ADA4805-1 Datasheet, PDF (1/25 Pages) Analog Devices – 0.2 μV/°C Offset Drift, 105 MHz Low Power, Low Noise, Rail-to-Rail Amplifiers

Data Sheet
0.2 µV/°C Offset Drift, 105 MHz Low Power,
Low Noise, Rail-to-Rail Amplifiers
ADA4805-1/ADA4805-2
FEATURES
Low input offset voltage: 125 µV (maximum)
Low input offset voltage drift
0.2 µV/°C (typical)
1.5 µV/°C (maximum)
Ultralow supply current: 500 µA per amplifier
Fully specified at VS = 3 V, 5 V, ±5 V
High speed performance
−3 dB bandwidth: 105 MHz
Slew rate: 160 V/µs
Settling time to 0.1%: 35 ns
Rail-to-rail outputs
Input common-mode range: −VS − 0.1 V to +VS − 1 V
Low noise: 5.9 nV/√Hz at 100 kHz; 0.6 pA/√Hz at 100 kHz
Low distortion: −102 dBc/−126 dBc HD2/HD3 at 100 kHz
Low input bias current: 470 nA (typical)
Dynamic power scaling
Turn-on time: 3 µs (maximum) fully settled
Small packaging
6-lead SC70, 6-lead SOT-23, and 8-lead MSOP
APPLICATIONS
High resolution, high precision analog-to-digital converter
(ADC) drivers
Battery-powered instrumentation
Micropower active filters
Portable point of sales terminals
Active RFID readers
Photo multipliers
ADC reference buffers
GENERAL DESCRIPTION
The ADA4805-1/ADA4805-2 are high speed voltage feedback,
rail-to-rail output amplifiers with an exceptionally low
quiescent current of 500 µA, making them ideal for low power,
high resolution data conversion systems. Despite being low
power, these amplifiers provide excellent overall performance.
They offer a high bandwidth of 105 MHz at a gain of +1, a high
slew rate of 160 V/µs, and a low input offset voltage of 125 µV
(maximum).
A shutdown pin allows further reduction of the quiescent
supply current to 2.9 µA. For power sensitive applications, the
shutdown mode offers a very fast turn-on time of 3 µs. This
allows the user to dynamically manage the power of the
amplifier by turning the amplifier off between ADC samples.
TYPICAL APPLICATIONS CIRCUIT
5V REF
ADR435
+7.5V
ADA4805-1/
ADA4805-2
C2
10µF
C3
0.1µF
C4
100nF
VDD
0V TO
V_REF
+7.5V
ADA4805-1/
ADA4805-2
R3
20Ω
C1
2.7nF
REF VDD
IN+
AD7980
IN–
GND
Figure 1. Driving the AD7980 with the ADA4805-1/ADA4805-2
The Analog Devices, Inc., proprietary extra fast complementary
bipolar (XFCB) process allows both low voltage and low current
noise (5.9 nV/√Hz, 0.6 pA/√Hz). The ADA4805-1/ADA4805-2
operate over a wide range of supply voltages from ±1.5 V to
±5 V, as well as single 3 V and 5 V supplies, making them ideal
for high speed, low power instruments.
The ADA4805-1 is available in a 6-lead SOT-23 and a 6-lead
SC70 package. The ADA4805-2 is available in an 8-lead MSOP
and a 10-lead LFCSP package. These amplifiers are rated to
work over the industrial temperature range of −40°C to +125°C.
0
INPUT FREQUENCY = 10kHz
–20
SNR = 89.4dB
THD = 104dB
SINAD = 89.3dB
–40
–60
–80
–100
–120
–140
–160
–180
0
10
20
30
40
50
60
70
80
FREQUENCY (kHz)
Figure 2. FFT Plot for the Circuit Configuration in Figure 1
Table 1. Complementary ADCs to the ADA4805-1/ADA4805-2
Throughput Resolution SNR
Product ADC Power (mW) (MSPS)
(Bits)
(dB)
AD7982 7.0
1
18
98
AD7984 10.5
1.33
18
98.5
AD7980 4.0
1
16
91
AD7685 10
0.25
16
88
Rev. B
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