ANALOG DEVICES AD 8616 ARMZ Datasheet

Precision, 20 MHz, CMOS, Rail-to-Rail

Input/Output Operational Amplifiers

Data Sheet

FEATURES

Low offset voltage: 65 μV maximum Single-supply operation: 2.7 V to 5.0 V Low noise: 8 nV/√Hz Wide bandwidth: >20 MHz Slew rate: 12 V/μs High output current: 150 mA No phase reversal Low input bias current: 1 pA Low supply current: 2 mA Unity-gain stable

APPLICATIONS

Barcode scanners Battery-powered instrumentation Multipole filters Sensors ASIC input or output amplifiers Audio Photodiode amplification

GENERAL DESCRIPTION

The AD8615/AD8616/AD8618 are single/dual/quad, rail-to- rail, input and output, single-supply amplifiers featuring very low offset voltage, wide signal bandwidth, and low input voltage and current noise. The parts use a patented trimming technique that achieves superior precision without laser trimming. The

AD8615/AD8616/AD8618 are fully specified to operate from

2.7 V to 5 V single supplies. The combination of >20 MHz bandwidth, low offset, low noise,

and low input bias current makes these amplifiers useful in a wide variety of applications. Filters, integrators, photodiode amplifiers, and high impedance sensors all benefit from the combination of performance features. AC applications benefit from the wide bandwidth and low distortion. The AD8615/AD8616/

AD8618 offer the highest output drive capability of the DigiTrim®

family, which is excellent for audio line drivers and other low impedance applications.

Applications for the parts include portable and low powered instrumentation, audio amplification for portable devices, portable phone headsets, bar code scanners, and multipole filters. The ability to swing rail-to-rail at both the input and output enables designers to buffer CMOS ADCs, DACs, ASICs, and other wide output swing devices in single-supply systems.

AD8615/AD8616/AD8618

PIN CONFIGURATIONS

V+

1

OUT

AD8615

V–

2

TOP VIEW

(Not to S cale)

+IN

3

Fig

ure 1. 5-Lead TSOT-23 (UJ-5)

OUT A

1

AD8616

2

–IN A +IN A

3

TOP VIEW

(Not to Scale)

V–

4

Fig

ure 2. 8-Lead MSOP (RM-8)

OUT A

1

–IN A +IN A

OUT A

–IN A –IN D +IN A +IN D

+IN B +IN C –IN B –IN C

OUT B OUT C

Figure 4.

OUT A

–IN A +IN A

+IN B –IN B

OUT B

The AD8615/AD8616

AD8616

2 3

TOP VIEW

(Not to Scale)

4

V–

Fig

ure 3. 8-Lead SOIC (R-8)

1

AD8618

V+ V–

TOP VIEW

(Not to Scale)

7

14-Lead TSSOP (RU-14)

1 2 3

AD8618

V+

4

TOP VIEW

(Not to S cale)

5 6 7

Figure 5.

14-Lead SOIC (R-14)

/AD8618 are specified over the extended industrial temperature range (−40°C to +125°C). The AD8615 is available in 5-lead TSOT-23 package. The AD8616 is available in 8-lead MSOP and narrow SOIC surface-mount packages; the MSOP version is available in tape and reel only. The AD8618 is available in 14-lead SOIC and TSSOP packages.

5

4

–IN

04648-001

V+

8 7

OUT B –IN B

6

+IN B

5

8 7 6 5

14

8

14 13 12 11 10

9 8

V+ OUT B –IN B +IN B

OUT D

OUT D –IN D +IN D V– +IN C –IN C OUT C

04648-002

04648-003

4648-004

04648-005

Rev. G Document Feedback

Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners.

Technical Support www.analog.com

AD8615/AD8616/AD8618 Data Sheet

SPECIFICATIONS

VS = 5 V, VCM = VS/2, TA = 25°C, unless otherwise noted.

Table 1.

Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage, AD8615 23 100 µV VCM = 0 V to 5 V 80 500 µV

−40°C < TA < +125°C 800 µV Offset Voltage Drift, AD8616/AD8618 ∆VOS/∆T −40°C < TA < +125°C 1.5 7 µV/°C

Input Bias Current IB 0.2 1 pA

−40°C < TA < +85°C 50 pA

−40°C < TA < +125°C 550 pA Input Offset Current IOS 0.1 0.5 pA

−40°C < TA < +85°C 50 pA

Input Voltage Range 0 5 V Common-Mode Rejection Ratio CMRR VCM = 0 V to 4.5 V 80 100 dB Large Signal Voltage Gain AVO RL = 2 kΩ, VO = 0.5 V to 5 V 105 1500 V/mV Input Capacitance C

