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Teilenummer | ADA4938-1 |
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Beschreibung | Ultra-Low Distortion Differential ADC Driver | |
Hersteller | Analog Devices | |
Logo | ||
Gesamt 26 Seiten Data Sheet
FEATURES
Extremely low harmonic distortion (HD)
−106 dBc HD2 @ 10 MHz
−82 dBc HD2 @ 50 MHz
−109 dBc HD3 @ 10 MHz
−82 dBc HD3 @ 50 MHz
Low input voltage noise: 2.6 nV/√Hz
High speed
−3 dB bandwidth of 1000 MHz, G = +1
Slew rate: 4700 V/μs
0.1 dB gain flatness to 150 MHz
Fast overdrive recovery of 4 ns
1 mV typical offset voltage
Externally adjustable gain
Differential-to-differential or single-ended-to-differential
operation
Adjustable output common-mode voltage
Wide supply voltage range: +5 V to ±5 V
Single or dual amplifier configuration available
APPLICATIONS
ADC drivers
Single-ended-to-differential converters
IF and baseband gain blocks
Differential buffers
Line drivers
GENERAL DESCRIPTION
The ADA4938-1/ADA4938-2 are low noise, ultralow distortion,
high speed differential amplifiers. It is an ideal choice for
driving high performance ADCs with resolutions up to 16 bits
from dc to 27 MHz, or up to 12 bits from dc to 74 MHz. The
output common-mode voltage is adjustable over a wide range,
allowing the ADA4938-1/ADA4938-2 to match the input of the
ADC. The internal common-mode feedback loop also provides
exceptional output balance as well as suppression of even-order
harmonic distortion products.
Full differential and single-ended-to-differential gain configurations
are easily realized with the ADA4938-1/ADA4938-2. A simple
external feedback network of four resistors determines the
closed-loop gain of the amplifier.
The ADA4938-1/ADA4938-2 are fabricated using the Analog
Devices, Inc., proprietary third generation, high voltage XFCB
process, enabling it to achieve very low levels of distortion with
an input voltage noise of only 2.6 nV/√Hz. The low dc offset and
excellent dynamic performance of the ADA4938-1/ADA4938-2
Rev. B
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.
Ultralow Distortion
Differential ADC Driver
ADA4938-1/ADA4938-2
FUNCTIONAL BLOCK DIAGRAMS
ADA4938-1
TOP VIEW
–FB 1
+IN 2
–IN 3
+FB 4
12 PD
11 –OUT
10 +OUT
9 VOCM
Figure 1. ADA4938-1 Functional Block Diagram
ADA4938-2
TOP VIEW
–IN1 1
+FB1 2
+VS1 3
+VS1 4
–FB2 5
+IN2 6
18 +OUT1
17 VOCM1
16 –VS2
15 –VS2
14 PD2
13 –OUT2
Figure 2. ADA4938-2 Functional Block Diagram
–50 G = +2, VO, dm = 5V p-p
–60
G = +2, VO, dm = 3.2V p-p
G = +2, VO, dm = 2V p-p
G = +2, VO, dm = 1V p-p
–70
–80
–90
–100
–110
–120
–130
1
10
FREQUENCY (MHz)
100
Figure 3. SFDR vs. Frequency and Output Voltage
makes them well-suited for a wide variety of data acquisition and
signal processing applications.
The ADA4938-1 (single amplifier) is available in a Pb-free,
3 mm × 3 mm, 16-lead LFCSP. The ADA4938-2 (dual
amplifier) is available in a Pb-free, 4 mm × 4 mm, 24-lead
LFCSP. The pinouts have been optimized to facilitate layout and
minimize distortion. The devices are specified to operate over
the extended industrial temperature range of −40°C to +85°C.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 ©2007–2016 Analog Devices, Inc. All rights reserved.
Technical Support
www.analog.com
ADA4938-1/ADA4938-2
VOCM to ±OUT Performance
Table 4.
