Datasheet

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Precision Low Power

Single-Supply JFET Amplifiers

Data Sheet

AD8625/AD8626/AD8627

Rev. F Document Feedback

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FEATURES

SC70 package

Very low I

: 1 pA max

Single-supply operation: 5 V to 26 V

Dual-supply operation: ±2.5 V to ±13 V

Rail-to-rail output

Low supply current: 630 μA/amp typ

Low offset voltage: 500 μV max

Unity gain stable

No phase reversal

APPLICATIONS

Photodiode amplifiers

ATE s

Line-powered/battery-powered instrumentation

Industrial controls

Automotive sensors

Precision filters

Audio

PIN CONFIGURATIONS

03023-001

5OUT A

V–

+IN

V+

–IN

AD8627

5-Lead SC70

(KS Suffix)

–IN V+

+IN OUT

V– NC

AD8627

NC = NO CONNECT

8-Lead SOIC

(R-8 Suffix)

OUT A

–IN A OUT B

+IN A –IN B

V– +IN B

V+

AD8626

8-Lead SOIC

(R-8 Suffix)

V+OUT A

OUT B–IN A

–IN B+IN A

+IN BV–

AD8626

8-Lead MSOP

(RM-Suffix)

OUT A OUT D

114

–IN A –IN D

213

+IN A +IN D

312

V+ V–

411

+IN B +IN C

510

–IN B –IN C

OUT B OUT C

AD8625

14-Lead SOIC

(R-Suffix)

OUT DOUT A

–IN D–IN A

+IN D+IN A

V–V+

+IN C+IN B

–IN C–IN B

OUT COUT B

AD8625

14-Lead TSSOP

(RU-Suffix)

Figure 1.

GENERAL DESCRIPTION

The AD862x is a precision JFET input amplifier. It features

true single-supply operation, low power consumption, and

rail-to-rail output. The outputs remain stable with capacitive

loads of over 500 pF; the supply current is less than 630 μA/amp.

Applications for the AD862x include photodiode transimpedance

amplification, ATE reference level drivers, battery management,

both line powered and portable instrumentation, and remote

sensor signal conditioning, which includes automotive sensors.

The AD862x’s ability to swing nearly rail-to-rail at the input

and rail-to-rail at the output enables it to be used to buffer

CMOS DACs, ASICs, and other wide output swing devices in

single-supply systems.

The 5 MHz bandwidth and low offset are ideal for precision filters.

The AD862x is fully specified over the industrial temperature

range. (−40°C to +85°C). e AD8627 is available in both

5-lead SC70 and 8-lead SOIC surface-mount packages (SC70

packaged parts are available in tape and reel only). The AD8626

is available in MSOP and SOIC packages, while the AD8625 is

available in TSSOP and SOIC packages.

Summary of content (20 pages)

