AD AD8616ARMZ Precision, 20 mhz, cmos, rail-to-rail input/output operational amplifier Datasheet

Precision, 20 MHz, CMOS, Rail-to-Rail
Input/Output Operational Amplifiers
AD8615/AD8616/AD8618
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-torail, 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.
OUT 1
5
V+
4
–IN
AD8615
+IN 3
TOP VIEW
(Not to Scale)
04648-001
V– 2
OUT A
1
–IN A
2
+IN A
3
AD8616
TOP VIEW
V– 4 (Not to Scale)
8
V+
7
OUT B
6
–IN B
5
+IN B
04648-002
Figure 1. 5-Lead TSOT-23 (UJ-5)
Figure 2. 8-Lead MSOP (RM-8)
OUT A
1
–IN A
2
+IN A
3
AD8616
TOP VIEW
V– 4 (Not to Scale)
8
V+
7
OUT B
6
–IN B
5
+IN B
04648-003
APPLICATIONS
PIN CONFIGURATIONS
Figure 3. 8-Lead SOIC (R-8)
OUT A
–IN A
+IN A
V+
+IN B
–IN B
OUT B
1
OUT D
–IN D
+IN D
V–
+IN C
–IN C
OUT C
14
AD8618
TOP VIEW
(Not to Scale)
7
8
04648-004
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
Figure 4. 14-Lead TSSOP (RU-14)
OUT A 1
14
OUT D
–IN A 2
13
–IN D
12
+IN D
+IN A 3
AD8618
V+
4
11 V–
TOP VIEW
+IN B 5 (Not to Scale) 10 +IN C
–IN B
6
9
–IN C
OUT B 7
8
OUT C
04648-005
FEATURES
Figure 5. 14-Lead SOIC (R-14)
The AD8615/AD8616/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.
Rev. E
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113 ©2004–2008 Analog Devices, Inc. All rights reserved.
AD8615/AD8616/AD8618
TABLE OF CONTENTS
Features .............................................................................................. 1
Output Phase Reversal ............................................................... 11
Applications ....................................................................................... 1
Driving Capacitive Loads .......................................................... 11
General Description ......................................................................... 1
Overload Recovery Time .......................................................... 12
Pin Configurations ........................................................................... 1
D/A Conversion ......................................................................... 12
Revision History ............................................................................... 2
Low Noise Applications ............................................................. 12
Specifications..................................................................................... 3
High Speed Photodiode Preamplifier ...................................... 13
Absolute Maximum Ratings............................................................ 5
Active Filters ............................................................................... 13
Thermal Resistance ...................................................................... 5
Power Dissipation....................................................................... 13
ESD Caution .................................................................................. 5
Power Calculations for Varying or Unknown Loads............. 14
Typical Performance Characteristics ............................................. 6
Outline Dimensions ....................................................................... 15
Applications Information .............................................................. 11
Ordering Guide .......................................................................... 17
Input Overvoltage Protection ................................................... 11
REVISION HISTORY
9/08—Rev. D to Rev. E
Changes to General Description Section ...................................... 1
Updated Outline Dimensions ....................................................... 15
Changes to Ordering Guide .......................................................... 17
4/04—Rev. 0 to Rev. A
Added AD8618 ................................................................... Universal
Updated Outline Dimensions ....................................................... 16
1/04—Revision 0: Initial Version
5/08—Rev. C to Rev. D
Changes to Layout ............................................................................ 1
Changes to Figure 38 ...................................................................... 11
Changes to Figure 44 and Figure 45 ............................................. 13
Changes to Layout .......................................................................... 15
Changes to Layout .......................................................................... 16
6/05—Rev. B to Rev. C
Change to Table 1 ............................................................................. 3
Change to Table 2 ............................................................................. 4
Change to Figure 20 ......................................................................... 8
1/05—Rev. A to Rev. B
Added AD8615 ................................................................... Universal
Changes to Figure 12 ........................................................................ 8
Deleted Figure 19; Renumbered Subsequently ............................. 8
Changes to Figure 20 ........................................................................ 9
Changes to Figure 29 ...................................................................... 10
Changes to Figure 31 ...................................................................... 11
Deleted Figure 34; Renumbered Subsequently ........................... 11
Deleted Figure 35; Renumbered Subsequently ........................... 35
Rev. E | Page 2 of 20
AD8615/AD8616/AD8618
SPECIFICATIONS
VS =5 V, VCM = VS/2, TA = 25°C, unless otherwise noted.
