Analog Devices AD829 g Datasheet

High Speed, Low Noise

Video Op Amp

AD829

FEATURES
High Speed

120 MHz Bandwidth, Gain = –1
230 V/␮s Slew Rate
90 ns Settling Time to 0.1%

Ideal for Video Applications

0.02% Differential Gain

0.04ⴗ Differential Phase

Low Noise

1.7 nV/√Hz Input Voltage Noise

1.5 pA/√Hz Input Current Noise

Excellent DC Precision

1 mV Max Input Offset Voltage (Over Temp)

0.3 mV/ⴗC Input Offset Drift

Flexible Operation

Specified for ⴞ5 V to ⴞ15 V Operation
ⴞ3 V Output Swing into a 150 ⍀ Load
External Compensation for Gains 1 to 20
5 mA Supply Current

Available in Tape and Reel in Accordance with

EIA-481A Standard

GENERAL DESCRIPTION

The AD829 is a low noise (1.7 nV/√Hz), high speed op amp
with custom compensation that provides the user with gains of
±1 to ±20 while maintaining a bandwidth greater than 50 MHz.
The AD829’s 0.04° differential phase and 0.02% differential
gain performance at 3.58 MHz and 4.43 MHz, driving reverse­terminated 50 Ω or 75 Ω cables, makes it ideally suited for
professional video applications. The AD829 achieves its 230 V/µs
uncompensated slew rate and 750 MHz gain bandwidth while
requiring only 5 mA of current from power supplies.

The AD829’s external compensation pin gives it exceptional
versatility. For example, compensation can be selected to
optimize the bandwidth for a given load and power supply voltage.
As a gain-of-two line driver, the –3 dB bandwidth can be increased
to 95 MHz at the expense of 1 dB of peaking. The AD829’s
output can also be clamped at its external compensation pin.

The AD829 exhibits excellent dc performance. It offers a mini­mum open-loop gain of 30 V/mV into loads as low as 500 Ω,
low input voltage noise of 1.7 nV/√Hz, and a low input offset
voltage of 1 mV maximum. Common-mode rejection and power
supply rejection ratios are both 120 dB.

This op amp is also useful in multichannel, high speed data
conversion where its fast (90 ns to 0.1%) settling time is impor­tant. In such applications, the AD829 serves as an input buffer
for 8-bit to 10-bit A/D converters and as an output I/V con­verter for high speed DACs.

REV. G

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. 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.

CONNECTION DIAGRAMS

8-Lead

PDIP(N), Cerdip (Q), and SOIC (R) Packages

OFFSET NULL

–IN

+IN

–V

1

2

3

4

S

AD829

TOP VIEW

(Not to Scale)

8

OFFSET NULL

+V

7

S

6

OUTPUT

C

5

COMP

20-Lead LCC Pinout

NC

NC

OFFSET

NULL

OFFSET

NULL

NC

20 19123

NC

COMP

C

NC

18

+V

17

NC

16

OUTPUT

15

14

NC

4

NC

5

–IN

6

NC

+IN

NC

NC = NO CONNECT

7

8

910111213

TOP VIEW

(Not to Scale)

NC

AD829

NC

–V

Operating as a traditional voltage feedback amplifier, the AD829
provides many of the advantages a transimpedance amplifier
offers. A bandwidth greater than 50 MHz can be maintained for
a range of gains through the replacement of the external com­pensation capacitor. The AD829 and the transimpedance
amplifier are both unity gain stable and provide similar voltage
noise performance (1.7 nV/√Hz); however, the current noise of
the AD829 (1.5 pA/√Hz) is less than 10% of the noise of
transimpedance amps. The inputs of the AD829 are symmetrical.

PRODUCT HIGHLIGHTS

1. Input voltage noise of 2 nV/√Hz, current noise of 1.5 pA/√Hz,

and 50 MHz bandwidth, for gains of 1 to 20, make the AD829
an ideal preamp.

2. Differential phase error of 0.04° and a 0.02% differential

gain error, at the 3.58 MHz NTSC and 4.43 MHz PAL and
SECAM color subcarrier frequencies, make the op amp an
outstanding video performer for driving reverse-terminated
50 Ω and 75 Ω cables to ± 1 V (at their terminated end).

3. The AD829 can drive heavy capacitive loads.

4. Performance is fully specified for operation from ±5 V to
±15 V supplies.

5. The AD829 is available in plastic, CERDIP, and small outline
packages. Chips and MIL-STD-883B parts are also available.
The SOIC-8 package is available for the extended tempera­ture range of –40°C to +125°C.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] © 2004 Analog Devices, Inc. All rights reserved.

AD829–SPECIFICATIONS

(@ TA = 25ⴗC and VS = ⴞ15 V dc, unless otherwise noted.)