PAGE 1
Precision Low Power Single-Supply JFET Amplifiers AD8625/AD8626/AD8627 Data Sheet FEATURES PIN CONFIGURATIONS 8-Lead SOIC (R-8 Suffix) SC70 package Very low IB: 1 pA max Single-supply operation: 5 V to 26 V Dual-supply operation: ±2.
PAGE 2
AD8625/AD8626/AD8627 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Typical Performance Characteristics ..............................................6 Applications ....................................................................................... 1 Applications Information .............................................................. 13 Pin Configurations .....................................................
PAGE 3
Data Sheet AD8625/AD8626/AD8627 SPECIFICATIONS ELECTRICAL CHARACTERISTICS @VS = 5 V, VCM = 1.5 V, TA = 25°C, unless otherwise noted. Table 1. Parameter INPUT CHARACTERISTICS Offset Voltage Symbol Conditions Min VOS Typ Max Unit 0.05 0.5 1.2 1 60 0.5 25 3 87 230 2.5 mV mV pA pA pA pA V dB V/mV µV/°C ±10 V V V V mA −40°C < TA < +85°C Input Bias Current IB 0.
PAGE 4
AD8625/AD8626/AD8627 Data Sheet @VS = ±13 V; VCM = 0 V; TA = 25°C, unless otherwise noted. Table 2. Parameter INPUT CHARACTERISTICS Offset Voltage Symbol Conditions Min VOS Typ Max Unit 0.35 0.75 1.35 1 60 0.5 25 +11 105 310 2.5 mV mV pA pA pA pA V dB V/mV µV/°C ±15 V V V V mA –40°C < TA < +85°C Input Bias Current IB 0.
PAGE 5
Data Sheet AD8625/AD8626/AD8627 ABSOLUTE MAXIMUM RATINGS Table 3.
PAGE 6
AD8625/AD8626/AD8627 Data Sheet TYPICAL PERFORMANCE CHARACTERISTICS 16 VSY = ±12V TA = 25°C VSY = +3.5V/–1.5V 14 20 NUMBER OF AMPLIFIERS NUMBER OF AMPLIFIERS 25 15 10 12 10 8 6 4 5 –600 –400 –200 0 200 400 0 600 03023-005 03023-002 0 1 2 Figure 2. Input Offset Voltage 50 VSY = ±13V 40 6 7 8 9 10 VSY = ±13V TA = 25°C 6 4 03023-003 0 1 2 3 4 5 6 7 8 9 20 10 0 –10 –20 –30 03023-006 8 2 –40 –50 –15.0–12.5–10.0 –7.5 –5.0 –2.5 0 2.
PAGE 7
Data Sheet AD8625/AD8626/AD8627 100 500 VSY = 5V 10 1 0.1 –50 125 100 50 75 25 TEMPERATURE (°C) 0 –25 300 200 100 0 –100 –200 –300 03023-011 INPUT OFFSET VOLTAGE (µV) 400 03023-008 INPUT BIAS CURRENT (pA) VSY = ±13V VCM = 0V –400 –500 –1 150 0 1 2 3 4 VCM (V) Figure 8. Input Bias Current vs. Temperature Figure 11. Input Offset Voltage vs. VCM 10M 2.0 VSY = +5V OR ±5V 0.5 0 –0.5 –1.0 –4 –3 –2 –1 0 1 2 3 4 VSY = ±13V VSY = +5V 100k 10k 0.
PAGE 8
AD8625/AD8626/AD8627 10k VSY = ±13V VSY = ±13V OFFSET VOLTAGE (µV) 400 VSY – OUTPUT VOLTAGE (mV) 500 RL = 10kΩ 300 200 RL = 100kΩ 100 0 RL = 600Ω –100 100 VOL 10 03023-014 –200 1k –300 –400 –15 –10 –5 0 5 OUTPUT VOLTAGE (V) 10 1 0.001 15 Figure 14. Input Error Voltage vs. Output Voltage for Resistive Loads 250 RL = 1kΩ 200 VOH 03023-017 600 Data Sheet 0.01 0.1 1 LOAD CURRENT (mA) 10 100 Figure 17. Output Saturation Voltage vs.
PAGE 9
Data Sheet AD8625/AD8626/AD8627 140 50 315 VSY = 5V RL = 2kΩ 270 CL = 40pF 225 40 180 80 135 20 90 PHASE 45 0 –0 –45 –20 –90 100k 1M FREQUENCY (Hz) –135 50M 10M 40 20 0 –10 –30 10k 60 –20 03023-023 10 100 CMRR (dB) 30 –40 –60 1k 10k Figure 20. Open-Loop Gain and Phase Margin vs. Frequency 100k FREQUENCY (Hz) 1M 10M Figure 23. CMRR vs.
PAGE 10
AD8625/AD8626/AD8627 Data Sheet 140 VSY = ±13V INPUT VSY = 5V 120 100 VOLTAGE (10V/DIV) PSRR (dB) 80 60 40 +PSRR 20 –PSRR OUTPUT 0 03023-026 03023-029 –20 –40 –60 1k 10k 100k FREQUENCY (Hz) 1M TIME (400µs/DIV) 10M Figure 29. No Phase Reversal Figure 26. PSRR vs. Frequency 270 15 VSY = ±13V 10 240 TS + (1%) OUTPUT SWING (V) 180 150 120 90 G = +10 0 TS – (0.1%) –5 TS – (1%) –10 03023-027 G = +100 30 10k TS + (0.1%) G = +1 60 0 1k 5 100k 1M FREQUENCY (Hz) 10M –15 1.5 1.
PAGE 11
Data Sheet AD8625/AD8626/AD8627 56 70 VS = ±2.5V RL = 10kΩ 60 VIN = 100mV p-p AV = +1 42 VOLTAGE (nV) 50 OVERSHOOT (%) VSY = ±13V 49 40 30 35 19.7nV/ Hz 28 21 OS+ 20 14 OS– 0 10 100 CAPACITANCE (pF) 03023-035 7 03023-032 10 0 0 1k 1 Figure 32. Small-Signal Overshoot vs. Load Capacitance 2 3 4 5 6 FREQUENCY (kHz) 7 8 9 10 8 9 10 Figure 35. Voltage Noise Density 56 VSY = ±13V AVO = 100,000V/V VSY = 5V 42 VOLTAGE (nV) VOLTAGE (50mV/DIV) 49 0 35 16.
