0.2 µV/°C Offset Drift, 105 MHz Low Power,

Low Noise, Rail-to-Rail Amplifiers

Data Sheet

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

High speed performance

−3 dB bandwidth: 105 MHz

Slew rate: 160 V/µs

Settling time to 0.1%: 35 ns

Rail-to-rail outputs

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

AD7980

C2

10µF

IN+

IN–

GND

VDD

REF

C3

0.1µF

C4

100nF

VDD

C1

2.7nF

R3

20Ω

+7.5V

+7.5V

ADA4805-1/

ADA4805-2

ADA4805-1/

ADA4805-2

ADR435

5V REF

0V TO

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

80

20

40

60

70

50

30

10

FREQUENCY (kHz)

–20

0

–40

–60

–80

–100

–120

–140

–160

–180

INPUT FREQUENCY = 10kHz

SNR = 89.4dB

THD = 104dB

SINAD = 89.3dB

Figure 2. FFT Plot for the Circuit Configuration in Figure 1

Product

ADC Power (mW)

Throughput

(MSPS)

Resolution

(Bits)

SNR

(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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