Model Conditions V

S

Min Typ Max Min Typ Max Min Typ Max Unit

INPUT OFFSET VOLTAGE ±5 V, ±15 V 0.2 1 0.2 1 0.1 0.5 mV

AD829JR AD829AR AD829AQ/S

T

MIN

to T

MAX

110.5 mV

Offset Voltage Drift ±5 V, ±15 V 0.3 0.3 0.3 µV/°C

INPUT BIAS CURRENT ±5 V, ±15 V 3.3 7 3.3 7 3.3 7 µA

T

MIN

to T

MAX

8.2 9.5 9.5 µA

INPUT OFFSET CURRENT ±5 V, ±15 V 50 500 50 500 50 500 nA

T

MIN

to T

MAX

500 500 500 nA

Offset Current Drift ±5 V, ±15 V 0.5 0.5 0.5 nA/°C

OPEN-LOOP GAIN V

= ±2.5 V ± 5 V

O

R

= 500 Ω 30 65 30 65 30 65 V/mV

LOAD

to T

T

MIN

R
V
R
T

R

MAX

= 150 Ω 40 40 40 V/mV

LOAD

= ± 10 V ± 15 V

OUT

= 1 kΩ 50 100 50 100 50 100 V/mV

LOAD

to T

MIN

MAX

= 500 Ω 85 85 85 V/mV

LOAD

20 20 20 V/mV

20 20 20 V/mV

DYNAMIC PERFORMANCE

Gain Bandwidth Product ±5 V 600 600 600 MHz

Full Power Bandwidth

1, 2

VO = 2 V p-p
R

= 500 Ω±5 V 25 25 25 MHz

LOAD

±15 V 750 750 750 MHz

VO = 20 V p-p
R

= 1 kΩ±15 V 3.6 3.6 3.6 MHz

Slew Rate

2

LOAD

R

= 500 Ω±5 V 150 150 150 V/µs

LOAD

R

= 1 kΩ±15 V 230 230 230 V/µs

LOAD

Settling Time to 0.1% AV = –19

–2.5 V to +2.5 V ±5 V 65 65 65 ns

Phase Margin

DIFFERENTIAL GAIN ERROR

2

3

DIFFERENTIAL PHASE ERROR3R

10 V Step ±15 V 90 90 90 ns
C

= 10 pF ±15 V

LOAD

R

= 1 kΩ 60 60 60 Degrees

LOAD

R

= 100 Ω±15 V

LOAD

C

= 30 pF 0.02 0.02 0.02

COMP

= 100 Ω±15 V

LOAD

C

= 30 pF 0.04 0.04 0.04 Degrees

COMP

%

COMMON-MODE REJECTION VCM = ± 2.5 V ±5 V 100 120 100 120 100 120 dB

VCM = ± 12 V ±15 V 100 120 100 120 100 120 dB
T

MIN

to T

MAX

96 96 96 dB

POWER SUPPLY REJECTION VS = ± 4.5 V to ±18 V 98 120 98 120 98 120 dB

T

MIN

to T

MAX

94 94 94 dB

INPUT VOLTAGE NOISE f = 1 kHz ±15 V 1.7 2 1.7 2 1.7 2 nV/√Hz

INPUT CURRENT NOISE f = 1 kHz ± 15 V 1.5 1.5 1.5 pA/√Hz

INPUT COMMON-MODE

VOLTAGE RANGE ±5 V +4.3 +4.3 +4.3 V

–3.8 –3.8 –3.8 V

±15 V +14.3 +14.3 +14.3 V

–13.8 –13.8 –13.8 V

OUTPUT VOLTAGE SWING R

= 500 Ω±5 V ±3.0 ± 3.6 ±3.0 ±3.6 ±3.0 ± 3.6 V

LOAD

R

= 150 Ω±5 V ±2.5 ± 3.0 ±2.5 ±3.0 ±2.5 ± 3.0 V

LOAD

R

50 Ω±5 V ± 1.4 ±1.4 ±1.4 V

LOAD =

R

= 1 kΩ±15 V ± 12 ± 13.3 ±12 ±13.3 ± 12 ±13.3 V

LOAD

R

= 500 Ω±15 V ± 10 ± 12.2 ±10 ±12.2 ± 10 ±12.2 V

LOAD

Short Circuit Current ±5 V, ±15 V 32 32 32 mA

INPUT CHARACTERISTICS

Input Resistance (Differential) 13 13 13 kΩ
Input Capacitance (Differential)

4

55 5pF

Input Capacitance (Common Mode) 1.5 1.5 1.5 pF

CLOSED-LOOP OUTPUT

RESISTANCE AV = +1, f = 1 kHz 2 2 2 mΩ

–2–

REV. G

AD829

Model Conditions V

S

Min Typ Max Min Typ Max Min Typ Max Unit

POWER SUPPLY

Operating Range ±4.5 ±18 ±4.5 ±18 ± 4.5 ± 18 V
Quiescent Current ±15 V 5 6.5 5 6.5 5 6.5 mA

AD829JR AD829AR AD829AQ/S

T

MIN

to T

MAX

8.0 8.0 8.2/8.7 mA

±15 V 5.3 6.8 5.3 6.8 5.3 6.8 mA

T

MIN

to T

MAX

8.3 9.0 8.5/9.0 mA

TRANSISTOR COUNT Number of Transistors 46 46 46

NOTES

1

Full Power Bandwidth = Slew Rate/2 π V

2

Tested at Gain = +20, C

3

3.58 MHz (NTSC) and 4.43 MHz (PAL and SECAM).

4

Differential input capacitance consists of 1.5 pF package capacitance plus 3.5 pF from the input differential pair.