PAGE 12
AD8625/AD8626/AD8627 Data Sheet 20kΩ 2kΩ VIN 2kΩ 2kΩ –80 –100 VIN = 9V p-p VIN = 4.5V p-p VIN = 18V p-p –110 –120 –130 –140 –150 –160 10 03023-049 CHANNEL SEPARATION (dB) –90 100 1k 10k FREQUENCY (Hz) 100k Figure 38. Channel Separation Rev.
PAGE 13
Data Sheet AD8625/AD8626/AD8627 APPLICATIONS INFORMATION INPUT VOLTAGE (2V/DIV) 4V 0V 4V OUTPUT 03023-038 0V TIME (2µs/DIV) Figure 39. Unity Gain Follower Response to 0 V to 4 V Step VSY = 5V 5V INPUT 0V 4V OUTPUT 0V 03023-039 The AD862x does not experience phase reversal with input signals close to the positive rail, as shown in Figure 29.
PAGE 14
AD8625/AD8626/AD8627 Data Sheet 20kΩ The AD862x can safely withstand input voltages 15 V below VSY if the total voltage between the positive supply and the input terminal is less than 26 V. Figure 41 through Figure 43 show the AD862x in different configurations accommodating signals close to the negative rail. The amplifier input stage typically maintains picoamp-level input currents across that input voltage range. 10kΩ +5V 0V –10mV –30mV VSY = 5V 20kΩ +5V VOLTAGE (10mV/DIV) 10kΩ 0V –2.
PAGE 15
Data Sheet AD8625/AD8626/AD8627 MINIMIZING INPUT CURRENT PHOTODIODE PREAMPLIFIER APPLICATION The AD862x is guaranteed to 1 pA maximum input current with a ±13 V supply voltage at room temperature. Careful attention to how the amplifier is used maintains or possibly betters this performance. The amplifier’s operating temperature should be kept as low as possible. Like other JFET input amplifiers, the AD862x’s input current doubles for every 10°C rise in junction temperature, as illustrated in Figure 8.
PAGE 16
AD8625/AD8626/AD8627 Data Sheet OUTPUT AMPLIFIER FOR DACs 2.5V 5V 10µF 0.1µF 0.1µF 5V SERIAL INTERFACE VREFS * VREFF* VDD CS DIN SCLK AD8627 AD5551/AD5552 UNIPOLAR OUTPUT OUT 03023-045 LDAC* AGND DGND *AD5552 ONLY Figure 46.
PAGE 17
Data Sheet AD8625/AD8626/AD8627 EIGHT-POLE SALLEN KEY LOW-PASS FILTER 1.2 The AD862x’s high input impedance and dc precision make it a great selection for active filters. Due to the very low bias current of the AD862x, high value resistors can be used to construct low frequency filters. The AD862x’s picoamp-level input currents contribute minimal dc errors. Figure 49 shows an example of a 10 Hz, 8-pole Sallen Key filter constructed using the AD862x.
PAGE 18
AD8625/AD8626/AD8627 Data Sheet OUTLINE DIMENSIONS 2.20 2.00 1.80 1.35 1.25 1.15 5 2.40 2.10 1.80 4 1 2 3 0.65 BSC 1.10 0.80 0.10 MAX COPLANARITY 0.10 SEATING PLANE 0.30 0.15 0.40 0.10 0.46 0.36 0.26 0.22 0.08 072809-A 1.00 0.90 0.70 COMPLIANT TO JEDEC STANDARDS MO-203-AA Figure 50. 5-Lead Plastic Surface-Mount Package [SC70] (KS-5) Dimensions shown in millimeters 5.00 (0.1968) 4.80 (0.1890) 1 5 6.20 (0.2441) 5.80 (0.2284) 4 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.
PAGE 19
Data Sheet AD8625/AD8626/AD8627 3.20 3.00 2.80 5.15 4.90 4.65 5 8 3.20 3.00 2.80 1 4 PIN 1 IDENTIFIER 0.65 BSC 0.95 0.85 0.75 15° MAX 1.10 MAX 0.80 0.55 0.40 0.23 0.09 6° 0° 0.40 0.25 10-07-2009-B 0.15 0.05 COPLANARITY 0.10 COMPLIANT TO JEDEC STANDARDS MO-187-AA Figure 52. 8-Lead Mini Small Outline Package [MSOP] (RM-8) Dimensions shown in millimeters 8.75 (0.3445) 8.55 (0.3366) 4.00 (0.1575) 3.80 (0.1496) 8 14 1 7 6.20 (0.2441) 5.80 (0.2283) 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.
PAGE 20
AD8625/AD8626/AD8627 Data Sheet ORDERING GUIDE Model 1, 2 AD8625ARUZ AD8625ARUZ-REEL AD8625ARZ AD8625ARZ-REEL AD8625ARZ-REEL7 AD8626ARMZ-REEL AD8626ARMZ AD8626ARZ AD8626ARZ-REEL AD8626ARZ-REEL7 AD8627AKSZ-REEL AD8627AKSZ-REEL7 AD8627AKSZ-R2 AD8627ARZ AD8627ARZ-REEL AD8627ARZ-REEL7 1 2 Temperature Range –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +