0.2 µV/°C Offset Drift, 105 MHz Low Power,
Low Noise, Rail-to-Rail Amplifiers
ADA4805-1/ADA4805-2
Data Sheet
FEATURES
TYPICAL APPLICATIONS CIRCUIT
+7.5V
Low input offset voltage: 125 µV (maximum)
Low input offset voltage drift
5V REF
ADA4805-1/
ADA4805-2
ADR435
VDD
0.2 µV/°C (typical)
1.5 µV/°C (maximum)
C4
100nF
C2
10µF
C3
0.1µF
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
+7.5V
ADA4805-1/
0V TO
REF
ADA4805-2
REF VDD
V
IN+
IN–
R3
20Ω
AD7980
GND
Settling time to 0.1%: 35 ns
Rail-to-rail outputs
C1
2.7nF
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
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.
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
0
INPUT FREQUENCY = 10kHz
SNR = 89.4dB
–20
THD = 104dB
SINAD = 89.3dB
–40
Photo multipliers
ADC reference buffers
–60
–80
GENERAL DESCRIPTION
–100
–120
–140
–160
–180
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).
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
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.
Throughput Resolution SNR
Product ADC Power (mW) (MSPS)
(Bits)
(dB)
AD7982
AD7984
AD7980
AD7685
7.0
10.5
4.0
10
1
1.33
1
18
18
16
16
98
98.5
91
0.25
88
Rev. B
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