COMP

= 0 pF.

PEAK

.

Specifications subject to change without notice.

REV. G

–3–

AD829

ABSOLUTE MAXIMUM RATINGS

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±18 V

Internal Power Dissipation

2

1

PDIP (N) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 W

SOIC (R) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.9 W

CERDIP (Q) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 W

LCC (E) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.8 W

Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±V

Differential Input Voltage

3

. . . . . . . . . . . . . . . . . . . . . . . ± 6 V

Output Short Circuit Duration . . . . . . . . . . . . . . . . . Indefinite

Storage Temperature Range (Q, E) . . . . . . . . –65°C to +150°C

Storage Temperature Range (N, R) . . . . . . . . –65°C to +125°C

Operating Temperature Range

AD829J . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C

AD829A . . . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to +125°C

AD829S . . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to +125°C

Lead Temperature Range (Soldering 60 sec) . . . . . . . . . 300°C

NOTES

1

Stresses above those listed under Absolute Maximum Ratings may cause perma­nent damage to the device. This is a stress rating only; the 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.

2

Maximum internal power dissipation is specified so that TJ does not exceed
150°C at an ambient temperature of 25°C.
Thermal characteristics:

8-lead PDIP package: θJA = 100°C/W (derate at 8.7 mW/°C)
8-lead CERDIP package: θJA = 110°C/W (derate at 8.7 mW/°C)
20-lead LCC package: θJA = 77°C/W
8-lead SOIC package: θJA = 125°C/W (derate at 6 mW/°C).

3

If the differential voltage exceeds 6 V, external series protection resistors should
be added to limit the input current.

METALLIZATION PHOTO

Contact factory for latest dimensions.

Dimensions shown in inches and (mm).

SUBSTRATE CONNECTED TO +V

2.5

2.0

1.5

1.0

PDIP

CERDIP

S

LCC

0.5

MAXIMUM POWER DISSIPATION (W)

0

–55 –45–35 –25–15 –5 5 15 25 35 45 55 65 75 85 95 105 115 125

SOIC

AMBIENT TEMPERATURE (ⴗC)

Figure 1. Maximum Power Dissipation vs. Temperature

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although the
AD829 features proprietary ESD protection circuitry, permanent damage may occur on devices
subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended
to avoid performance degradation or loss of functionality.

REV. G–4–

ORDERING GUIDE

Model Temperature Range Package Description Package Option

AD829AR –40°C to +125°C 8-Lead Plastic SOIC R-8
AD829AR-REEL –40°C to +125°C 8-Lead Plastic SOIC R-8
AD829AR-REEL7 –40°C to +125°C 8-Lead Plastic SOIC R-8
AD829ARZ* –40°C to +125°C 8-Lead Plastic SOIC R-8
AD829ARZ-REEL* –40°C to +125°C 8-Lead Plastic SOIC R-8
AD829ARZ-REEL7* –40°C to +125°C 8-Lead Plastic SOIC R-8
AD829JN 0°C to 70°C 8-Lead Plastic PDIP N-8
AD829JR 0°C to 70°C 8-Lead Plastic SOIC R-8
AD829JR-REEL 0°C to 70°C 8-Lead Plastic SOIC R-8
AD829JR-REEL7 0°C to 70°C 8-Lead Plastic SOIC R-8
AD829AQ –40°C to +125°C 8-Lead CERDIP Q-8
AD829SQ –55°C to +125°C 8-Lead CERDIP Q-8
AD829SQ/883B –55°C to +125°C 8-Lead CERDIP Q-8
5962-9312901MPA –55°C to +125°C 8-Lead CERDIP Q-8
AD829SE/883B –55°C to +125°C 20-Lead LCC E-20A
5962-9312901M2A –55°C to +125°C 20-Lead LCC E-20A
AD829JCHIPS Die
AD829SCHIPS Die

*Z = Pb-free part.

AD829

REV. G

–5–

AD829–Typical Performance Characteristics

(ⴗC)

(ⴗC)

OUTPUT VOLTAGE SWING (V p–p)

30

25

20

15

10

5

0

10 100

1k 10k

LOAD RESISTANCE (⍀)

ⴞ5 V
SUPPLIES

ⴞ15 V
SUPPLIES

(Hz)

20

15

+V

OUT

10

–V

OUT

5

INPUT COMMON-MODE RANGE (V)

0

02051015

SUPPLY VOLTAGE (ⴞV)

TPC 1. Input Common-Mode
Range vs. Supply Voltage

6.0

5.5

5.0

4.5

QUIESCENT CURRENT (mA)

20

15

10

VOLTAGE (V)

5

MAGNITUDE OF THE OUTPUT

0

02051015

SUPPLY VOLTAGE (±V)

