AD8027AR-REEL7 Analog Devices Inc, AD8027AR-REEL7 Datasheet - Page 21

• Manufacturer Part Number: AD8027AR-REEL7
• Description: IC OPAMP R-R LDIST LN LP 8SOIC
• Manufacturer: Analog Devices Inc

Specifications of AD8027AR-REEL7

• Rohs Status: RoHS non-compliant
• Amplifier Type: Voltage Feedback
• Number Of Circuits: 1
• Output Type: Rail-to-Rail
• Slew Rate: 100 V/µs
• -3db Bandwidth: 190MHz
• Current - Input Bias: 4µA
• Voltage - Input Offset: 200µV
• Current - Supply: 6.5mA
• Current - Output / Channel: 120mA
• Voltage - Supply, Single/dual (±): 2.7 V ~ 12 V, ±1.35 V ~ 6 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Gain Bandwidth Product: -

APPLICATIONS
USING THE SELECT PIN
The AD8027/AD8028’s unique SELECT pin has two functions:
•
•
Table 6 lists the SELECT pin’s required voltages and modes.
Table 6. SELECT Pin Mode Control
Mode
Disable
Crossover Referenced
–1.2 V to Positive
Supply
Crossover Referenced
+1.2 V to Negative
Supply
When the input stage transitions from one input differential
pair to the other, there is virtually no noticeable change in the
output waveform.
The disable time of the AD8027/AD8028 amplifiers is load-
dependent. Typical data is presented in Table 7. See Figure 52
and Figure 53 for the actual switching measurements.
Table 7. DISABLE Switching Speeds
Time
t
t
DRIVING A 16-BIT ADC
With the adjustable crossover distortion selection point and low
noise, the AD8028 is an ideal amplifier for driving or buffering
input signals into high resolution ADCs such as the AD7767, a
16-bit, 1 LSB INL, 1 MSPS differential ADC. Figure 60 shows
the typical schematic for driving the ADC. The AD8028 driving
the AD7677 offers performance close to non-rail-to-rail
amplifiers and avoids the need for an additional supply other
than the single 5 V supply already used by the ADC.
ON
OFF
The power-down function places the AD8027/AD8028 into
low power consumption mode. In power-down mode, the
amplifiers draw 450 μA (typical) of supply current.
The second function, as mentioned in the Theory of
Operation section, shifts the crossover point (where the
NPN/PNP input differential pairs transition from one to the
other) closer to either the positive supply rail or the negative
supply rail. This selectable crossover point allows the user to
minimize distortion based on the input signal and environ-
ment. The default state is 1.2 V from the positive power
supply, with the SELECT pin left floating or in three-state.
±5 V
45 ns
980 ns
Supply Voltages (R
V
−5 to −4.2
−4.2 to
−3.3
−3.3 to +5
S
+5 V
50 ns
1100 ns
= ±5 V
SELECT Pin Voltage (V)
V
0 to 0.8
0.8 to 1.7
1.7 to 5.0
S
= +5 V
L
= 1 kΩ)
+3 V
1150 ns
50 ns
V
0 to 0.8
0.8 to 1.7
1.7 to 3.0
S
= +3 V
Rev. C | Page 21 of 24
In this application, the SELECT pins are biased to avoid the
crossover region of the AD8028 for low distortion operation.
Summary test data for the schematic shown in Figure 60 is
listed in Table 8.
ANALOG INPUT +
(0.15V TO 2.65V)
Table 8. ADC Driver Performance, f
V
Parameter
Second Harmonic Distortion
Third Harmonic Distortion
THD
SFDR
As shown in Figure 61, the AD8028 and AD7677 combination
offers excellent integral nonlinearity (INL).
ANALOG INPUT –
INPUT RANGE
OUT
= 4.7 V p-p
–0.5
–1.0
1.0
0.5
0
0
SELECT
(OPEN)
SELECT
(OPEN)
Figure 60. Unity Gain Differential Drive
–
AD8028
+
–
AD8028
+
Figure 61. Integral Nonlinearity
16384
+5V
+5V
0.1μF
0.1μF
2.7nF
CODE
32768
15Ω
15Ω
C
2.7nF
Measurement
–105 dB
–102 dB
–102 dB
+105 dBc
= 100 kHz,
AD8027/AD8028
4MHz LPF
AD7677
49152
4MHz LPF
+5V
03327-A-060
65536
03327-A-059
16 BITS