Parameter
VOCM DYNAMIC PERFORMANCE
−3 dB Bandwidth
Slew Rate
Input Voltage Noise (RTI)
VOCM INPUT CHARACTERISTICS
Input Voltage Range
Input Resistance
Input Offset Voltage
Input Bias Current
VOCM CMRR
Gain
POWER SUPPLY
Operating Range
Quiescent Current
Power Supply Rejection Ratio
POWER DOWN (PD)
PD Input Voltage
Turn-Off Time
Turn-On Time
PD Bias Current
Enabled
Disabled
OPERATING TEMPERATURE RANGE
Conditions
VIN = 1.6 V to 3.4 V, 25% to 75%
VOS, cm = VOUT, cm; VDIN+ = VDIN– = VOCM = 2.5 V
∆VOUT, dm/∆VOCM; ∆VOCM = ±1 V
∆VOUT, cm/∆VOCM; ∆VOCM = ±1 V
TMIN to TMAX variation
Powered down
∆VOUT, dm/∆VS; ∆VS = ±1 V
Powered down
Enabled
PD = 5 V
PD = 0 V
Data Sheet
Min Typ
400
1700
7.5
−VS + 1.3 to +VS − 1.3
10
3
0.5
−89
0.95 1.00
4.5
34
40
1.0
−80
≤2.5
≥3
1
200
1
−260
−40
Max Unit
MHz
V/µs
nV/√Hz
V
kΩ
mV
µA
dB
1.05 V/V
11 V
36.5 mA
µA/°C
1.7 mA
dB
V
V
µs
ns
µA
µA
+85 °C
Rev. B | Page 6 of 26
6 Page ADA4938-1/ADA4938-2
–40
HD2, VS = +5V
–50
HD3, VS = +5V
HD2, VS = ±5V
–60 HD3, VS = ±5V
–70
–80
–90
–100
–110
–120
1
10
FREQUENCY (MHz)
100
Figure 25. Harmonic Distortion vs. Frequency and Supply Voltage
–40
HD2, G = +1
–50
HD3, G = +1
HD2, G = +2
–60
HD3, G = +2
HD2, G = +5
–70 HD3, G = +5
–80
–90
–100
–110
–120
–130
1
10
FREQUENCY (MHz)
100
Figure 26. Harmonic Distortion vs. Frequency and Gain
–40
HD2, 10MHz
–50 HD3, 10MHz
HD2, 70MHz
–60 HD3, 70MHz
–70
–80
–90
–100
–110
–120
–130
–3.3 –2.7 –2.1 –1.5 –0.9 –0.3 0.3 0.9 1.5 2.1 2.7 3.3
VOCM (V)
Figure 27. Harmonic Distortion vs. VOCM and Frequency
Data Sheet
–40
HD2, +5V
HD3, +5V
–50 HD2, ±5V
HD3, ±5V
–60
–70
–80
–90
–100
–110
–120
0123456789
VOUT, dm (V)
Figure 28. Harmonic Distortion vs. VOUT and Supply Voltage
–40
HD2, RL = 1kΩ
–50
HD3, RL = 1kΩ
HD2, RL = 200Ω
HD3, RL = 200Ω
–60 HD2, RL = 100Ω
HD3, RL = 100Ω
–70
–80
–90
–100
–110
–120
1
10
FREQUENCY (MHz)
100
Figure 29. Harmonic Distortion vs. Frequency for Various Loads
–40
HD2, 10MHz
HD3, 10MHz
–50 HD2, 70MHz
HD3, 70MHz
–60
–70
–80
–90
–100
–110
–120
1.7 1.9 2.1 2.3 2.5 2.7 2.9 3.1 3.3
VOCM (V)
Figure 30. Harmonic Distortion vs. VOCM and Frequency, VS = 5 V
Rev. B | Page 12 of 26
12 Page | ||
Seiten | Gesamt 26 Seiten | |
PDF Download | [ ADA4938-1 Schematic.PDF ] |
Teilenummer | Beschreibung | Hersteller |
ADA4938-1 | Ultra-Low Distortion Differential ADC Driver | Analog Devices |
ADA4938-2 | Ultra-Low Distortion Differential ADC Driver | Analog Devices |
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