Table 1.
Parameter
INPUT CHARACTERISTICS
Offset Voltage, AD8616/AD8618
Offset Voltage, AD8615
Offset Voltage Drift, AD8616/AD8618
Offset Voltage Drift, AD8615
Input Bias Current
Symbol
Conditions
VOS
VS = 3.5 V at VCM = 0.5 V and 3.0 V
∆VOS/∆T
VCM = 0 V to 5 V
−40°C < TA < +125°C
−40°C < TA < +125°C
Min
Typ
Max
Unit
23
23
80
60
100
500
800
7
10
1
50
550
0.5
50
250
5
μV
μV
μV
μV
μV/°C
μV/°C
pA
pA
pA
pA
pA
pA
V
dB
V/mV
pF
pF
1.5
3
0.2
IB
−40°C < TA < +85°C
−40°C < TA < +125°C
Input Offset Current
IOS
0.1
−40°C < TA < +85°C
−40°C < TA < +125°C
Input Voltage Range
Common-Mode Rejection Ratio
Large Signal Voltage Gain
Input Capacitance
OUTPUT CHARACTERISTICS
Output Voltage High
Output Voltage Low
Output Current
Closed-Loop Output Impedance
POWER SUPPLY
Power Supply Rejection Ratio
Supply Current per Amplifier
DYNAMIC PERFORMANCE
Slew Rate
Settling Time
Gain Bandwidth Product
Phase Margin
NOISE PERFORMANCE
Peak-to-Peak Noise
Voltage Noise Density
Current Noise Density
Channel Separation
CMRR
AVO
CDIFF
CCM
VCM = 0 V to 4.5 V
RL = 2 kΩ, VO = 0.5 V to 5 V
VOH
IL = 1 mA
IL = 10 mA
−40°C < TA < +125°C
IL = 1 mA
IL = 10 mA
−40°C < TA < +125°C
VOL
IOUT
ZOUT
0
80
105
4.98
4.88
4.7
100
1500
2.5
6.7
4.99
4.92
7.5
70
15
100
200
±150
3
f = 1 MHz, AV = 1
PSRR
ISY
VS = 2.7 V to 5.5 V
VO = 0 V
−40°C < TA < +125°C
SR
tS
GBP
Øm
RL = 2 kΩ
To 0.01%
12
<0.5
24
63
V/μs
μs
MHz
Degrees
en p-p
en
0.1 Hz to 10 Hz
f = 1 kHz
f = 10 kHz
f = 1 kHz
f = 10 kHz
f = 100 kHz
2.4
10
7
0.05
−115
−110
μV
nV/√Hz
nV/√Hz
pA/√Hz
dB
dB
in
CS
Rev. E | Page 3 of 20
70
90
1.7
V
V
V
mV
mV
mV
mA
Ω
2
2.5
dB
mA
mA
AD8615/AD8616/AD8618
VS = 2.7 V, VCM = VS/2, TA = 25°C, unless otherwise noted.
Table 2.
Parameter
INPUT CHARACTERISTICS
Offset Voltage, AD8616/AD8618
Offset Voltage, AD8615
Offset Voltage Drift, AD8616/AD8618
Offset Voltage Drift, AD8615
Input Bias Current
Symbol
Conditions
VOS
VS = 3.5 V at VCM = 0.5 V and 3.0 V
∆VOS/∆T
VCM = 0 V to 2.7 V
−40°C < TA < +125°C
−40°C < TA < +125°C
Min
Typ
Max
Unit
23
23
80
65
100
500
800
7
10
1
50
550
0.5
50
250
2.7
μV
μV
μV
μV
μV/°C
μV/°C
pA
pA
pA
pA
pA
pA
V
dB
V/mV
pF
pF
1.5
3
0.2
IB
−40°C < TA < +85°C
−40°C < TA < +125°C
Input Offset Current
IOS
0.1
−40°C < TA < +85°C
−40°C < TA < +125°C
Input Voltage Range
Common-Mode Rejection Ratio
Large Signal Voltage Gain
Input Capacitance
OUTPUT CHARACTERISTICS
Output Voltage High
Output Voltage Low
Output Current
Closed-Loop Output Impedance
POWER SUPPLY
Power Supply Rejection Ratio
Supply Current per Amplifier
DYNAMIC PERFORMANCE
Slew Rate
Settling Time
Gain Bandwidth Product
Phase Margin
NOISE PERFORMANCE
Peak-to-Peak Noise
Voltage Noise Density
Current Noise Density
Channel Separation
CMRR
AVO
CDIFF
CCM
VCM = 0 V to 2.7 V
RL = 2 kΩ, VO = 0.5 V to 2.2 V
VOH
IL = 1 mA
−40°C < TA < +125°C
IL = 1 mA
−40°C < TA < +125°C
VOL
IOUT
ZOUT
0
80
55
2.65
2.6
100
150
2.5
7.8
2.68
11
25
30
±50
3
f = 1 MHz, AV = 1
PSRR
ISY
VS = 2.7 V to 5.5 V
VO = 0 V
−40°C < TA < +125°C
SR
tS
GBP
Øm
RL = 2 kΩ
To 0.01%
12
<0.3
23
42
V/μs
μs
MHz
Degrees
en p-p
en
0.1 Hz to 10 Hz
f = 1 kHz
f = 10 kHz
f = 1 kHz
f = 10 kHz
f = 100 kHz
2.1
10
7
0.05
−115
−110
μV
nV/√Hz
nV/√Hz
pA/√Hz
dB
dB
in
CS
Rev. E | Page 4 of 20
70
90
1.7
V
V
mV
mV
mA
Ω
2
2.5
dB
mA
mA
AD8615/AD8616/AD8618
ABSOLUTE MAXIMUM RATINGS
THERMAL RESISTANCE
Table 3.
Parameter
Supply Voltage
Input Voltage
Differential Input Voltage
Output Short-Circuit Duration to GND
Storage Temperature Range
Operating Temperature Range
Lead Temperature (Soldering, 60 sec)
Junction Temperature
Rating
6V
GND to VS
±3 V
Indefinite
−65°C to +150°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. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
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
5-Lead TSOT-23 (UJ)
8-Lead MSOP (RM)
8-Lead SOIC (R)
14-Lead SOIC (R)
14-Lead TSSOP (RU)
ESD CAUTION
Rev. E | Page 5 of 20
θJA
207
210
158
120
180
θJC
61
45
43
36
35
Unit
°C/W
°C/W
°C/W
°C/W
°C/W
AD8615/AD8616/AD8618
TYPICAL PERFORMANCE CHARACTERISTICS
2200
350
VS = 5V
TA = 25°C
VCM = 0V TO 5V
2000
INPUT BIAS CURRENT (pA)
NUMBER OF AMPLIFIERS
1800
VS = ±2.5V
300
1600
1400
1200
1000
800
600
250
200
150
100
400
50
–700
–500
–300
–100
100
300
500
700
OFFSET VOLTAGE (µV)
0
04648-006
0
0