CCM 6.7 pF OUTPUT CHARACTERISTICS

Output Voltage High VOH IL = 1 mA 4.98 4.99 V

2.5 pF

DIFF

−40°C < TA < +125°C 4.7 V Output Voltage Low VOL IL = 1 mA 7.5 15 mV

IL = 10 mA 70 100 mV

−40°C < TA < +125°C 200 mV Output Current I

POWER SUPPLY

Power Supply Rejection Ratio PSRR VS = 2.7 V to 5.5 V 70 90 dB

−40°C < TA < +125°C 2.5 mA

Slew Rate SR RL = 2 kΩ 12 V/µs Settling Time tS To 0.01% <0.5 µs Gain Bandwidth Product GBP 24 MHz Phase Margin Øm 63 Degrees

NOISE PERFORMANCE

Peak-to-Peak Noise en p-p 0.1 Hz to 10 Hz 2.4 µV Voltage Noise Density en f = 1 kHz 10 nV/√Hz

f = 10 kHz 7 nV/√Hz

Channel Separation CS f = 10 kHz −115 dB

f = 100 kHz −110 dB

±150 mA

OUT

Rev. G | Page 3 of 20

AD8615/AD8616/AD8618 Data Sheet

VCM = 0 V to 2.7 V

80

500

µV

Large Signal Voltage Gain

AVO

RL = 2 kΩ, VO = 0.5 V to 2.2 V

55

150 V/mV

OUTPUT CHARACTERISTICS

DYNAMIC PERFORMANCE

VS = 2.7 V, VCM = VS/2, TA = 25°C, unless otherwise noted.

Table 2.

Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage, AD8616/AD8618 VOS VS = 3.5 V at VCM = 0.5 V and 3.0 V 23 65 µV Offset Voltage, AD8615 23 100 µV

−40°C < TA < +125°C 800 µV Offset Voltage Drift, AD8616/AD8618 ∆VOS/∆T −40°C < TA < +125°C 1.5 7 µV/°C Offset Voltage Drift, AD8615 3 10 µV/°C Input Bias Current IB 0.2 1 pA

−40°C < TA < +85°C 50 pA

−40°C < TA < +125°C 550 pA Input Offset Current IOS 0.1 0.5 pA

−40°C < TA < +85°C 50 pA

−40°C < TA < +125°C 250 pA Input Voltage Range 0 2.7 V Common-Mode Rejection Ratio CMRR VCM = 0 V to 2.7 V 80 100 dB

Input Capacitance C

2.5 pF

DIFF

CCM 7.8 pF

Output Voltage High VOH IL = 1 mA 2.65 2.68 V

−40°C < TA < +125°C 2.6 V Output Voltage Low VOL IL = 1 mA 11 25 mV

−40°C < TA < +125°C 30 mV Output Current I Closed-Loop Output Impedance Z

±50 mA

OUT

f = 1 MHz, AV = 1 3 Ω

OUT

POWER SUPPLY

Power Supply Rejection Ratio PSRR VS = 2.7 V to 5.5 V 70 90 dB Supply Current per Amplifier ISY VO = 0 V 1.7 2 mA

−40°C < TA < +125°C 2.5 mA

Slew Rate SR RL = 2 kΩ 12 V/µs Settling Time tS To 0.01% <0.3 µs Gain Bandwidth Product GBP 23 MHz Phase Margin Øm 42 Degrees

NOISE PERFORMANCE

Peak-to-Peak Noise en p-p 0.1 Hz to 10 Hz 2.1 µV Voltage Noise Density en f = 1 kHz 10 nV/√Hz f = 10 kHz 7 nV/√Hz Current Noise Density in f = 1 kHz 0.05 pA/√Hz Channel Separation CS f = 10 kHz −115 dB

f = 100 kHz −110 dB

Rev. G | Page 4 of 20

Data Sheet AD8615/AD8616/AD8618

Junction Temperature

150°C

8-Lead SOIC (R)

158

43

°C/W

ABSOLUTE MAXIMUM RATINGS

Table 3.

Parameter Rating

Supply Voltage 6 V Input Voltage GND to VS Differential Input Voltage ±6 V Output Short-Circuit Duration to GND Indefinite Storage Temperature Range −65°C to +150°C Operating Temperature Range −40°C to +125°C Lead Temperature (Soldering, 60 sec) 300°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. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

THERMAL RESISTANCE

θJA is specified for the worst-case conditions, that is, θJA is specified for a device soldered in a circuit board for surface-mount packages.

Table 4.

Package Type θJA θJC Unit

5-Lead TSOT-23 (UJ) 207 61 °C/W 8-Lead MSOP (RM) 210 45 °C/W

14-Lead SOIC (R) 120 36 °C/W 14-Lead TSSOP (RU) 180 35 °C/W

ESD CAUTION

Rev. G | Page 5 of 20

AD8615/AD8616/AD8618 Data Sheet

0

200

600

1400

1800

2200

1000

400

1200

1600

2000

800

NUMBER OF AMPLIFIERS

–700 –500 –300 –100 100 300 500

700

OFFSET VOLTAGE (µV)

VS = 5V T

A

= 25°C

V

CM

= 0V TO 5V

04648-006

0

2

6

14

18

22

10

4

12

16

20

8

NUMBER OF AMPLIFIERS

02

46810 12

TCV

OS

(µV/°C)

V

S

= ±2.5V

TA = –

40°C TO +125°C

VCM = 0V

04648-007

–400

–500

–300

–200

–100

0

100

200

300

400

500

INPUT OFFSET VOLTAGE (

µ

V)

0 0.5 1.0 1.5 2.0 2.5 3.0

3.5 4.0 4.5 5.0

COMMON-MODE VOLTAGE (V)

VS = 5V T

A

= 25°C

04648-008

0

50

100

150

200

250

300

350

INPUT BIAS CURRE NT (pA)

0 25 50 75 100 125

TEMPERATURE (-

°C)

V

S

=

±

2.5V

04648-009

SINK

SOURCE

1000

100

10

1

0.1

0.001 0.01 0.1

1 10

I

LOAD

(mA)

V

SY

– V

OUT

(mV)

100

V

S

= 5V

TA = 25°C

04648-010

0

20

40

60

80

100

120

OUTPUT SATURATIONVOLT

AGE (mV)

–40 –25 –10 5 20

35 50 65 80 95 110 125

TEMPERATURE (°C)

V

S

= 5V

1mA LOAD

10mA LOAD

04648-011

TYPICAL PERFORMANCE CHARACTERISTICS

Figure 6. Input Offset Voltage Distribution

Figure 7. Offset Voltage Drift Distribution

Figure 9. Input Bias Current vs. Temperature

Figure 10. Output Voltage to Supply Rail vs. Load Current

Figure 8. Input Offset Voltage vs. Common-Mode Voltage

(200 Units, Five Wafer Lots Including Process Skews)

Figure 11. Output Saturation Voltage vs. Temperature

Rev. G | Page 6 of 20

Data Sheet AD8615/AD8616/AD8618

1M 10M

100

80

60

40

20

0

–20

–40

–60

–80

–100

GAIN (dB)

225

180

135

90

45 0

–45

–90

–135

–180 –225

PHASE (Degrees)

VS = ±2.5V TA = 25°C Øm = 63°

60M

FREQUENCY (Hz)

04648-012

0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

OUTPUT SWING (V p-p)

FREQUENC

Y

(Hz)

10k

1k 100k

1M 10M

V

S

= 5.0V

V

IN

= 4.9V p-p

T

A

= 25

°

C

R

L

= 2kΩ

A

V

= 1

04648-013

0

10

20

30

40

50

60

70

80

90

100

OUTPUT IMPEDANCE (Ω)

1k 10k 100k 1M 10M 100M

FREQUENCY (Hz)

AV = 100 AV = 1

AV = 10

V

S

= ±2.5V

04648-014

0

20

40

60

80

100

120

CMRR (

dB)

FREQUENCY (Hz)

10k1k

100k

1M 10M

V

S

=

±

2.5V

04648-015

0

20

40

60

80

100

120

PSRR (

dB)

FREQUENCY (Hz)

10k1k 100k 1M 10M

V

S

= ±2.5V

04648-016

5

0

10

15

20

25

30

35

40

45

50

SMALL-SIGNAL OVERSHOOT (%)

CAPACITANCE (pF)

10 100 1000

VS = 5V RL =

∞

T

A

=

2

5°C

A

V

= 1

+OS

–OS

04648-017

Figure 12. Open-Loop Gain and Phase vs. Frequency

Figure 15. CMRR vs. Frequency

Figure 13. Closed-Loop Output Voltage Swing vs. Frequency

Figure 14. Output Impedance vs. Frequency

Figure 16. PSRR vs. Frequency

Figure 17. Small-Signal Overshoot vs. Load Capacitance

Rev. G | Page 7 of 20

AD8615/AD8616/AD8618 Data Sheet

0

0.4

0.8

0.6

0.2

1.2

1.0

SUPPLYCURRENT PER AMPLIFIER (mA)

1.6

1.4

2.0

1.8

2.4

2.2

–40 –25 –10 5 20 35 50

65 80

95

110

125

TEMPERA

TURE (

°

C)