+V

OUT

–V

R

TPC 2. Output Voltage Swing
vs. Supply Voltage

5–

–

4

VS = ⴞ5V, ⴞ15V

–

3

INPUT BIAS CURRENT (␮A)

OUT

LOAD

= 1k⍀

TPC 3. Output Voltage Swing
vs. Resistive Load

100

10

1

0.1

0.01

AV = +20
C

COMP

= 0pF

AV = +1
C

COMP

= 68pF

4.0
02051015

SUPPLY VOLTAGE (ⴞV)

TPC 4. Quiescent Current vs.
Supply Voltage

7

6

5

4

QUIESCENT CURRENT (mA)

3

60–20–02040 60 80 100 14040–

VS = ⴞ15V

VS = ⴞ5V

120

TEMPERATURE

TPC 7. Quiescent Current vs.
Temperature

2–

40–

60–20–02040 60 80 100 140

TEMPERATURE (ⴗC)

TPC 5. Input Bias Current vs.
Temperature

40

NEGATIVE

35

30

25

20

SHORT CIRCUIT CURRENT LIMIT (mA)

15

60–20–02040 60 80 100 14040–

CURRENT LIMIT

POSITIVE

CURRENT LIMIT

VS = ⴞ5V

AMBIENT TEMPERATURE

TPC 8. Short-Circuit Current
Limit vs. Temperature

120

120

CLOSED-LOOP OUTPUT IMPEDANCE (⍀)

0.001
1k 10k 100k 1M 10M 100M

FREQUENCY

TPC 6. Closed-Loop Output
Impedance vs. Frequency

65

VS = ±15V

= +20

A

V

= 0pF

C

60

55

50

–3 dB BANDWIDTH (MHz)

45

COMP

60–20–02040 60 80 100 14040–

TEMPERATURE (ⴗC)

TPC 9. –3 dB Bandwidth vs.
Temperature

120

REV. G–6–

AD829

(Hz)

)

(

)

(Hz)

10

8

6

4

2

0

020406080100 120 160

1%

1%

140

2–

4–

6–

8–

0.1%

ERROR
A

V

= –19

C

COMP

= 0pF

–10

OUTPUT SWING FROM 0 TO ⴞV

SETTLING TIME (ns)

0.1%

)

120

100

80

60

40

OPEN-LOOP GAIN (dB)

20

0
100 1k 10k 100k 1M 10M 100M

GAIN
ⴞ5V
SUPPLIES
500⍀ LOAD

C

COMP

FREQUENCY (Hz)

= 0pF

GAIN
ⴞ15V
SUPPLIES
1k⍀ LOAD

PHASE

TPC 10. Open-Loop Gain and
Phase Margin vs. Frequency

120

100

80

60

CMRR (dB)

C

= 0pF

40

COMP

100

80

60

40

20

PHASE (Degrees)

0

–20

105

100

95

90

85

OPEN-LOOP GAIN (dB)

80

75

10 100

VS = ⴞ15V

VS = ⴞ5V

1k

LOAD RESISTANCE (⍀)

TPC 11. Open-Loop Gain vs.
Resistive Load

30

25

20

15

VS = ±5V

= 500⍀

R

L

10

= +20

A

V

OUTPUT VOLTAGE (V p–p)

C

5

COMP

= 0pF

VS = ±15V

= 1k⍀

R

L

= +20

A

V

C

COMP

= 0pF

10k

120

+

SUPPLY

100

80

SUPPLY–

60

PSRR (dB)

40

C

= 0pF

COMP

20

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

FREQUENCY (Hz)

TPC 12. Power Supply Rejection
Ratio (PSRR) vs. Frequency

20

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

FREQUENCY

TPC 13. Common-Mode
Rejection Ratio vs. Frequency

–70

–75

–80

–85

–90

THD (dB)

–95

–100

–105

–110

100 300 1k 3k 10k 30k 100k

VIN = 3V RMS

= –1

A

V

C

COMP

C

LOAD

RL = 500⍀

RL = 2k⍀

FREQUENCY (Hz

TPC 16. Total Harmonic
Distortion (THD) vs. Frequency

REV. G

= 30pF

= 100pF

0

1

INPUT FREQUENCY

10 100

MHz

TPC 14. Large Signal Frequency
Response

–20

THIRD HARMONIC

SECOND HARMONIC

1.0M

FREQUENCY

1.5M

–30

–40

THD (dB)

–50

–60

–70

0

VIN = 2.24V RMS

= –1

A

V

= 250⍀

R

L

= 0

C

LOAD

= 30pF

C

COMP

500k

TPC 17. Second and Third
Harmonic Distortion vs.
Frequency

–7–

2.0M

TPC 15. Output Swing and Error vs.
Settling Time

5

4

3

2

1

INPUT VOLTAGE NOISE (nV/ Hz)

0

10 100 1k 10k 100k

FREQUENCY (Hz

1M 10M

TPC 18. Input Voltage Noise
Spectral Density

AD829

(ⴗC)

(V)

(

)

+V

S

0.1␮F

C

COMP

(EXTERNAL)

