Datasheet

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Low Noise, 1 GHz

FastFET

Op Amps

Data Sheet

ADA4817-1/ADA4817-2

Rev. B Document Feedback

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FEATURES

High speed

−3 dB bandwidth (G = 1, R

= 100 Ω): 1050 MHz

Slew rate: 870 V/µs

0.1% settling time: 9 ns

Low input bias current: 2 pA

Low input capacitance

Common-mode capacitance: 1.3 pF

Differential-mode capacitance: 0.1 pF

Low noise

4 nV/√Hz @ 100 kHz

2.5 fA/√Hz @ 100 kHz

Low distortion

−90 dBc @ 10 MHz (G = 1, R

= 1 kΩ)

Offset voltage: 2 mV maximum

High output current: 40 mA

Supply current per amplifier: 19 mA

Power-down supply current per amplifier: 1.5 mA

APPLICATIONS

Photodiode amplifiers

Data acquisition front ends

Instrumentation

Filters

ADC drivers

CCD output buffers

CONNECTION DIAGRAMS

NC = NO CONNECT

1PD

2FB

3–IN

+IN

7 OUT

8 +V

6 NC

–V

ADA4817-1

TOP VIEW

(Not to Scale)

07756-001

Figure 1. 8-Lead LFCSP (CP-8-2)

–IN

+IN

–V

OUT

NC = NO CONNECT

ADA4817-1

TOP VIEW

(Not to Scale)

07756-002

Figure 2. 8-Lead SOIC (RD-8-1)

07756-003

1–IN1

+IN1

4–V

12 –V

+IN2

9 –IN2

OUT2

PD2

FB2

FB1

OUT1

ADA4817-2

TOP VIEW

(Not to Scale)

NC = NO CONNECT

PD1

Figure 3. 16-Lead LFCSP (CP-16-20)

GENERAL DESCRIPTION

The ADA4817-1 (single) and ADA4817-2 (dual) FastFET™

amplifiers are unity-gain stable, ultrahigh speed voltage

feedback amplifiers with FET inputs. These amplifiers were

developed with the Analog Devices, Inc., proprietary eXtra Fast

Complementary Bipolar (XFCB) process, which allows the

amplifiers to achieve ultralow noise (4 nV/√Hz; 2.5 fA/√Hz)

as well as very high input impedances.

With 1.3 pF of input capacitance, low noise (4 nV/√Hz), low

offset voltage (2 mV maximum), and 1050 MHz −3 dB band-

width, the ADA4817-1/ADA4871-2 are ideal for data acquisition

front ends as well as wideband transimpedance applications,

such as photodiode preamps.

With a wide supply voltage range from 5 V to 10 V and the

ability to operate on either single or dual supplies, the

ADA4817-1/ ADA4817-2 are designed to work in a variety of

applications including active filtering and ADC driving.

The ADA4817-1 is available in a 3 mm × 3 mm, 8-lead LFCSP and

8-lead SOIC, and the ADA4817-2 is available in a 4 mm × 4 mm,

16-lead LFCSP. These packages feature a low distortion pinout

that improves second harmonic distortion and simplifies circuit

board layout. They also feature an exposed paddle that provides a

low thermal resistance path to the printed circuit board (PCB).

This enables more efficient heat transfer and increases reliability.

These products are rated to work over the extended industrial

temperature range (−40°C to +105°C).

Summary of content (28 pages)