25
22
1000
125
100
16
14
VSY – VOUT (mV)
NUMBER OF AMPLIFIERS
100
VS = 5V
TA = 25°C
VS = ±2.5V
TA = –40°C TO +125°C
VCM = 0V
18
75
Figure 9. Input Bias Current vs. Temperature
Figure 6. Input Offset Voltage Distribution
20
50
TEMPERATURE (-°C)
04648-009
200
12
10
8
6
10
SOURCE
SINK
1
4
0
2
4
6
8
10
12
0.1
0.001
04648-007
0
TCVOS (µV/°C)
500
100
120
VS = 5V
TA = 25°C
VS = 5V
300
200
100
0
–100
–200
–300
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
COMMON-MODE VOLTAGE (V)
5.0
04648-008
–400
Figure 8. Input Offset Voltage vs. Common-Mode Voltage
(200 Units, Five Wafer Lots Including Process Skews)
100
10mA LOAD
80
60
40
20
1mA LOAD
0
–40
–25
–10
5
20
35
50
65
80
95
110
TEMPERATURE (°C)
Figure 11. Output Saturation Voltage vs. Temperature
Rev. E | Page 6 of 20
125
04648-011
OUTPUT SATURATION VOLTAGE (mV)
400
INPUT OFFSET VOLTAGE (µV)
10
Figure 10. Output Voltage to Supply Rail vs. Load Current
Figure 7. Offset Voltage Drift Distribution
–500
1
0.1
ILOAD (mA)
0.01
04648-010
2
AD8615/AD8616/AD8618
100
135
90
20
45
0
0
–20
–45
–40
–90
–60
–135
–80
–180
–100
1M
80
CMRR (dB)
40
PHASE (Degrees)
60
VS = ±2.5V
180
40
20
–225
60M
10M
FREQUENCY (Hz)
60
0
04648-012
80
1k
10k
1M
10M
Figure 15. CMRR vs. Frequency
Figure 12. Open-Loop Gain and Phase vs. Frequency
120
5.0
VS = ±2.5V
VS = 5.0V
VIN = 4.9V p-p
TA = 25°C
RL = 2kΩ
AV = 1
4.5
4.0
3.5
100
80
3.0
PSRR (dB)
OUTPUT SWING (V p-p)
100k
FREQUENCY (Hz)
2.5
2.0
60
40
1.5
1.0
20
10k
100k
1M
10M
FREQUENCY (Hz)
04648-013
1k
1k
10k
1000
50
VS = ±2.5V
SMALL-SIGNAL OVERSHOOT (%)
70
60
50
40
30
AV = 100
20
AV = 1
AV = 10
10
10k
VS = 5V
RL = ∞
TA = 25°C
AV = 1
45
80
OUTPUT IMPEDANCE (Ω)
10M
Figure 16. PSRR vs. Frequency
100
0
1k
1M
FREQUENCY (Hz)
Figure 13. Closed-Loop Output Voltage Swing vs. Frequency
90
100k
04648-016
0
0
04648-017
0.5
100k
40
35
30
25
20
15
–OS
10
+OS
5
1M
10M
FREQUENCY (Hz)
100M
04648-014
GAIN (dB)
120
225
VS = ±2.5V
TA = 25°C
Øm = 63°
04648-015
100
0
10
100
CAPACITANCE (pF)
Figure 17. Small-Signal Overshoot vs. Load Capacitance
Figure 14. Output Impedance vs. Frequency
Rev. E | Page 7 of 20
AD8615/AD8616/AD8618
VS = 5V
RL = 10kΩ
CL = 200pF
AV = 1
2.2
2.0
VS = 2.7V
1.8
VOLTAGE (50mV/DIV)
VS = 5V
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0
–40
–25
–10
5
20
35
50
65
80
95
110
125
TEMPERATURE (°C)
TIME (1µs/DIV)
Figure 21. Small Signal Transient Response
Figure 18. Supply Current vs. Temperature
VS = 5V
RL = 10kΩ
CL = 200pF
AV = 1
1800
VOLTAGE (500mV/DIV)
1600
1400
1200
1000
800
600
400
0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