–V

S

0.1␮F

OFFSET

NULL

ADJUST

20k⍀

AD829

400

350

300

250

200

SLEW RATE (V/␮s)

150

100

AV = +20
SLEW RATE 10% to 90%

VS = ⴞ15V

60–20–02040 60 80 100 14040–

RISE

FALL

RISE

FALL

VS = ⴞ5V

120

TEMPERATURE

TPC 19. Slew Rate vs. Temperature

HP8130A

5ns RISE TIME

0.05

0.04

DIFFERENTIAL PHASE (Degrees)

0.03
ⴞ5 ⴞ10 ⴞ15

SUPPLY VOLTAGE

0.043ⴗ

TPC 20. Differential Gain and Phase
vs. Supply

C

COMP

+15V

AD829

15pF

0.1␮F

50⍀

CABLE

0.1␮F

50⍀

DIFF GAIN

DIFF PHASE

5pF

50⍀

300⍀

0.03

0.02

0.01

CABLE

Percent

DIFFERENTIAL GAIN

Figure 2. Offset Null and
External Shunt Compensation
Connections

50⍀

TEKTRONIX
TYPE 7A24
PREAMP

50⍀

–15V

300⍀

Figure 3a. Follower Connection. Gain = +2

Figure 3b. Gain-of-2 Follower

Large Signal Pulse Response

Figure 3c. Gain-of-2 Follower Small
Signal Pulse Response

REV. G–8–

AD829

HP8130A

5ns RISE TIME

50⍀

CABLE

45⍀

5⍀

100⍀

C

COMP

+15V

AD829

–15V

= 0pF

0.1␮F

0.1␮F

1pF

2k⍀

105⍀

Figure 4a. Follower Connection. Gain = +20

FET PROBE

TEKTRONIX

TYPE 7A24

PREAMP

Figure 4b. Gain-of-20 Follower
Large Signal Pulse Response

50⍀

HP8130A

5ns RISE TIME

CABLE

Figure 5a. Unity Gain Inverter Connection

50⍀

300⍀

300⍀

+15V

AD829

–15V

5pF

0.1␮F

0.1␮F

C

15pF

COMP

Figure 4c. Gain-of-20 Follower

Small Signal Pulse Response

50⍀

50⍀

CABLE

TEKTRONIX
TYPE 7A24
PREAMP

50⍀

REV. G

Figure 5b. Unity Gain Inverter

Large Signal Pulse Response

Figure 5c. Unity Gain Inverter

Small Signal Pulse Response

–9–

AD829

THEORY OF OPERATION

The AD829 is fabricated on Analog Devices’ proprietary comple­mentary bipolar (CB) process, which provides PNP and NPN
transistors with similar f
the AD829 input stage consists of an NPN differential pair in
which each transistor operates at 600 µA collector current. This
gives the input devices a high transconductance, which in turn
gives the AD829 a low noise figure of 2 nV/

The input stage drives a folded cascode that consists of a fast
pair of PNP transistors. These PNPs drive a current mirror that
provides a differential-input-to-single-ended-output conversion.
The high speed PNPs are also used in the current-amplifying
output stage, which provides high current gain of 40,000. Even
under conditions of heavy loading, the high f
PNPs, produced using the CB process, permits cascading two
stages of emitter followers while maintaining 60° phase margin
at closed-loop bandwidths greater than 50 MHz.

Two stages of complementary emitter followers also effectively
buffer the high impedance compensation node (at the C
from the output so the AD829 can maintain a high dc open-loop
gain, even into low load impedances: 92 dB into a 150 Ω load and
100 dB into a 1 kΩ load. Laser trimming and PTAT biasing
ensure low offset voltage and low offset voltage drift, enabling
the user to eliminate ac coupling in many applications.

For added flexibility, the AD829 provides access to the internal
frequency compensation node. This allows the user to customize
frequency response characteristics for a particular application.

Unity gain stability requires a compensation capacitance of 68 pF
(Pin 5 to ground), which will yield a small signal bandwidth of
66 MHz and slew rate of 16 V/µs. The slew rate and gain band-
width product will vary inversely with compensation capacitance.
Table I and Figure 8 show the optimum compensation capacitance
and the resulting slew rate for a desired noise gain. For gains
between 1 and 20, C
bandwidth relatively constant. The minimum gain that will still
provide stability depends on the value of external compensation
capacitance.

An RC network in the output stage (Figure 6) completely
removes the effect of capacitive loading when the amplifier is
compensated for closed-loop gains of 10 or higher. At low frequen­cies, and with low capacitive loads, the gain from the compensation
node to the output is very close to unity. In this case, C is
bootstrapped and does not contribute to the compensation
capacitance of the device. As the capacitive load is increased, a
pole is formed with the output impedance of the output stage
this reduces the gain, and subsequently, C is incompletely boot­strapped. Therefore, some fraction of C contributes to the
compensation capacitance, and the unity gain bandwidth falls. As
the load capacitance is further increased, the bandwidth continues
to fall and the amplifier remains stable.