VS = 2.7V

VS = 5V

04648-018

200

0

400

600

800

1000

1200

1400

1600

1800

2000

SUPPLY CURRENT PER AMPLIFIER (µA)

0 0.5

1.0

1.5 2.0 2.5 3.0 3.5 4.0 4.5

5.0

SUPP

LY VO

LTAGE (V)

04648-019

1k

100

10

1

10 100 1k 10k 100k

FREQUENCY (Hz)

VOLTAGE NOISE DENSITY (nV/ Hz

0.5

)

VS = ±2.5V V

S

= ±1.35V

04648-020

VOLT

AGE (50mV/DIV)

TIME (1

µ

s/DIV)

V

S

= 5V

R

L

= 10k

Ω

CL = 200pF A

V

= 1

04648-021

VOLT

AG

E (

500mV/DIV)

TIME (1s/DIV)

V

S

= 5V

R

L

= 10kΩ

C

L

= 200pF

AV = 1

04648-022

THD+N (%)

0.0001

0.01

0.001

0.1

FREQUENCY (Hz)

20 100 1k 20k

VS =

±2.5V

V

IN

= 0.5V rms AV = 1 BW = 22kHz RL = 100kΩ

04648-023

Figure 18. Supply Current vs. Temperature

Figure 19. Supply Current per Amplifier vs. Supply Voltage

Figure 21. Small Signal Transient Response

Figure 22. Large Signal Transient Response

Figure 20. Voltage Noise Density vs. Frequency

Figure 23. THD + N vs. Frequency

Rev. G | Page 8 of 20

Data Sheet AD8615/AD8616/AD8618

T

O

V

500

VS = 2.7V

400

T

= 25°C

A

300

200

100

0

–100

–200

INPUT OFFSET VOLTAGE (µV)

–300

–400

–500

0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7

COMMON-MO DE VO LTAGE (V)

Figure 27. Input Offset Voltage vs. Common-Mode Voltage

(200 Units, Five Wafer Lots Including Process Skews)

500

VS = 3.5V

400

T

= 25°C

A

300

200

100

0

–100

–200

INPUT OFFSET VOLTAGE (µV)

–300

–400

–500

0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

COMMON-MO DE VO LTAGE (V)

Figure 28. Input Offset Voltage vs. Common-Mode Voltage

(200 Units, Five Wafer Lots Including Process Skews)

1000

VS = ±1.35V

= 25°C

T

A

100

04648-027

04648-028

AGE (2V/DIV)

VOL

VOLTAGE (1µV/DIV)

1400

1200

1000

VS = ±2.5V V

= 2V p-p

IN

A

= 10

V

TIME (200n s/ DIV)

Figure 24. Settling Time

TIME (1s/DIV)

Figure 25. 0.1 Hz to 10 Hz Input Voltage Noise

VS = 2.7V

= 25°

C

T

A

VCM = 0V TO 2.7V

VS = 2.7V

04648-024

04648-025

800

F AMPLIFIERS

600

400

NUMBER

200

0

–700 –500 –300 –100 100 300 500 700

OFFSET VOLTAGE (µV)

Figure 26. Input Offset Voltage Distribution

4648-026

(mV)

OUT

10

–

SY

V

1

0.1

0.001 0.01 0.1 1 10

SOURCE

I

LOAD

SINK

(mA)

Figure 29. Output Voltage to Supply Rail vs. Load Current

04648-029

Rev. G | Page 9 of 20

AD8615/AD8616/AD8618 Data Sheet

A

G V

A

18

VS = 2.7V

16

14

12

10

TION VOLTAGE (mV)

8

TUR

6

4

OUTPUT S

2

0

VOL@ 1mA LOAD

–40 –25 –10 5 20 35 50 65 80 95 110 125

VOH@ 1mA LOAD

TEMPERATURE (°C)

Figure 30. Output Saturation Voltage vs. Temperature

100

VS = ±1.35V

80

T

= 25°C

A

Ø

= 42°

m

60

40

20

0

GAIN (dB)

–20

–40

–60

–80

–100

1M 10M

FREQUENCY ( Hz)

Figure 31. Open-Loop Gain and Phase vs. Frequency

2.7

VS = 2.7V

2.4

= 2.6V p-p

V

IN

= 25°C

T

A

2.1

= 2kΩ

R

L

= 1

A

1.8

1.5

1.2

0.9

0.6

0.3

V

0

10k1k 100k 1M 10M

FREQUENCY (Hz)

p-p)

(

OUTPUT SWIN

Figure 32. Closed-Loop Output Voltage Swing vs. Frequency

60M

225

180

135

90

45

0

–45

–90

–135

–180

–225

4648-030

PHASE (Degrees)

