Datasheet

ManualsBrandsANALOG DEVICES ManualsLinear ICsLinear IC - Op-amp Voltage feedback SOIC 8

Ultralow Distortion, Low Power,

Low Noise, High Speed Op Amp

Data Sheet

ADA4857-1/ADA4857-2

Rev. C Document Feedback

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FEATURES

High speed

850 MHz, −3 dB bandwidth (G = +1, R

= 1 kΩ, LFCSP)

750 MHz, −3 dB bandwidth (G = +1, R

= 1 kΩ, SOIC)

2800 V/µs slew rate

Low distortion: −88 dBc at 10 MHz (G = +1, R

= 1 kΩ)

Low power: 5 mA/amplifier at 10 V

Low noise: 4.4 nV/√Hz

Wide supply voltage range: 5 V to 10 V

Power-down feature

Available in 3 mm × 3 mm 8-lead LFCSP (single), 8-lead SOIC

(single), and 4 mm × 4 mm 16-lead LFCSP (dual)

APPLICATIONS

Instrumentation

IF and baseband amplifiers

Active filters

ADC drivers

DAC buffers

CONNECTION DIAGRAMS

1PD

–IN

+IN

7 OUT

5 –V

ADA4857-1

TOP VIEW

(Not to Scale)

07040-001

NOTES

1. NC = NO CONNECT. DO NOT CONNECT

TO THIS PIN.

2. THE EXPOSED

PAD M

Y BE CONNECTED

O GND OR VS.

Figure 1. 8-Lead LFCSP (CP)

–IN

+IN

–V

OUT

NC = NO CONNECT

ADA4857-1

TOP VIEW

(Not to Scale)

07040-002

Figure 2. 8-Lead SOIC (R)

ADA4857-2

TOP VIEW

(Not to Scale)

07040-003

NOTES

1. NC = NO CONNECT. DO NOT CONNECT

TO THIS PIN.

2. THE EXPOSED PAD MAY BE CONNECTED

TO GND OR VS.

–IN1

+IN1

–V

OUT1

PD1

FB1

+IN2

–IN2

OUT2

PD2

FB2

Figure 3. 16-Lead LFCSP (CP)

GENERAL DESCRIPTION

The ADA4857 is a unity-gain stable, high speed, voltage feedback

amplifier with low distortion, low noise, and high slew rate. With a

spurious-free dynamic range (SFDR) of −88 dBc at 10 MHz, the

ADA4857 is an ideal solution for a variety of applications, including

ultrasounds, ATE, active filters, and ADC drivers. The Analog

Devices, Inc., proprietary next-generation XFCB process and

innovative architecture enables such high performance amplifiers.

The ADA4857 has 850 MHz bandwidth, 2800 V/µs slew rate, and

settles to 0.1% in 15 ns. With a wide supply voltage range (5 V to

10 V), the ADA4857 is an ideal candidate for systems that require

high dynamic range, precision, and speed.

The ADA4857-1 amplifier is available in a 3 mm × 3 mm, 8-lead

LFCSP and a standard 8-lead SOIC. The ADA4857-2 is available in

a 4 mm × 4 mm, 16-lead LFCSP. The LFCSP features an exposed

paddle that provides a low thermal resistance path to the printed

circuit board (PCB). This path enables more efficient heat transfer

and increases reliability. The ADA4857 works over the extended

industrial temperature range (−40°C to +125°C).

Summary of content (20 pages)