Externally Compensating the AD829

The AD829 is stable with no external compensation for noise
gains greater than 20. For lower gains, two different methods of
frequency compensating the amplifier can be used to achieve
closed-loop stability: shunt and current feedback compensation.

s of 600 MHz. As shown in Figure 6,

T

√

Hz @ 1 kHz.

s of the NPN and

T

COMP

can be chosen to keep the small signal

COMP

pin)

+V

S

15⍀

IN+

1.2mA

IN–

OFFSET NULL

C

COMP

C

12.5pF

R

500⍀

15⍀

OUTPUT

–V

S

Figure 6. Simplified Schematic

Shunt Compensation

Figures 7 and 8 show that shunt compensation has an external
compensation capacitor, C

, connected between the com-

COMP

pensation pin and ground. This external capacitor is tied in
parallel with approximately 3 pF of internal capacitance at the
compensation node. In addition, a small capacitance, C

LEAD

,
in parallel with resistor R2, compensates for the capacitance at
the amplifier’s inverting input.

R2

C

LEAD

+V

S

0.1␮F

0.1␮F

C

COMP

1k⍀

V

OUT

50⍀

COAX

CABLE

V

IN

50⍀

R1

AD829

–V

S

Figure 7. Inverting Amplifier Connection Using External
Shunt Compensation

+V

S

C

0.1␮F

0.1␮F

COMP

V

OUT

R2

1k⍀

C

LEAD

R1

50⍀

CABLE

V

IN

50⍀

AD829

–V

S

Figure 8. Noninverting Amplifier Connection Using
External Shunt Compensation

REV. G–10–

Table I. Component Selection for Shunt Compensation

(

␮

)

Slew

Follower Inverter R1 R2 C

C

L

COMP

Rate –3 dB Small Signal

Gain Gain (⍀)(⍀) (pF) (pF) (V/␮s) Bandwidth (MHz)

1Open 100 0 68 16 66
2–11 k1 k5 25 38 71
5–4511 2.0 k 1 7 90 76
10 –9 226 2.05 k 0 3 130 65
20 –19 105 2 k 0 0 230 55
25 –24 105 2.49 0 0 230 39
100 –99 20 2 k 0 0 230 7.5

AD829

Table I gives the recommended C

COMP

and C

LEAD

values, as
well as the corresponding slew rates and bandwidth. The capacitor
values were selected to provide a small signal frequency response
with less than 1 dB of peaking and less than 10% overshoot. For
this table, supply voltages of ±15 V should be used. Figure 9 is
a graphical extension of the table that shows the slew rate/gain
trade-off for lower closed-loop gains, when using the shunt
compensation scheme.

100

C

COMP

(pF)

10

COMP

C

1

1 10010

Figure 9. Value of C

SLEW RATE

VS = ⴞ15V

NOISE GAIN

and Slew Rate vs. Noise Gain

COMP

1k

s

V/

100

SLEW RATE

10

Current Feedback Compensation

Bipolar, nondegenerated, single pole, and internally compensated
amplifiers have their bandwidths defined as

fT=

2 π r

1

eCCOMP

=

2 π

kT

I

C

COMP

q

where

f

is the unity gain bandwidth of the amplifier.

T

I is the collector current of the input transistor.

is the compensation capacitance.

C

COMP

r

is the inverse of the transconductance of the input transistors.

e

kT/q approximately equals 26 mV @ 27°C.

Since both f

and slew rate are functions of the same variables,

T

the dynamic behavior of an amplifier is limited. Since

Slew Rate =

C

2I

COMP

then

Slew Rate

f

T

= 4 π

kT

q

This shows that the slew rate will be only 0.314 V/µs for every
MHz of bandwidth. The only way to increase slew rate is to
increase the f

, and that is difficult because of process limitations.

T

Unfortunately, an amplifier with a bandwidth of 10 MHz can
only slew at 3.1 V/µs, which is barely enough to provide a full
power bandwidth of 50 kHz.

The AD829 is especially suited to a new form of compensation
that allows for the enhancement of both the full power band­width and slew rate of the amplifier. The voltage gain from the
inverting input pin to the compensation pin is large; therefore, if
a capacitance is inserted between these pins, the amplifier’s
bandwidth becomes a function of its feedback resistor and the
capacitance. The slew rate of the amplifier is now a function of
its internal bias (2I) and the compensation capacitance.

Since the closed-loop bandwidth is a function of R

and C

F

COMP

(Figure 10), it is independent of the amplifier closed-loop gain,
as shown in Figure 12. To preserve stability, the time constant

and C

of R

F

65 MHz. For example, with C

needs to provide a bandwidth of less than

COMP

= 15 pF and RF = 1 kΩ, the

COMP

small signal bandwidth of the AD829 is 10 MHz. Figure 11 shows
that the slew rate is in excess of 60 V/µs. As shown in Figure 12,
the closed-loop bandwidth is constant for gains of –1 to –4; this is
a property of current feedback amplifiers.