04648-031

04648-032

50

VS = ±1.35V

45

R

= ∞

L

T

= 25°C

A

40

A

= 1

V

35

30

25

L OVERSHOOT (%)

20

15

LL SIGN

10

SM

5

0

10 100 1000

CAPACITANCE (pF)

S

–O

Figure 33. Small Signal Overshoot vs. Load Capacitance

VS = 2.7V R

= 10kΩ

L

C

= 200pF

L

A

= 1

V

VOLTAGE (50mV/DIV)

TIME (1µs/DIV)

Figure 34. Small Signal Transient Response

VS = 2.7V R

= 10kΩ

L

C

= 200pF

L

A

= 1

V

VOLTAGE (500mV/ DIV)

TIME (1µs/DIV)

Figure 35. Large Signal Transient Response

+OS

04648-033

04648-035

4648-034

Rev. G | Page 10 of 20

Data Sheet AD8615/AD8616/AD8618

T

A

(

A

(

APPLICATIONS INFORMATION

INPUT OVERVOLTAGE PROTECTION

If the voltage applied at either input exceeds the supplies, place external resistors in series with the inputs. The resistor values can be determined by the equation

V



IN

SY

mA5



R

S

The extremely low input bias current allows the use of larger resistors, which allows the user to apply higher voltages at the inputs. The use of these resistors adds thermal noise, which contributes to the overall output voltage noise of the amplifier.

For example, a 10 kΩ resistor has less than 13 nV/√Hz of thermal noise and less than 10 nV of error voltage at room temperature.

OUTPUT PHASE REVERSAL

The AD8615/AD8616/AD8618 are immune to phase inversion, a phenomenon that occurs when the voltage applied at the input of the amplifier exceeds the maximum input common mode.

Phase reversal can cause permanent damage to the amplifier and can create lock ups in systems with feedback loops.

This reduces the overshoot and minimizes ringing, which in turn improves the frequency response of the AD8615/AD8616/

AD8618. One simple technique for compensation is the snubber,

which consists of a simple RC network. With this circuit in place, output swing is maintained and the amplifier is stable at all gains.

Figure 38 shows the implementation of the snubber, which reduces overshoot by more than 30% and eliminates ringing that can cause instability. Using the snubber does not recover the loss of bandwidth incurred from a heavy capacitive load.

VS = ±2.5V A

= 1

V

= 500pF

C

L

100mV/DIV)

GE

VOLT

VS= ±2.5V V

= 6V p-p

IN

A

= 1

V

R

= 10kΩ

L

V

AGE (2V/DIV)

VOL

OUT

TIME (2ms/DIV)

V

IN

04648-036

Figure 36. No Phase Reversal

DRIVING CAPACITIVE LOADS

Although the AD8615/AD8616/AD8618 are capable of driving capacitive loads of up to 500 pF without oscillating, a large amount of overshoot is present when operating at frequencies above 100 kHz. This is especially true when the amplifier is configured in positive unity gain (worst case). When such large capacitive loads are required, the use of external compensation is highly recommended.

TIME (2µs/DIV)

Figure 37. Driving Heavy Capacitive Loads Without Compensation

V

EE

+

V–

V+

–

200mV

200Ω

500pF

V

CC

500pF

Figure 38. Snubber Network

VS =±2.5V

= 1

A

V

= 200Ω

R

S

= 500pF

C

S

= 500pF

C

L

100mV/DIV)

GE

VOLT

4648-037

04648-038

TIME (10µs/DIV)

04648-039

Figure 39. Driving Heavy Capacitive Loads Using the Snubber Network

Rev. G | Page 11 of 20

AD8615/AD8616/AD8618 Data Sheet

V0V

0V

V

OVERLOAD RECOVERY TIME

Overload recovery time is the time it takes the output of the amplifier to come out of saturation and recover to its linear region. Overload recovery is particularly important in applications where small signals must be amplified in the presence of large transients. Figure 40 and Figure 41 show the positive and negative overload recovery times of the AD8616. In both cases, the time elapsed before the AD8616 comes out of saturation is less than 1 μs. In addition, the symmetry between the positive and negative recovery times allows excellent signal rectification without distortion to the output signal.

VS = ±2.5V R

= 10kΩ

L

A

= 100

+2.5V

0

–50mV

TIME (1µs/DIV)

V

IN

= 50mV

4648-040

Figure 40. Positive Overload Recovery

VS =±2.5V R

= 10kΩ

L

A

= 100

V

= 50mV

IN

–

2.5V

+50mV

TIME (1µs/DIV)

Figure 41. Negative Overload Recovery

04648-041

D/A CONVERSION

The AD8616 can be used at the output of high resolution DACs. The low offset voltage, fast slew rate, and fast settling time make the part suitable to buffer voltage output or current output DACs.

