• Manufacturer: Analog Devices Inc
• Series: DigiTrim®r
• Type: General Purpose Amplifierr

Specifications of AD8608ARZ

• Slew Rate: 5 V/µs
• Amplifier Type: General Purpose
• Number Of Circuits: 4
• Output Type: Rail-to-Rail
• Gain Bandwidth Product: 10MHz
• Current - Input Bias: 0.2pA
• Voltage - Input Offset: 80µV
• Current - Supply: 1mA
• Current - Output / Channel: 80mA
• Voltage - Supply, Single/dual (±): 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Op Amp Type: Precision
• No. Of Amplifiers: 4
• Bandwidth: 10MHz
• Supply Voltage Range: 2.7V To 5.5V
• Amplifier Case Style: SOIC
• No. Of Pins: 14
• Rail/rail I/o Type: Rail to Rail Input/Output
• Number Of Elements: 4
• Unity Gain Bandwidth Product: 10MHz
• Common Mode Rejection Ratio: 85dB
• Input Offset Voltage: 300uV
• Input Bias Current: 1pA
• Single Supply Voltage (typ): 3/5V
• Dual Supply Voltage (typ): Not RequiredV
• Voltage Gain In Db: 120dB
• Power Supply Rejection Ratio: 77dB
• Power Supply Requirement: Single
• Shut Down Feature: No
• Single Supply Voltage (min): 2.7V
• Single Supply Voltage (max): 5.5V
• Dual Supply Voltage (min): Not RequiredV
• Dual Supply Voltage (max): Not RequiredV
• Technology: CMOS
• Operating Temp Range: -40C to 125C
• Operating Temperature Classification: Automotive
• Mounting: Surface Mount
• Pin Count: 14
• Package Type: SOIC N
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• -3db Bandwidth: -
• Lead Free Status / Rohs Status: Compliant

AD8605/AD8606/AD8608
TOTAL NOISE INCLUDING SOURCE RESISTORS
The low input current noise and input bias current of the
AD8605 make it the ideal amplifier for circuits with substantial
input source resistance, such as photodiodes. Input offset voltage
increases by less than 0.5 nV per 1 kΩ of source resistance at
room temperature and increases to 10 nV at 85°C. The total
noise density of the circuit is
where:
e
i
R
k is Boltzmann’s constant (1.38 × 10
T is the ambient temperature in Kelvin (T = 273 + °C).
For example, with R
roughly 15 nV/√Hz.
For R
The current noise of the AD8605 is so low that its total density does
not become a significant term unless R
The total equivalent rms noise over a specific bandwidth is
expressed as
where BW is the bandwidth in hertz.
Note that the previous analysis is valid for frequencies greater
than 100 Hz and assumes relatively flat noise, above 10 kHz.
For lower frequencies, flicker noise (1/f) must be considered.
CHANNEL SEPARATION
Channel separation, or inverse crosstalk, is a measure of the signal
feed from one amplifier (channel) to another on the same IC.
The AD8606 has a channel separation of greater than −160 dB
up to frequencies of 1 MHz, allowing the two amplifiers to
amplify ac signals independently in most applications.
CAPACITIVE LOAD DRIVE
The AD860x can drive large capacitive loads without oscillation.
Figure 47 shows the output of the AD8606 in response to a
200 mV input signal. In this case, the amplifier is configured
in positive unity gain, worst case for stability, while driving a
1000 pF load at its output. Driving larger capacitive loads in
unity gain can require the use of additional circuitry.
n
n
S
is the input current noise density of the AD8605.
is the input voltage noise density of the AD8605.
is the source resistance at the noninverting terminal.
e
E
S
n
n
< 3.9 kΩ, e
,
TOTAL
=
(
e
n
,
=
TOTAL
e
n
n
)
2
dominates and e
S
+
BW
= 10 kΩ, the total voltage noise density is
(
i
n
R
S
)
2
+
4
k
TR
n, TOTAL
−23
S
J/K).
S
is greater than 6 MΩ.
≈ e
n
.
Rev. J | Page 16 of 24
A snubber network, shown in Figure 48, helps reduce the signal
overshoot to a minimum and maintain stability. Although this
circuit does not recover the loss of bandwidth induced by large
capacitive loads, it greatly reduces the overshoot and ringing.
This method does not reduce the maximum output swing of the
amplifier.
–100
–120
–140
–160
–180
200mV
–20
–40
–60
–80
Figure 47. AD8606 Capacitive Load Drive Without Snubber
0
100
V
IN
Figure 46. Channel Separation vs. Frequency
Figure 48. Snubber Network Configuration
1k
2
3
AD8605
FREQUENCY (Hz)
10k
TIME (10µs/DIV)
4
8
V+
V–
100k
1
1M
C
V
A
R
C
R
S
S
V
L
L
S
= ±2.5V
= 10kΩ
= 1000pF
= 1
10M
R
L
100M
C
L