SUPPLY VOLTAGE (V)
04648-022
200
04648-019
TIME (1s/DIV)
Figure 22. Large Signal Transient Response
Figure 19. Supply Current per Amplifier vs. Supply Voltage
0.1
1k
VS = ±2.5V
VS = ±1.35V
VS = ±2.5V
VIN = 0.5V rms
AV = 1
BW = 22kHz
RL = 100kΩ
0.01
THD+N (%)
100
0.001
1
10
100
1k
FREQUENCY (Hz)
10k
100k
04648-020
10
0.0001
20
100
1k
FREQUENCY (Hz)
Figure 23. THD + N vs. Frequency
Figure 20. Voltage Noise Density vs. Frequency
Rev. E | Page 8 of 20
20k
04648-023
SUPPLY CURRENT PER AMPLIFIER (µA)
2000
VOLTAGE NOISE DENSITY (nV/ Hz 0.5)
04648-021
0.2
04648-018
SUPPLY CURRENT PER AMPLIFIER (mA)
2.4
AD8615/AD8616/AD8618
500
VS = ±2.5V
VIN = 2V p-p
AV = 10
VS = 2.7V
TA = 25°C
VOLTAGE (2V/DIV)
INPUT OFFSET VOLTAGE (µV)
400
300
200
100
0
–100
–200
–300
–400
TIME (200ns/DIV)
0
0.3
0.6
0.9
1.2
1.5
1.8
2.1
2.4
2.7
COMMON-MODE VOLTAGE (V)
Figure 24. Settling Time
04648-027
04648-024
–500
Figure 27. Input Offset Voltage vs. Common-Mode Voltage
(200 Units, Five Wafer Lots Including Process Skews)
500
VS = 2.7V
VS = 3.5V
TA = 25°C
VOLTAGE (1µV/DIV)
INPUT OFFSET VOLTAGE (µV)
400
300
200
100
0
–100
–200
–300
04648-025
–500
TIME (1s/DIV)
1.0
1.5
2.0
2.5
3.0
3.5
COMMON-MODE VOLTAGE (V)
1000
1400
VS = 2.7V
TA = 25°C
VCM = 0V TO 2.7V
VS = ±1.35V
TA = 25°C
100
VSY – VOUT (mV)
1000
800
600
10
SOURCE
SINK
400
1
0
–700
–500
–300
–100
100
300
500
700
OFFSET VOLTAGE (µV)
0.1
0.001
0.01
0.1
ILOAD (mA)
1
Figure 29. Output Voltage to Supply Rail vs. Load Current
Figure 26. Input Offset Voltage Distribution
Rev. E | Page 9 of 20
10
04648-029
200
04648-026
NUMBER OF AMPLIFIERS
0.5
Figure 28. Input Offset Voltage vs. Common-Mode Voltage
(200 Units, Five Wafer Lots Including Process Skews)
Figure 25. 0.1 Hz to 10 Hz Input Voltage Noise
1200
0
04648-028
–400
AD8615/AD8616/AD8618
18
SMALL SIGNAL OVERSHOOT (%)
VOH @ 1mA LOAD
14
12
10
VOL @ 1mA LOAD
8
6
4
2
20
35
50
65
80
95
110
100
125
15
10
1000
VS = 2.7V
RL = 10kΩ
CL = 200pF
AV = 1
20
45
0
0
–20
–45
–40
–90
–60
–135
–80
–180
–225
60M
PHASE (Degrees)
90
VOLTAGE (50mV/DIV)
135
10M
FREQUENCY (Hz)
100
04648-031
TIME (1µs/DIV)
Figure 34. Small Signal Transient Response
Figure 31. Open-Loop Gain and Phase vs. Frequency
2.7
VS = 2.7V
RL = 10kΩ
CL = 200pF
AV = 1
VOLTAGE (500mV/DIV)
VS = 2.7V
VIN = 2.6V p-p
TA = 25°C
RL = 2kΩ
AV = 1
1.5
1.2
0.9
0.6
0
1k
10k
100k
1M
10M
FREQUENCY (Hz)
04648-032
0.3
Figure 32. Closed-Loop Output Voltage Swing vs. Frequency
TIME (1µs/DIV)
Figure 35. Large Signal Transient Response
Rev. E | Page 10 of 20
04648-035
GAIN (dB)