Figure 42 shows an example of the AD8616 at the output of the

AD5542. The AD8616’s rail-to-rail output and low distortion

help maintain the accuracy needed in data acquisition systems and automated test equipment.

5

2.5 10µF

+

SERIAL

INTERFACE

0.1

µF

DD

CS

DIN SCLK

LDAC

REFFV

AD5542

0.1µF

AGNDDGND

REFS

1/2 AD8616

V

OUT

UNIPOL AR

OUTPUT

Figure 42. Buffering DAC Output

LOW NOISE APPLICATIONS

Although the AD8618 typically has less than 8 nV/√Hz of voltage noise density at 1 kHz, it is possible to reduce it further. A simple method is to connect the amplifiers in parallel, as shown in Figure 43. The total noise at the output is divided by the square root of the number of amplifiers. In this case, the total noise is approximately 4 nV/√Hz at room temperature. The 100 Ω resistor limits the current and provides an effective output resistance of 50 Ω.

V

IN

3

V+

R1

10Ω

R4

10Ω

R7

10Ω

R10

10Ω

2

3

2

3

2

3

2

V–

R2

1kΩ

V+

V–

R5

1kΩ

V+

V–

R8

1kΩ

V+

V–

R11

1kΩ

1

Figure 43. Noise Reduction

R3

100Ω

R6

100Ω

R9

100Ω

R12

100Ω

V

OUT

04648-043

4648-042

Rev. G | Page 12 of 20

Data Sheet AD8615/AD8616/AD8618

U

f2R

1C

2Cπ=

2

V–

+2.5V

V+

–2.5V

R2

C2

C

IN

C

D

R

SH

I

D

–V

BIAS

–

+

04648-044

V–

V

CC

V+

V

EE

2nF

1nF

1.1k

Ω

1.1k

Ω

V

IN

04648-045

–40

–30

–20

–10

0

10

GAIN (dB)

10.1 10 100 1k 10k 100k 1M FREQUENCY (Hz)

04648-046

POWER DISSIPATION (W)

TEMPERATURE (°C)

0

0.5

1.0

1.5

20

40 60 80

120100 140

SOIC

MSOP

04648-047

HIGH SPEED PHOTODIODE PREAMPLIFIER

The AD8615/AD8616/AD8618 are excellent choices for I-to-V conversions. The very low input bias, low current noise, and high unity-gain bandwidth of the parts make them suitable, especially for high speed photodiode preamplifiers.

In high speed photodiode applications, the diode is operated in a photoconductive mode (reverse biased). This lowers the junction capacitance at the expense of an increase in the amount of dark current that flows out of the diode.

The total input capacitance, C1, is the sum of the diode and op amp input capacitances. This creates a feedback pole that causes degradation of the phase margin, making the op amp unstable. Therefore, it is necessary to use a capacitor in the feedback to compensate for this pole.

To ge t the maximum signal bandwidth, select

where f

is the unity-gain bandwidth of the amplifier.

U

Figure 46. Second-Order Butterworth, Low-Pass Filter Frequency Response

POWER DISSIPATION

Although the AD8615/AD8616/AD8618 are capable of providing load currents up to 150 mA, the usable output, load current, and drive capability are limited to the maximum power dissipation allowed by the device package.

In any application, the absolute maximum junction temperature for the AD8615/AD8616/AD8618 is 150°C. This should never be exceeded because the device could suffer premature failure. Accurately measuring power dissipation of an integrated circuit is not always a straightforward exercise; Figure 47 is a design aid for setting a safe output current drive level or selecting a heat sink for the package options available on the AD8616.

Figure 44. High Speed Photodiode Preamplifier

ACTIVE FILTERS

The low input bias current and high unity-gain bandwidth of the AD8616 make it an excellent choice for precision filter design.

Figure 45 shows the implementation of a second-order, low-pass filter. The Butterworth response has a corner frequency of 100 kHz and a phase shift of 90°. The frequency response is shown in Figure 46.

Figure 47. Maximum Power Dissipation vs. Ambient Temperature

These thermal resistance curves were determined using the

AD8616 thermal resistance data for each package and a

maximum junction temperature of 150°C.

Figure 45. Second-Order, Low-Pass Filter

Rev. G | Page 13 of 20

AD8615/AD8616/AD8618 Data Sheet

The following formula can be used to calculate the internal junction temperature of the AD8615/AD8616/AD8618 for any application:

T

= P

× θJA + TA

J

DISS

where:

T

= junction temperature

J

= power dissipation

P

DISS

θ

= package thermal resistance, junction-to-case

JA

= ambient temperature of the circuit

T

A

To calculate the power dissipated by the AD8615/AD8616/

AD8618, use the following:

= I

P

DISS

× (VS – V

LOAD

OUT

)

where:

I

= output load current

LOAD

= supply voltage

V

S

= output voltage

V

OUT

The quantity within the parentheses is the maximum voltage developed across either output transistor.