PAGE 1
Ultralow Distortion, Low Power, Low Noise, High Speed Op Amp ADA4857-1/ADA4857-2 Data Sheet CONNECTION DIAGRAMS High speed 850 MHz, −3 dB bandwidth (G = +1, RL = 1 kΩ, LFCSP) 750 MHz, −3 dB bandwidth (G = +1, RL = 1 kΩ, SOIC) 2800 V/µs slew rate Low distortion: −88 dBc at 10 MHz (G = +1, RL = 1 kΩ) Low power: 5 mA/amplifier at 10 V Low noise: 4.
PAGE 2
ADA4857-1/ADA4857-2 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Test Circuits..................................................................................... 15 Applications ....................................................................................... 1 Applications Information .............................................................. 16 Connection Diagrams ...................................
PAGE 3
Data Sheet ADA4857-1/ADA4857-2 SPECIFICATIONS ±5 V SUPPLY TA = 25°C, G = +2, RG = RF = 499 Ω, RS = 100 Ω for G = +1 (SOIC), RL = 1 kΩ to ground, PD = no connect, unless otherwise noted. Table 1. Parameter DYNAMIC PERFORMANCE –3 dB Bandwidth (LFCSP/SOIC) Full Power Bandwidth Bandwidth for 0.1 dB Flatness (LFCSP/SOIC) Slew Rate (10% to 90%) Settling Time to 0.
PAGE 4
ADA4857-1/ADA4857-2 Parameter POWER SUPPLY Operating Range Quiescent Current Quiescent Current (Power Down) Positive Power Supply Rejection Negative Power Supply Rejection Data Sheet Conditions Min Typ 4.5 PD ≥ VCC − 2 V +VS = 4.5 V to 5.5 V, −VS = −5 V +VS = 5 V, −VS = −4.5 V to −5.5 V −59 −65 5 350 −62 −68 Max Unit 10.5 5.5 450 V mA µA dB dB +5 V SUPPLY TA = 25°C, G = +2, RF = RG = 499 Ω, RS = 100 Ω for G = +1 (SOIC), RL = 1 kΩ to midsupply, PD = no connect, unless otherwise noted. Table 2.
PAGE 5
Data Sheet Parameter OUTPUT CHARACTERISTICS Overdrive Recovery Time Output Voltage Swing Output Current Short-Circuit Current Capacitive Load Drive POWER SUPPLY Operating Range Quiescent Current Quiescent Current (Power Down) Positive Power Supply Rejection Negative Power Supply Rejection ADA4857-1/ADA4857-2 Conditions Min G = +2 RL = 1 kΩ RL = 100 Ω Typ 15 1 to 4 1.1 to 3.9 50 75 10 Sinking and sourcing 30% overshoot, G = +2 4.5 PD ≥ VCC − 2 V +VS = 4.5 V to 5.5 V, −VS = 0 V +VS = 5 V, −VS = −0.
PAGE 6
ADA4857-1/ADA4857-2 Data Sheet ABSOLUTE MAXIMUM RATINGS Table 3. Rating 11 V See Figure 4 −VS + 0.7 V to +VS − 0.7 V ±VS −VS −65°C to +125°C −40°C to +125°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 7
Data Sheet ADA4857-1/ADA4857-2 FB 1 PD 1 FB 2 ADA4857-1 8 +VS 7 OUT –IN 3 TOP VIEW (Not to Scale) 6 NC +IN 4 –IN 2 ADA4857-1 8 PD 7 +VS TOP VIEW +IN 3 (Not to Scale) 6 OUT 5 NC –VS 4 5 –VS 07040-005 NC = NO CONNECT NOTES 1. NC = NO CONNECT. DO NOT CONNECT TO THIS PIN. 2. THE EXPOSED PAD MAY BE CONNECTED TO GND OR VS. 07040-006 PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS Figure 6. 8-Lead SOIC Pin Configuration Figure 5. 8-Lead LFCSP Pin Configuration Table 5.
PAGE 8
13 OUT1 14 +VS1 16 FB1 Data Sheet 15 PD1 ADA4857-1/ADA4857-2 –IN1 1 NC 3 12 –VS1 ADA4857-2 11 NC TOP VIEW (Not to Scale) 10 +IN2 9 –IN2 FB2 8 PD2 7 +VS2 6 OUT2 5 –VS2 4 NOTES 1. NC = NO CONNECT. DO NOT CONNECT TO THIS PIN. 2. THE EXPOSED PAD MAY BE CONNECTED TO GND OR VS. 07040-007 +IN1 2 Figure 7. 16-Lead LFCSP Pin Configuration Table 7. 16-Lead LFCSP Pin Function Descriptions Pin No.
PAGE 9
Data Sheet ADA4857-1/ADA4857-2 TYPICAL PERFORMANCE CHARACTERISTICS 3 2 2 G = +2 –2 –3 –4 G = +10 –5 –6 G = +5 –7 –8 VS = ±5V RL = 1kΩ VOUT = 0.2V p-p –9 –10 1 10 100 1000 G = +10 –5 G = +5 –6 –7 –8 VS = ±5V RL = 1kΩ VOUT = 2V p-p CLOSED-LOOP GAIN (dB) 0 –1 –2 ±5V –3 –4 –5 –6 +5V –7 10 100 1000 FREQUENCY (MHz) 07040-009 G = +1 RL = 1kΩ VOUT = 0.2V p-p –10 9 8 7 6 5 4 3 2 1 0 –1 –2 –3 –4 –5 –6 –7 5pF NO CAP LOAD G = +2 VS = ±5V RL = 1kΩ VOUT = 0.
PAGE 10
Data Sheet 3 9 8 7 6 5 4 3 2 1 0 –1 –2 –3 –4 –5 –6 –7 2 RL = 1kΩ CLOSED-LOOP GAIN (dB) 1 RL = 100Ω 10 100 1000 RL = 100Ω –3 –4 –5 –6 –7 G = +1 VS = ±5V VOUT = 2V p-p –10 1 10 100 1000 FREQUENCY (MHz) Figure 14. Small Signal Frequency Response for Various Resistive Loads (LFCSP) Figure 17. Large Signal Frequency Response for Various Resistive Loads (LFCSP) 3 3 2 1 G = +1 0 –1 G = +2 –2 –3 –4 G = +10 –5 –6 G = +5 –7 VS = 5V RL = 1kΩ VOUT = 0.
PAGE 11
Data Sheet –40 ADA4857-1/ADA4857-2 0.5 G = +2 VS = ±5V RL= 1kΩ –50 VOUT = 2V p-p G = +2 VS = ±5 0.4 HD3, f = 10MHz 0.3 HD2, f = 10MHz SETTLING TIME (%) –70 –80 –90 HD3, f = 1MHz HD2, f = 1MHz 0.1 OUTPUT 0 –0.1 –0.2 –0.3 –110 INPUT 07040-023 –100 0.2 –0.4 1 2 3 4 5 6 7 OUTPUT VOLTAGE (V p-p) 8 –0.5 07040-020 –120 TIME (5ns/DIV) Figure 20. Harmonic Distortion vs. Output Voltage 6.3 Figure 23. Short-Term Settling Time (LFCSP) 6.3 VS = ±5V G = +2 RL= 150Ω 6.
PAGE 12
ADA4857-1/ADA4857-2 Data Sheet 2.0 0.25 VS = ±5V RL = 1kΩ G = +1 0.20 1.2 0.10 CL = 1.5pF 0.05 0 –0.05 –0.10 0.8 RL = 1kΩ 0.4 0 –0.4 –0.8 –1.2 CL = 10pF –0.20 –0.25 07040-026 –0.15 RL = 100Ω –1.6 –2.0 TIME (10ns/DIV) TIME (10ns/DIV) Figure 26. Small Signal Transient Response for Various Capacitive Loads (LFCSP) Figure 29. Large Signal Transient Response for Various Load Resistances (SOIC) 2.0 0.25 RL = 1kΩ G = +1 0.20 1.6 RL = 1kΩ VS = ±2.5V 0 –0.05 –0.10 0.8 0.4 0 –0.4 –0.8 –1.
PAGE 13
Data Sheet ADA4857-1/ADA4857-2 –60 40 –80 30 –100 20 –120 10 –140 0 –160 1 10 FREQUENCY (MHz) –30 –40 –50 LFCSP –60 –70 –80 –100 0.1 1 1000 8 VS = ±5V G = +1 6 VS = ±5V G = +2 6 4 OUTPUT VOLTAGE (V) 4 2 0 OUTPUT RL = 100Ω –2 –4 2 0 –2 –4 OUTPUT RL = 100Ω 07040-036 INPUT –8 OUTPUT RL = 1kΩ 2 × INPUT –6 07040-033 OUTPUT RL = 1kΩ –6 –8 TIME (40ns/DIV) TIME (200ns/DIV) Figure 33. Input Overdrive Recovery for Various Resistive Loads 0 100 Figure 35. PD Isolation vs.