+OS
CAPACITANCE (pF)
180
–100
1M
OUTPUT SWING (V p-p)
–OS
20
Figure 33. Small Signal Overshoot vs. Load Capacitance
40
1.8
25
10
225
VS = ±1.35V
TA = 25°C
Øm = 42°
2.1
30
04648-033
5
04648-030
–10
Figure 30. Output Saturation Voltage vs. Temperature
2.4
35
0
–25
TEMPERATURE (°C)
60
40
5
0
–40
80
VS = ±1.35V
RL = ∞
TA = 25°C
AV = 1
45
04648-034
OUTPUT SATURATION VOLTAGE (mV)
16
50
VS = 2.7V
AD8615/AD8616/AD8618
APPLICATIONS INFORMATION
The AD8615/AD8616/AD8618 have internal protective circuitry
that allows voltages exceeding the supply to be applied at the input.
It is recommended, however, not to apply voltages that exceed
the supplies by more than 1.5 V at either input of the amplifier.
If a higher input voltage is applied, series resistors should be
used to limit the current flowing into the inputs.
The input current should be limited to <5 mA. 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.
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
AV = 1
CL = 500pF
VOLTAGE (100mV/DIV)
INPUT OVERVOLTAGE PROTECTION
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
Phase reversal can cause permanent damage to the amplifier
and can create lock ups in systems with feedback loops.
04648-037
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.
TIME (2µs/DIV)
Figure 37. Driving Heavy Capacitive Loads Without Compensation
VEE
+
–
VOUT
V–
V+
200Ω
VIN
–
200mV
VCC
500pF
500pF
04648-038
VOLTAGE (2V/DIV)
VS = ±2.5V
VIN = 6V p-p
AV = 1
RL = 10kΩ
VOLTAGE (100mV/DIV)
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.
VS = ±2.5V
AV = 1
RS = 200Ω
CS = 500pF
CL = 500pF
TIME (10µs/DIV)
04648-039
TIME (2ms/DIV)
04648-036
Figure 38. Snubber Network
Figure 39. Driving Heavy Capacitive Loads Using the Snubber Network
Rev. E | Page 11 of 20
AD8615/AD8616/AD8618
5V
OVERLOAD RECOVERY TIME
VDD
REFF
1/2
AD8616
DIN
SCLK
AD5542
VOUT
UNIPOLAR
OUTPUT
LDAC
DGND
AGND
Figure 42. Buffering DAC Output
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.
0V
0V
3
VIN
–50mV
V+
04648-040
R1
TIME (1µs/DIV)
REFS
CS
LOW NOISE APPLICATIONS
VS = ±2.5V
RL = 10kΩ
AV = 100
VIN = 50mV
+2.5V
0.1µF
0.1µF
SERIAL
INTERFACE
10µF
+
04648-042
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.
2.5V
2
1
V–
R3
100Ω
10Ω
R2
Figure 40. Positive Overload Recovery
1kΩ
3
V+
VS = ±2.5V
RL = 10kΩ
AV = 100
VIN = 50mV
R4
2
1
V–
R6
100Ω
10Ω
R5
–2.5V
0V
VOUT
1kΩ
3
0V
V+
R7
2
1
V–
R9
100Ω
10Ω
R8
1kΩ
+50mV
V+
R10
2
1
V–
R12
100Ω
10Ω
Figure 41. Negative Overload Recovery
R11
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.