POWER CALCULATIONS FOR VARYING OR UNKNOWN LOADS

Often, calculating power dissipated by an integrated circuit to determine if the device is being operated in a safe range is not as simple as it may seem. In many cases, power cannot be directly measured. This may be the result of irregular output waveforms or varying loads. Indirect methods of measuring power are required.

There are two methods to calculate power dissipated by an integrated circuit. The first is to measure the package temperature and the board temperature. The second is to directly measure the circuit’s supply current.

Calculating Power by Measuring Ambient Temperature and Case Temperature

The two equations for calculating the junction temperature are

= TA + P θJA

T

J

where:

T

= junction temperature

J

= ambient temperature

T

A

θ

= the junction-to-ambient thermal resistance

JA

= TC + P θJC

T

J

where:

T

is case temperature.

C

θ

and θJC are given in the data sheet.

JA

The two equations for calculating P (power) are

+ P θJA = TC + P θJC

T

A

− TC)/(θJC − θJA)

P = (T

A

Once the power is determined, it is necessary to recalculate the junction temperature to ensure that the temperature was not exceeded.

The temperature should be measured directly on and near the package but not touching it. Measuring the package can be difficult. A very small bimetallic junction glued to the package can be used, or an infrared sensing device can be used, if the spot size is small enough.

Calculating Power by Measuring Supply Current

If the supply voltage and current are known, power can be calculated directly. However, the supply current can have a dc component with a pulse directed into a capacitive load, which can make the rms current very difficult to calculate. This difficulty can be overcome by lifting the supply pin and inserting an rms current meter into the circuit. For this method to work, make sure the current is delivered by the supply pin being measured. This is usually a good method in a single-supply system; however, if the system uses dual supplies, both supplies may need to be monitored.

Rev. G | Page 14 of 20

Data Sheet AD8615/AD8616/AD8618

091508-A

*

COMPLIANT TO JEDEC S TANDARDS MO-193-AB WITH

THE EXCEPT ION OF P ACKAGE HEIGHT AND THICKNESS.

1.60 BSC

2.80 BSC

1.90

BSC

0.95 BSC

0.20

0.08

0.60

0.45

0.30

8° 4° 0°

0.50

0.30

0.10 MAX

*

1.00 MAX

0.90 MAX

0.70 NOM

2.90 BSC

5 4

1 2 3

SEATING PLANE

COMPLI ANT TO JEDEC STANDARDS MO-187-AA

6° 0°

0.80

0.55

0.40

4

8

1

5

0.65 BSC

0.40

0.25

1.10 MAX

3.20

3.00

2.80

COPLANARITY

0.10

0.23

0.09

3.20

3.00

2.80

5.15

4.90

4.65

PIN 1

IDENTIFIER

15° MAX

0.95

0.85

0.75

0.15

0.05

10-07-2009-B

OUTLINE DIMENSIONS

Figure 48. 5-Lead Thin Small Outline Transistor Package [TSOT]

(UJ-5)

Dimensions shown in millimeters

Figure 49. 8-Lead Mini Small Outline Package [MSOP]

(RM-8)

Dimensions shown in millimeters

Rev. G | Page 15 of 20

AD8615/AD8616/AD8618 Data Sheet

CONTROLLING DIMENSIONSARE IN M ILLIME TERS; INCH DI M E NS IONS (IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR REFERENCE ONLYAND ARE NO T APPROPRI

A

TE FOR USE IN DESIGN.

COMPLIANT TO JEDEC STANDARDS MS-012-A A

012407-A

0.25 (0.0098)

0.17 (0.0067)

1.27 (0.0500)

0.40 (0.0157)

0.50 (0.0196)

0.25 (0.0099)

45°

8° 0°

1.75 (0.0688)

1.35 (0.0532)

SEA

TING

PLANE

0.25 (0.0098)

0.10 (0.0040)

4

1

8 5

5.00 (0.1968)

4.80

(0.1890)

4.00 (0.1574)

3.80 (0.1497)

1.27 (0.0500) BSC

6.20 (0.2441)

5.80 (0.2284)

0.51 (0.0201)

0.31 (0.0122)

COPLANARITY

0.10

CONTROLLING DIMENSIONSARE IN M ILLIME TERS; INCH DI M E NS IONS (IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR REFERENCE ONLYAND ARE NO T APPROPRIATE FOR USE IN DESIGN.