PAGE 1
Low Noise, 1 GHz FastFET Op Amps ADA4817-1/ADA4817-2 Data Sheet CONNECTION DIAGRAMS ADA4817-1 TOP VIEW (Not to Scale) PD 1 8 +VS FB 2 7 OUT –IN 3 6 NC +IN 4 5 –VS 07756-001 High speed −3 dB bandwidth (G = 1, RL = 100 Ω): 1050 MHz Slew rate: 870 V/µs 0.1% settling time: 9 ns Low input bias current: 2 pA Low input capacitance Common-mode capacitance: 1.3 pF Differential-mode capacitance: 0.1 pF Low noise 4 nV/√Hz @ 100 kHz 2.
PAGE 2
ADA4817-1/ADA4817-2 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Driving Capacitive Loads .......................................................... 15 Applications ....................................................................................... 1 Thermal Considerations............................................................ 15 Connection Diagrams .......................................................
PAGE 3
Data Sheet ADA4817-1/ADA4817-2 SPECIFICATIONS ±5 V OPERATION TA = 25°C, +VS = 5 V, −VS = −5 V, G = 1, RF = 348 Ω for G > 1, RL = 100 Ω to ground, unless otherwise noted. Table 1. Parameter DYNAMIC PERFORMANCE −3 dB Bandwidth Gain Bandwidth Product Full Power Bandwidth 0.1 dB Flatness Slew Rate Settling Time to 0.
PAGE 4
ADA4817-1/ADA4817-2 Data Sheet 5 V OPERATION TA = 25°C, +VS = 3 V, −VS = −2 V, G = 1, RF = 348 Ω for G > 1, RL = 100 Ω to ground, unless otherwise noted. Table 2. Parameter DYNAMIC PERFORMANCE –3 dB Bandwidth Full Power Bandwidth 0.1 dB Flatness Slew Rate Settling Time to 0.
PAGE 5
Data Sheet ADA4817-1/ADA4817-2 ABSOLUTE MAXIMUM RATINGS PD = Quiescent Power + (Total Drive Power – Load Power) Table 3. Rating 10.6 V See Figure 4 −VS − 0.5 V to +VS + 0.5 V ±VS −65°C to +125°C −40°C to +105°C 300°C 150°C Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied.
PAGE 6
ADA4817-1/ADA4817-2 Data Sheet PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS ADA4817-1 PD 1 8 +VS FB 2 7 OUT –IN 3 6 NC +IN 4 5 –VS NC = NO CONNECT NOTES 1. EXPOSED PAD CAN BE CONNECTED TO GROUND PLANE OR NEGATIVE SUPPLY PLANE. 07756-005 TOP VIEW (Not to Scale) Figure 5. ADA4817-1 Pin Configuration (8-Lead LFCSP) Table 5. ADA4817-1 Pin Function Descriptions (8-Lead LFCSP) Pin No. 1 2 3 4 5 6 7 8 Mnemonic PD FB −IN +IN −VS NC OUT +VS Exposed pad (EPAD) Description Power-Down.
PAGE 7
Data Sheet ADA4817-1/ADA4817-2 ADA4817-2 –IN1 1 12 –VS1 +IN1 2 11 NC FB2 8 9 –IN2 PD2 7 10 +IN2 –VS2 4 OUT2 5 +VS2 6 NC 3 NC = NO CONNECT NOTES 1. EXPOSED PAD CAN BE CONNECTED TO THE GROUND PLANE OR NEGATIVE SUPPLY PLANE. 07756-107 14 +VS1 13 OUT1 16 FB1 15 PD1 TOP VIEW (Not to Scale) Figure 7. ADA4817-2 Pin Configuration (16-Lead LFCSP) Table 7. 16-Lead LFCSP Pin Function Descriptions Pin No.
PAGE 8
ADA4817-1/ADA4817-2 Data Sheet TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, VS = ±5 V, G = 1, (RF = 348 Ω for G > 1), RL = 100 Ω to ground, small signal VOUT = 100 mV p-p, large signal VOUT = 2 V p-p, unless noted otherwise. 6 G =2 0 G=5 –3 –6 –9 –12 100k 1M 10M 100M FREQUENCY (Hz) 1G 10G G=2 G = 1, SINGLE G = 1, DUAL 0 G=5 –3 –6 –9 –12 100k Figure 8.
PAGE 9
Data Sheet ADA4817-1/ADA4817-2 6 G = 2, SS 3 CLOSED-LOOP GAIN (dB) G = 2, LS 0.2 0.1 G = 1, SS 0 G = 1, LS –0.1 –0.2 –0.3 –3 –6 –9 –0.4 –0.5 100k 1M 10M 100M FREQUENCY (Hz) 1G 10G –12 100k –40 –40 –60 –60 DISTORTION (dBc) –20 –80 HD2, RL = 1kΩ –100 HD3, RL = 100Ω –120 10M 100M FREQUENCY (Hz) Figure 15. Distortion vs.
PAGE 10