Rev. E | Page 12 of 20
1kΩ
Figure 43. Noise Reduction
04648-043
TIME (1µs/DIV)
04648-041
3
AD8615/AD8616/AD8618
10
HIGH SPEED PHOTODIODE PREAMPLIFIER
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 get the maximum signal bandwidth, select
C2
–2.5V
CIN
+
V–
V+
+2.5V
–VBIAS
1
10
100
1k
10k
100k
1M
FREQUENCY (Hz)
Figure 46. Second-Order Butterworth, Low-Pass Filter Frequency Response
04648-044
–
CD
–40
0.1
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.
R2
RSH
–30
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.
where fU is the unity-gain bandwidth of the amplifier.
ID
–20
POWER DISSIPATION
C1
2πR 2 f U
C2 =
–10
04648-046
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.
0
GAIN (dB)
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.
1.5
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.
POWER DISSIPATION (W)
Figure 44. High Speed Photodiode Preamplifier
1.0
SOIC
MSOP
0.5
0
VEE
1nF
V+
VCC
04648-045
VIN
1.1kΩ
20
40
60
80
100
TEMPERATURE (°C)
120
140
Figure 47. Maximum Power Dissipation vs. Ambient Temperature
V–
1.1kΩ
0
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. E | Page 13 of 20
04648-047
2nF
AD8615/AD8616/AD8618
The following formula can be used to calculate the internal
junction temperature of the AD8615/AD8616/AD8618 for any
application:
Calculating Power by Measuring Ambient Temperature
and Case Temperature
The two equations for calculating the junction temperature are
TJ = PDISS × θJA + TA
TJ = TA + P θJA
where:
TJ = junction temperature
PDISS = power dissipation
θJA = package thermal resistance, junction-to-case
TA = ambient temperature of the circuit
where:
TJ = junction temperature
TA = ambient temperature
θJA = the junction-to-ambient thermal resistance
TJ = TC + P θJC
To calculate the power dissipated by the AD8615/AD8616/
AD8618, use the following:
where:
TC is case temperature.
θJA and θJC are given in the data sheet.
PDISS = ILOAD × (VS – VOUT)
where:
ILOAD = output load current
VS = supply voltage
VOUT = output voltage
The two equations for calculating P (power) are
The quantity within the parentheses is the maximum voltage
developed across either output transistor.
Once the power is determined, it is necessary to recalculate the
junction temperature to ensure that the temperature was not
exceeded.
TA + P θJA = TC + P θJC
P = (TA − TC)/(θJC − θJA)
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.
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. E | Page 14 of 20
AD8615/AD8616/AD8618
OUTLINE DIMENSIONS
2.90 BSC
5
4
2.80 BSC
1.60 BSC
1
2
3
0.95 BSC
1.90
BSC
*0.90 MAX
0.70 NOM
0.10 MAX
0.50
0.30
0.20
0.08
8°
4°
0°
SEATING
PLANE
0.60
0.45
0.30
091508-A
*1.00 MAX
*COMPLIANT TO JEDEC STANDARDS MO-193-AB WITH
THE EXCEPTION OF PACKAGE HEIGHT AND THICKNESS.