COMPLIANT TO JEDEC STANDARDS MS-012-AB

060606-A

14

8

7

1

6.20 (0.2441)

5.80 (0.2283)

4.00 (0.1575)

3.80 (0.1496)

8.75 (0.3445)

8.55 (0.3366)

1.27 (0.0500) BSC

SEATING PLANE

0.25 (0.0098)

0.10 (0.0039)

0.51 (0.0201)

0.31 (0.0122)

1.75 (0.0689)

1.35 (0.0531)

0.50 (0.0197)

0.25 (0.0098)

1.27 (0.0500)

0.40 (0.0157)

0.25 (0.0098)

0.17 (0.0067)

COPLANARITY

0.10

8° 0°

45°

COMPLIANT TO JEDEC S TANDARDS MO-153-AB- 1

061908-A

8° 0°

4.50

4.40

4.30

14

8

7

1

6.40

BSC

PIN 1

5.10

5.00

4.90

0.65 BSC

0.15

0.05

0.30

0.19

1.20 MAX

1.05

1.00

0.80

0.20

0.09

0.75

0.60

0.45

COPLANARITY

0.10

SEATING PLANE

Figure 50. 8-Lead Standard Small Outline Package [SOIC_N]

Narrow Body (R-8)

Dimensions shown in millimeters and (inches)

Figure 51. 14-Lead Standard Small Outline Package [SOIC_N]

Narrow Body (R-14)

Dimensions shown in millimeters and (inches)

Figure 52. 14-Lead Thin Shrink Small Outline Package [TSSOP]

Dimensions shown in millimeters

(RU-14)

Rev. G | Page 16 of 20

Data Sheet AD8615/AD8616/AD8618

Model1

Temperature Range

Package Description

Package Option

Branding

AD8615AUJZ-REEL

–40°C to +125°C

5-Lead TSOT-23

UJ-5

BKA

AD8616ARMZ-REEL

–40°C to +125°C

8-Lead MSOP

RM-8

A0K

AD8618ARUZ

–40°C to +125°C

14-Lead TSSOP

RU-14

ORDERING GUIDE

AD8615AUJZ-R2 –40°C to +125°C 5-Lead TSOT-23 UJ-5 BKA

AD8615AUJZ-REEL7 –40°C to +125°C 5-Lead TSOT-23 UJ-5 BKA AD8616ARMZ –40°C to +125°C 8-Lead MSOP RM-8 A0K

AD8616AR –40°C to +125°C 8-Lead SOIC_N R-8 AD8616ARZ –40°C to +125°C 8-Lead SOIC_N R-8 AD8616ARZ-REEL –40°C to +125°C 8-Lead SOIC_N R-8 AD8616ARZ-REEL7 –40°C to +125°C 8-Lead SOIC_N R-8 AD8618ARZ –40°C to +125°C 14-Lead SOIC_N R-14 AD8618ARZ-REEL –40°C to +125°C 14-Lead SOIC_N R-14 AD8618ARZ-REEL7 –40°C to +125°C 14-Lead SOIC_N R-14

AD8618ARUZ-REEL –40°C to +125°C 14-Lead TSSOP RU-14

1

Z = RoHS Compliant Part.

Rev. G | Page 17 of 20

AD8615/AD8616/AD8618 Data Sheet

NOTES

Rev. G | Page 18 of 20

Data Sheet AD8615/AD8616/AD8618

NOTES

Rev. G | Page 19 of 20

AD8615/AD8616/AD8618 Data Sheet

NOTES

registered trademarks are the property of their respective owners. D04648-0-6/14(G)

Rev. G | Page 20 of 20

ANALOG DEVICES AD 8616 ARMZ Datasheet

Specifications and Main Features

Frequently Asked Questions

User Manual

FEATURES

APPLICATIONS

GENERAL DESCRIPTION

TABLE OF CONTENTS

REVISION HISTORY

SPECIFICATIONS

ABSOLUTE MAXIMUM RATINGS

THERMAL RESISTANCE

ESD CAUTION

TYPICAL PERFORMANCE CHARACTERISTICS

APPLICATIONS INFORMATION

INPUT OVERVOLTAGE PROTECTION

OUTPUT PHASE REVERSAL

DRIVING CAPACITIVE LOADS

OVERLOAD RECOVERY TIME

D/A CONVERSION

LOW NOISE APPLICATIONS

HIGH SPEED PHOTODIODE PREAMPLIFIER

POWER DISSIPATION

ACTIVE FILTERS

POWER CALCULATIONS FOR VARYING OR UNKNOWN LOADS

Calculating Power by Measuring Ambient Temperature and Case Temperature

Calculating Power by Measuring Supply Current

OUTLINE DIMENSIONS

ORDERING GUIDE