ADA4817-1/ADA4817-2 0.15 DUAL, CF = 0.5pF SINGLE, NO CF 0.10 SINGLE OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 0.10 DUAL, CF = 0.5pF SINGLE, NO CF 0.05 0 –0.05 DUAL –0.10 SINGLE 0.05 0 –0.05 DUAL 07756-018 –0.10 G=2 –0.15 –0.15 07756-021 0.15 Data Sheet VS = 5V G=2 TIME (5ns/DIV) TIME (5ns/DIV) Figure 20. Small Signal Transient Response Figure 23. Small Signal Transient Response 1.5 0.075 1.0 0 –0.025 DUAL, LFCSP RF = 0Ω RL = 100Ω VS = ±5V G = +1 0 –0.5 –1.
PAGE 11
Data Sheet ADA4817-1/ADA4817-2 0.5 –10 0.4 –20 0.3 –40 –PSRR +PSRR –50 –60 –70 0.2 0.1 0 –0.1 –0.2 –80 –0.3 –90 –0.4 1M 10M 1G 100M FREQUENCY (Hz) –0.5 –40 07756-032 –100 100k 20 60 40 80 100 Figure 29. Offset Voltage vs. Temperature INPUT VOLTAGE NOISE (nV/ Hz) 1000 1M 10M 100M 1G FREQUENCY (Hz) 100 10 1 10 07756-029 CMRR (dB) 0 TEMPERATURE (°C) Figure 26. PSRR vs.
PAGE 12
ADA4817-1/ADA4817-2 VS = ±5V RL = 100Ω 1.5 –V-S + VOUT 700 NUMBER OF HITS 1.4 1.3 +VS – VOUT +VS – VOUT 1.2 1.1 1.0 500 400 300 0.8 –40 –20 0 20 40 60 100 80 0 –1.5 100 0 70 60 GAIN 40 PHASE –90 30 20 10 PHASE (Degrees) –45 50 –135 100M –180 1G FREQUENCY (Hz) 07756-015 0 10M –0.5 0 0.5 1.0 Figure 34. Input Offset Voltage Histogram Figure 32. Output Saturation Voltage vs. Temperature 1M –1.0 VOS (mV) TEMPERATURE (°C) 100k 07756-025 VS = +5V 0.
PAGE 13
Data Sheet ADA4817-1/ADA4817-2 TEST CIRCUITS The output feedback pins are used for ease of layout as shown in Figure 35 to Figure 40. +VS +VS 10µF + 10µF + RG 0.1µF RF 0.1µF 0.1µF 0.1µF VOUT VOUT VIN VIN RL 49.9Ω RL 49.9Ω 10µF + –VS –VS Figure 35. G = 1 Configuration Figure 38. Noninverting Gain Configuration +VS +VS 10µF + 49.9Ω AC 0.1µF 07756-147 0.1µF 07756-141 + 10µF 0.1µF VOUT VOUT RL 49.9Ω RL + 07756-145 0.1µF –VS 07756-148 AC 10µF –VS Figure 36.
PAGE 14
ADA4817-1/ADA4817-2 Data Sheet THEORY OF OPERATION The ADA4817-1/ADA4817-2 are voltage feedback operational amplifiers that combine new architecture for FET input operational amplifiers with the eXtra Fast Complementary Bipolar (XFCB) process from Analog Devices, resulting in an outstanding combination of speed and low noise. The innovative high speed FET input stage handles common-mode signals from the negative supply to within 2.7 V of the positive rail.
PAGE 15
Data Sheet ADA4817-1/ADA4817-2 VOS = VOS nom + Δ VS Δ VCM + PSR CMR (11) where: VOSnom is the offset voltage specified at nominal conditions. +VS 10µF + ΔVS is the change in power supply from nominal conditions. PSR is the power supply rejection. ΔVCM is the change in common-mode voltage from nominal conditions. CMR is the common-mode rejection. Note that such capacitance introduces significant peaking in the frequency response.
PAGE 16
ADA4817-1/ADA4817-2 Data Sheet Table 8. Power-Down Voltage Control PD Pin ±5 V +3 V, −2 V Not active Active >4 V <2 V >2 V <0 V Figure 47 shows the higher frequency attenuation, which reduces the peaking but also reduces the −3 dB bandwidth. 6 CAPACITIVE FEEDBACK RS = 75Ω CF = 0.5pF NO CF 0 RS = 100Ω –3 –9 RL = 100Ω VS = ±5V VOUT = 0.1V p-p G=1 1M 07756-247 –6 10M 100M FREQUENCY (Hz) 1G 10G Figure 47.
PAGE 17
Data Sheet ADA4817-1/ADA4817-2 LAYOUT, GROUNDING, AND BYPASSING CONSIDERATIONS Laying out the PCB is usually the last step in the design process and often proves to be one of the most critical. A brilliant design can be rendered useless because of poor layout. Because the ADA4817-1/ADA4817-2 can operate into the RF frequency spectrum, high frequency board layout considerations must be taken into account.
PAGE 18