R

F

C

COMP

0.1␮F
+V

AD829

–V

S

S

V

OUT

R

0.1␮F
1k⍀

L

50⍀

COAX

CABLE

V

IN

*RECOMMENDED VALUE

OF C

<7pF

7pF

50⍀

COMP

R1

C1*

FOR C

0pF
15pF

IN4148

1

C

SHOULD NEVER EXCEED

COMP

15pF FOR THIS CONNECTION

Figure 10. Inverting Amplifier Connection Using Current
Feedback Compensation

REV. G

–11–

AD829

)

Figure 11. Large Signal Pulse Response of Inverting
Amplifier Using Current Feedback Compensation,

= 15 pF, C1 = 15 pF, RF = 1 kΩ, R1 = 1 k

C

COMP

15

GAIN = –4

12

9

GAIN = –2

6

–3dB @ 9.6MHz

3

GAIN = –1

0

–3

–6

CLOSED-LOOP GAIN (dB)

–9

–12

–15

–3dB @ 10.2MHz

VIN = –30dBM

= ⴞ15V

V

S

R

= 1k⍀

L

= 1k⍀

R

F

C

= 15pF

COMP

C

= 15pF

1

100k 100M

1M 10M

FREQUENCY (Hz

–3dB @ 8.2MHz

Ω

Figure 12. Closed-Loop Gain vs. Frequency for the Circuit
of Figure 9

Figure 13 is an oscilloscope photo of the pulse response of a
unity gain inverter that has been configured to provide a small
signal bandwidth of 53 MHz and a subsequent slew rate of
180 V/µs; resistor R

= 3 kΩ and capacitor C

F

= 1 pF. Figure 14

COMP

shows the excellent pulse response as a unity gain inverter, this
using component values of R

F

= 1 kΩ and C

COMP

= 4 pF.

Figures 15 and 16 show the closed-loop frequency response of the
AD829 for different closed-loop gains and different supply voltages.

If a noninverting amplifier configuration using current feedback
compensation is needed, the circuit of Figure 17 is recommended.
This circuit provides a slew rate twice that of the shunt com­pensated noninverting amplifier of Figure 18 at the expense of
gain flatness. Nonetheless, this circuit delivers 95 MHz bandwidth
with ±1 dB flatness into a back terminated cable, with a differ­ential gain error of only 0.01% and a differential phase error of
only 0.015° at 4.43 MHz.

Figure 13. Large Signal Pulse Response of the Inverting
Amplifier Using Current Feedback Compensation,
C

= 1 pF, RF = 3 kΩ, R1 = 3 k

COMP

Ω

Figure 14. Small Signal Pulse Response of Inverting
Amplifier Using Current Feedback Compensation,

= 4 pF, RF = 1 kΩ, R1 = 1 k

C

COMP

15

GAIN = –4

12

9

GAIN = –2

6

3

GAIN = –1

0

–3

VS = ⴞ15V

–6

CLOSED-LOOP GAIN (dB)

–9

–12

–15

= 1k⍀

R

L

= 1k⍀

R

F

= –30dBM

V

IN

110

Ω

C

= 2pF

COMP

C

= 3pF

COMP

C

= 4pF

COMP

FREQUENCY (MHz)

100

Figure 15. Closed-Loop Frequency Response for the
Inverting Amplifier Using Current Feedback Compensation

REV. G–12–

AD829

)

–17

–20

–23

–26

–29

–32

–35

OUTPUT LEVEL (dB)

–38

–41

–44

–47

110

VIN = –20dBM

= 1k⍀

R

L

= 1k⍀

R

F

GAIN = –1

= 4pF

C

COMP

FREQUENCY (MHz

ⴞ5V

ⴞ15V

100

Figure 16. Closed-Loop Frequency Response vs. Supply
for the Inverting Amplifier Using Current Feedback
Compensation

A Low Error Video Line Driver

The buffer circuit shown in Figure 18 will drive a back-terminated
75 Ω video line to standard video levels (1 V p-p) with 0.1 dB
gain flatness to 30 MHz with only 0.04° and 0.02% differential
phase and gain at the 4.43 MHz PAL color subcarrier frequency.
This level of performance, which meets the requirements for high
definition video displays and test equipment, is achieved using
only 5 mA quiescent current.

A High Gain, Video Bandwidth, Three Op Amp In Amp

Figure 19 shows a three op amp instrumentation amplifier circuit
that provides a gain of 100 at video bandwidths. At a circuit gain
of 100, the small signal bandwidth equals 18 MHz into a FET
probe. Small signal bandwidth equals 6.6 MHz with a 50 Ω load.
The 0.1% settling time is 300 ns.

3pF

+V

IN

(G = 20)

A1

2pF to 8pF

SETTLING TIME

AC CMR ADJUST

+15V

0.1␮F

50⍀

COAX

CABLE

V

IN

AD829

50⍀

3pF

–15V

0.1␮F

C

COMP

50⍀

2k⍀

2k⍀

50⍀

COAX

CABLE

50⍀

V

OUT

Figure 17. Noninverting Amplifier Connection Using
Current Feedback Compensation

+15V

0.1␮F

75⍀

V

IN

C

30pF

COMP

AD829

–15V

0.1␮F

75⍀

75⍀

300⍀

300⍀

COAX

CABLE

OPTIONAL
2pF to 7pF
FLATNESS
TRIM

75⍀

V

OUT

Figure 18. A Video Line Driver with a Flatness over
Frequency Adjustment

The input amplifiers operate at a gain of 20, while the output
op amp runs at a gain of 5. In this circuit, the main bandwidth
limitation is the gain/bandwidth product of the output amplifier.
Extra care should be taken while breadboarding this circuit, since
even a couple of extra picofarads of stray capacitance at the com­pensation pins of A1 and A2 will degrade circuit bandwidth.

