AD8051ARTZ-R2 Analog Devices Inc, AD8051ARTZ-R2 Datasheet - Page 19

• Manufacturer Part Number: AD8051ARTZ-R2
• Description: IC OPAMP VF R-R LDIST LP SOT23-5
• Manufacturer: Analog Devices Inc

Specifications of AD8051ARTZ-R2

• Slew Rate: 170 V/µs
• Amplifier Type: Voltage Feedback
• Number Of Circuits: 1
• Output Type: Rail-to-Rail
• -3db Bandwidth: 110MHz
• Current - Input Bias: 1.4µA
• Voltage - Input Offset: 1800µV
• Current - Supply: 4.8mA
• Current - Output / Channel: 45mA
• Voltage - Supply, Single/dual (±): 3 V ~ 12 V, ±1.5 V ~ 6 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-5, SC-74A, SOT-25
• Op Amp Type: High Speed
• No. Of Amplifiers: 1
• Bandwidth: 110MHz
• Supply Voltage Range: 3V To 12V
• Amplifier Case Style: SOT-23
• No. Of Pins: 5
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Gain Bandwidth Product: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

ANALOG-TO-DIGITAL AND DIGITAL-TO-ANALOG
APPLICATIONS
Figure 50 is a schematic showing the
for an AD9201, a 10-bit, 20 MSPS, dual analog-to-digital
converter. This converter is designed to convert I and Q signals in
communications systems. In this application, only the I channel
is being driven. The I channel is enabled by applying a logic
high to SELECT (Pin 13).
The AD8051 is running from a dual supply and is configured
for a gain of +2. The input signal is terminated in 50 Ω and the
output is 2 V p-p, which is the maximum input range of the
AD9201. The 22 Ω series resistor limits the maximum current
that flows and helps to lower the distortion of the ADC.
The AD9201 has differential inputs for each channel. These are
designated the A and B inputs. The B inputs of each channel are
connected to VREF (Pin 22), which supplies a positive reference
of 2.5 V. Each of the B inputs has a small low-pass filter that also
helps to reduce distortion.
The output of the op amp is ac-coupled into INA-I (Pin 16) via
two parallel capacitors to provide good high frequency and low
frequency coupling. The 1 kΩ resistor references the signal to
VREF that is applied to INB-I. Thus, INA-I swings both positive
and negative with respect to the bias voltage applied to INB-I.
With the sampling clock running at 20 MSPS, the analog-to-
digital output was analyzed with a digital analyzer. Two input
frequencies were used, 1 MHz and 9.5 MHz, which is just short
of the Nyquist frequency. These signals were well filtered to
minimize any harmonics.
Figure 48 shows the FFT response of the ADC for the case of a
1 MHz analog input. The SFDR is 71.66 dB, and the analog-to-
digital is producing 8.8 ENOB (effective number of bits). When
the analog frequency was raised to 9.5 MHz, the SFDR was
50Ω
3
2
AD8051
+5V
–5V
7
4
0.1µF
0.1µF
6
Figure 50. The AD8051 Driving an AD9201, a 10-Bit, 20 MSPS Analog-to-Digital Converter
10µF
10µF
AD8051
22Ω
1kΩ
1kΩ
0.33µF
0.01µF
used as a driver
+5V
1kΩ
Rev. J | Page 19 of 24
0.1µF
0.1µF
10µF
22Ω
0.1µF
10µF
0.1µF
22Ω
22Ω
10µF
10µF
0.1µF
22Ω
reduced to −60.18 dB and the ADC operated with 8.46 ENOBs
as shown in Figure 49. The inclusion of the AD8051 in the
circuit did not worsen the distortion performance of the AD9201.
0.1µF
10pF
–100
–110
–120
–100
–110
–120
10pF
–10
–20
–30
–40
–50
–60
–70
–80
–90
–10
–20
–30
–40
–50
–60
–70
–80
–90
10
10
0.1µF
0.1µF
10pF
0
0
10pF
0
0
Figure 49. FFT Plot for AD8051 Driving the AD9201 at 9.5 MHz
Figure 48. FFT Plot for AD8051 Driving the AD9201 at 1 MHz
FUND
2ND
15
16
17
18
19
20
21
22
23
24
25
26
27
28
1
1
SLEEP
INA-I
INB-I
REFT-I
REFB-I
AVSS
REFSENSE
VREF
AVDD
REFB-Q
REFT-Q
INB-Q
INA-Q
CHIP–SELECT
4TH
2ND
2
2
6TH
3RD
AD9201
3
3
FREQUENCY (MHz)
FREQUENCY (MHz)
8TH
4TH
4
4
AD8051/AD8052/AD8054
SELECT
CLOCK
5TH
DVDD
5
DVSS
5
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
6TH
6
6
14
13
12
11
10
9
8
7
6
5
4
3
2
1
7TH
7TH
7
7
5TH
8TH
8
8
0.1µF
3RD
+V
9TH
9
9
FUND
DD
DATA OUT
10µF
10
10
PART#
FFTSIZE 8192
FCLK
FUND
VIN
THD
SNR
SINAD
ENOB
SFDR
2ND
3RD
4TH
5TH
6TH
7TH
8TH
9TH
PART#
FFTSIZE 8192
FCLK
FUND
VIN
THD
SNR
SINAD
ENOB
SFDR
2ND
3RD
4TH
5TH
6TH
7TH
8TH
9TH
+5V
20.0MHz
998.5kHz
–0.51dB
–68.13
54.97
54.76
8.80
71.66
–74.53
–76.06
–76.35
–79.05
–80.36
–75.08
–88.12
–77.87
20.0MHz
9.5MHz
–0.44dB
–57.08
54.65
52.69
8.46
60.18
–60.18
–60.23
–82.01
–78.83
–81.28
–77.28
–84.54
–92.78
0
0