Figure 48. 5-Lead Thin Small Outline Transistor Package [TSOT]
(UJ-5)
Dimensions shown in millimeters
3.20
3.00
2.80
8
3.20
3.00
2.80
1
5
5.15
4.90
4.65
4
PIN 1
0.65 BSC
0.95
0.85
0.75
1.10 MAX
0.15
0.00
0.38
0.22
COPLANARITY
0.10
0.23
0.08
8°
0°
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MO-187-AA
Figure 49. 8-Lead Mini Small Outline Package [MSOP]
(RM-8)
Dimensions shown in millimeters
Rev. E | Page 15 of 20
0.80
0.60
0.40
AD8615/AD8616/AD8618
5.00 (0.1968)
4.80 (0.1890)
4.00 (0.1574)
3.80 (0.1497)
8
5
1
4
6.20 (0.2441)
5.80 (0.2284)
1.27 (0.0500)
BSC
1.75 (0.0688)
1.35 (0.0532)
0.25 (0.0098)
0.10 (0.0040)
0.51 (0.0201)
0.31 (0.0122)
COPLANARITY
0.10
SEATING
PLANE
0.50 (0.0196)
0.25 (0.0099)
45°
8°
0°
0.25 (0.0098)
0.17 (0.0067)
1.27 (0.0500)
0.40 (0.0157)
012407-A
COMPLIANT TO JEDEC STANDARDS MS-012-A A
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
Figure 50. 8-Lead Standard Small Outline Package [SOIC_N]
Narrow Body (R-8)
Dimensions shown in millimeters and (inches)
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 (0.0039)
COPLANARITY
0.10
0.50 (0.0197)
0.25 (0.0098)
1.75 (0.0689)
1.35 (0.0531)
SEATING
PLANE
0.51 (0.0201)
0.31 (0.0122)
45°
8°
0°
0.25 (0.0098)
0.17 (0.0067)
1.27 (0.0500)
0.40 (0.0157)
060606-A
COMPLIANT TO JEDEC STANDARDS MS-012-AB
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
Figure 51. 14-Lead Standard Small Outline Package [SOIC_N]
Narrow Body (R-14)
Dimensions shown in millimeters and (inches)
5.10
5.00
4.90
14
8
4.50
4.40
4.30
6.40
BSC
1
7
PIN 1
0.65 BSC
1.20
MAX
0.15
0.05
COPLANARITY
0.10
0.30
0.19
0.20
0.09
SEATING
PLANE
8°
0°
COMPLIANT TO JEDEC STANDARDS MO-153-AB-1
Figure 52. 14-Lead Thin Shrink Small Outline Package [TSSOP]
(RU-14)
Dimensions shown in millimeters
Rev. E | Page 16 of 20
0.75
0.60
0.45
061908-A
1.05
1.00
0.80
AD8615/AD8616/AD8618
ORDERING GUIDE
Model
AD8615AUJZ-R2 1
AD8615AUJZ-REEL1
AD8615AUJZ-REEL71
AD8616ARM-R2
AD8616ARM-REEL
AD8616ARMZ1
AD8616ARMZ-R21
AD8616ARMZ-REEL1
AD8616AR
AD8616AR-REEL
AD8616AR-REEL7
AD8616ARZ1
AD8616ARZ-REEL1
AD8616ARZ-REEL71
AD8618AR
AD8618AR-REEL
AD8618AR-REEL7
AD8618ARZ1
AD8618ARZ-REEL1
AD8618ARZ-REEL71
AD8618ARU
AD8618ARU-REEL
AD8618ARUZ1
AD8618ARUZ-REEL1
1
Temperature Range
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
Package Description
5-Lead TSOT-23
5-Lead TSOT-23
5-Lead TSOT-23
8-Lead MSOP
8-Lead MSOP
8-Lead MSOP
8-Lead MSOP
8-Lead MSOP
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
14-Lead SOIC_N
14-Lead SOIC_N
14-Lead SOIC_N
14-Lead SOIC_N
14-Lead SOIC_N
14-Lead SOIC_N
14-Lead TSSOP
14-Lead TSSOP
14-Lead TSSOP
14-Lead TSSOP
Z = RoHS Compliant Part.
Rev. E | Page 17 of 20
Package Option
UJ-5
UJ-5
UJ-5
RM-8
RM-8
RM-8
RM-8
RM-8
R-8
R-8
R-8
R-8
R-8
R-8
R-14
R-14
R-14
R-14
R-14
R-14
RU-14
RU-14
RU-14
RU-14
Branding
BKA
BKA
BKA
BLA
BLA
A0K
A0K
A0K
AD8615/AD8616/AD8618
NOTES
Rev. E | Page 18 of 20
AD8615/AD8616/AD8618
NOTES
Rev. E | Page 19 of 20
AD8615/AD8616/AD8618
NOTES
©2004–2008 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D04648-0-9/08(E)
Rev. E | Page 20 of 20
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