ADA4817-1/ADA4817-2 Data Sheet LEAKAGE CURRENTS INPUT CAPACITANCE Poor PCB layout, contaminants, and the board insulator material can create leakage currents that are much larger than the input bias current of the ADA4817-1/ADA4817-2. Any voltage differential between the inputs and nearby runs sets up leakage currents through the PCB insulator, for example, 1 V/ 100 GΩ = 10 pA. Similarly, any contaminants, such as skin oils on the board, can create significant leakage.
PAGE 19
Data Sheet ADA4817-1/ADA4817-2 APPLICATIONS INFORMATION The ADA4817-1/ADA4817-2 feature a new low distortion pinout from Analog Devices. The new pinout provides two advantages over the traditional pinout. The first advantage is improved second harmonic distortion performance, which is accomplished by the physical separation of the noninverting input pin and the negative power supply pin.
PAGE 20
ADA4817-1/ADA4817-2 Data Sheet The loop transmission zero introduced by CF limits the amplification. The noise gain bandwidth extends past the preamp signal bandwidth and is eventually rolled off by the decreasing loop gain of the amplifier. The current equivalent noise from the inverting terminal is typically negligible for most applications. The innovative architecture used in the ADA4817-1/ADA4817-2 makes balancing both inputs unnecessary, as opposed to traditional FET input amplifiers.
PAGE 21
Data Sheet ADA4817-1/ADA4817-2 Common-mode rejection of the in-amp is primarily determined by the match of resistor ratios, R1:R2 to R3:R4. It can be estimated by HIGH SPEED JFET INPUT INSTRUMENTATION AMPLIFIER VO (δ1 − δ2 ) = VCM (1 + δ1) δ2 Figure 53 shows an example of a high speed instrumentation amplifier with a high input impedance using the ADA4817-1/ ADA4817-2.
PAGE 22
ADA4817-1/ADA4817-2 Data Sheet Resistor values are kept low for minimal noise contribution, offset voltage, and optimal frequency response. Due to the low capacitance values used in the filter circuit, the PCB layout and minimization of parasitics is critical. A few picofarads can detune the corner frequency, fc, of the filter. The capacitor values shown in Figure 55 actually incorporate some stray PCB capacitance.
PAGE 23
Data Sheet ADA4817-1/ADA4817-2 1.2 0.15 0.10 0.8 90MHz 90MHz 45MHz 45MHz 0.4 VOLTAGE (V) 0 0 –0.4 –0.05 –0.15 TIME (5ns/DIV) –1.2 TIME (5ns/DIV) Figure 57. Large Signal Transient Response (Low-Pass Filter) Figure 56. Small Signal Transient Response (Low-Pass Filter) Rev. B | Page 23 of 28 07756-064 –0.8 –0.10 07756-063 VOLTAGE (V) 0.
PAGE 24
ADA4817-1/ADA4817-2 Data Sheet OUTLINE DIMENSIONS 0.60 MAX 0.50 BSC 0.60 MAX 5 2.95 2.75 SQ 2.55 TOP VIEW PIN 1 INDICATOR 8 4 12° MAX 0.05 MAX 0.01 NOM 0.30 0.23 0.18 SEATING PLANE 1 0.50 0.40 0.30 0.70 MAX 0.65 TYP 0.90 MAX 0.85 NOM 1.60 1.45 1.30 EXPOSED PAD (BOTTOM VIEW) 1.89 1.74 1.59 PIN 1 INDICATOR FOR PROPER CONNECTION OF THE EXPOSED PAD, REFER TO THE PIN CONFIGURATION AND FUNCTION DESCRIPTIONS SECTION OF THIS DATA SHEET. 0.20 REF 04-04-2012-A 3.25 3.00 SQ 2.75 Figure 58.
PAGE 25
Data Sheet ADA4817-1/ADA4817-2 0.35 0.30 0.25 0.65 BSC PIN 1 INDICATOR 16 13 1 12 EXPOSED PAD 2.40 2.35 SQ 2.30 9 TOP VIEW 0.80 0.75 0.70 0.50 0.40 0.30 4 8 0.25 MIN BOTTOM VIEW 0.05 MAX 0.02 NOM COPLANARITY 0.08 0.20 REF SEATING PLANE 5 FOR PROPER CONNECTION OF THE EXPOSED PAD, REFER TO THE PIN CONFIGURATION AND FUNCTION DESCRIPTIONS SECTION OF THIS DATA SHEET. 07-18-2012-B PIN 1 INDICATOR 4.10 4.00 SQ 3.90 COMPLIANT TO JEDEC STANDARDS MO-220-WGGC-3. Figure 60.
PAGE 26
ADA4817-1/ADA4817-2 Data Sheet NOTES Rev.
PAGE 27
Data Sheet ADA4817-1/ADA4817-2 NOTES Rev.
PAGE 28
ADA4817-1/ADA4817-2 Data Sheet NOTES ©2008–2013 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D07756-0-5/13(B) Rev.