PAGE 14
ADA4857-1/ADA4857-2 Data Sheet 1000 VS = ±5V VOLTAGE NOISE (nV/√Hz) 10 1 10 100 1k 10k 100k 1M FREQUENCY (Hz) 100 10 1 07040-050 1 100 1k 10k 100k FREQUENCY (Hz) 1M Figure 40. Input Voltage Noise vs. Frequency Figure 38. Input Current Noise vs. Frequency 3.5 50 N = 238 MEAN: 5.00 SD: 0.02 3.0 40 VOLTAGE (V) 2.5 30 20 PD INPUT 2.0 1.5 1.0 0.5 OUTPUT 10 0 0 4.85 4.90 4.95 5.00 5.05 SUPPLY CURRENT (mA) 5.10 5.15 07040-042 COUNT 10 Figure 39.
PAGE 15
Data Sheet ADA4857-1/ADA4857-2 TEST CIRCUITS +VS 10µF +VS + 10µF + 1kΩ 0.1µF 0.1µF VIN VOUT RS RL 49.9Ω 0.1µF 1kΩ 53.6Ω VOUT RL 1kΩ 10µF + + 10µF –VS –VS Figure 42. Noninverting Load Configuration Figure 45. Common-Mode Rejection +VS +VS 10µF + 49.9Ω AC 0.1µF 07040-047 0.1µF 07040-046 VIN 0.1µF 1kΩ 0.1µF VOUT VOUT RL 49.9Ω AC 07040-045 0.1µF –VS –VS Figure 43. Positive Power Supply Rejection 10µF 07040-048 + 10µF RL Figure 46.
PAGE 16
ADA4857-1/ADA4857-2 Data Sheet APPLICATIONS INFORMATION POWER-DOWN OPERATION CAPACITIVE LOAD CONSIDERATIONS The PD pin is used to power down the chip, which reduces the quiescent current and the overall power consumption. It is low enabled, which means that the chip is on with full power when the PD pin input voltage is low (see Table 8). Note that PD does not put the output in a high-Z state, which means that the ADA4857 should not be used as a multiplexer.
PAGE 17
Data Sheet ADA4857-1/ADA4857-2 ACTIVE LOW-PASS FILTER (LPF) Figure 48 shows the output of each stage is of the filter and the two different filters corresponding to R = 182 Ω and R = 365 Ω. 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.
PAGE 18
ADA4857-1/ADA4857-2 Data Sheet NOISE CIRCUIT CONSIDERATIONS To analyze the noise performance of an amplifier circuit, identify the noise sources and determine if the source has a significant contribution to the overall noise performance of the amplifier.
PAGE 19
Data Sheet ADA4857-1/ADA4857-2 OUTLINE DIMENSIONS 0.60 MAX 5 2.95 2.75 SQ 2.55 TOP VIEW PIN 1 INDICATOR 8 12° MAX 0.50 0.40 0.30 0.70 MAX 0.65 TYP 0.05 MAX 0.01 NOM 0.30 0.23 0.18 SEATING PLANE 1.60 1.45 1.30 EXPOSED PAD (BOTTOM VIEW) 4 0.90 MAX 0.85 NOM 0.50 BSC 0.60 MAX 0.20 REF 1 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. 04-04-2012-A 3.25 3.00 SQ 2.75 Figure 51.
PAGE 20
ADA4857-1/ADA4857-2 4.10 4.00 SQ 3.90 0.35 0.30 0.25 0.65 BSC PIN 1 INDICATOR 16 13 1 12 EXPOSED PAD 2.25 2.10 SQ 1.95 9 TOP VIEW 0.80 0.75 0.70 0.70 0.60 0.50 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. 111908-A PIN 1 INDICATOR Data Sheet COMPLIANT TO JEDEC STANDARDS MO-220-WGGC. Figure 53.