210⍀

+V

IN

REV. G

970⍀

DC CMR
ADJUST

50⍀

A3

1k⍀

AD848

4000⍀

(

(G = 5)

R

G

+ 1(5

2k⍀

+15V

COMM

–15V

10␮F

10␮F

INPUT

FREQUENCY

100 Hz
1 MHz
10 MHz

0.1␮F

0.1␮F

+V

–V

CMRR

64.6dB

44.7dB

23.9dB

S

S

1␮F

1␮F

0.1␮F

0.1␮F

PIN 7

EACH
AMPLIFIER

PIN 4

AD829

2k⍀

1pF

R

G

1pF

2k⍀

200⍀

200⍀

3pF

AD829

A2

(G = 20)

3pF

CIRCUIT GAIN =

Figure 19. A High Gain, Video Bandwidth, Three Op Amp In Amp Circuit

–13–

AD829

OUTLINE DIMENSIONS

8-Lead Plastic Dual In-Line Package [PDIP]

(N-8)

Dimensions shown in inches and (millimeters)

0.375 (9.53)

0.365 (9.27)

0.355 (9.02)

8

1

0.100 (2.54)

0.180

(4.57)

MAX

0.150 (3.81)

0.130 (3.30)

0.110 (2.79)

0.022 (0.56)

0.018 (0.46)

0.014 (0.36)

CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN

COMPLIANT TO JEDEC STANDARDS MO-095AA

BSC

5

4

0.295 (7.49)

0.285 (7.24)

0.275 (6.98)

0.015
(0.38)
MIN

SEATING
PLANE

0.060 (1.52)

0.050 (1.27)

0.045 (1.14)

0.325 (8.26)

0.310 (7.87)

0.300 (7.62)

0.150 (3.81)

0.135 (3.43)

0.120 (3.05)

0.015 (0.38)

0.010 (0.25)

0.008 (0.20)

8-Lead Standard Small Outline Package [SOIC]

Narrow Body

(R-8)

Dimensions shown in millimeters and (inches)

5.00 (0.1968)

4.80 (0.1890)

4.00 (0.1574)

3.80 (0.1497)

0.25 (0.0098)

0.10 (0.0040)

COPLANARITY

0.10

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

85

1.27 (0.0500)

SEATING

PLANE

COMPLIANT TO JEDEC STANDARDS MS-012AA

BSC

6.20 (0.2440)

5.80 (0.2284)

41

1.75 (0.0688)

1.35 (0.0532)

0.51 (0.0201)

0.31 (0.0122)

0.25 (0.0098)

0.17 (0.0067)

0.50 (0.0196)

0.25 (0.0099)

8ⴗ
0ⴗ

1.27 (0.0500)

0.40 (0.0157)

ⴛ 45ⴗ

20-Terminal Ceramic Leadless Chip Carrier [LCC]

(E-20A)

Dimensions shown in inches and (millimeters)

1

VIEW

0.150 (3.81)
BSC

0.200 (5.08)
REF

0.100 (2.54) REF

0.015 (0.38)
MIN

3

4

0.028 (0.71)

0.022 (0.56)

0.050 (1.27)

8

BSC

9

45 TYP

0.075 (1.91)

0.095 (2.41)

0.075 (1.90)

0.011 (0.28)

0.007 (0.18)
R TYP

0.075 (1.91)
REF

0.055 (1.40)

0.045 (1.14)

REF

19

18

14

13

20

BOTTOM

0.100 (2.54)

0.064 (1.63)

0.358 (9.09)

0.342 (8.69)
SQ

CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETERS DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN

0.358
(9.09)

MAX

0.088 (2.24)

0.054 (1.37)

SQ

8-Lead Ceramic Dual In-Line Package [CERDIP]

(Q-8)

Dimensions shown in inches and (millimeters)

0.005 (0.13)

PIN 1

0.200 (5.08)
MAX

0.200 (5.08)

0.125 (3.18)

0.023 (0.58)

0.014 (0.36)

CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETERS DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN

0.055 (1.40)

MIN

0.100 (2.54) BSC

0.405 (10.29) MAX

MAX

85

1

4

0.070 (1.78)

0.030 (0.76)

0.310 (7.87)

0.220 (5.59)

0.060 (1.52)

0.015 (0.38)

0.150 (3.81)
MIN

SEATING
PLANE

0.320 (8.13)

0.290 (7.37)

15

0

0.015 (0.38)

0.008 (0.20)

REV. G–14–

AD829

Revision History

Location Page

4/04—Data Sheet changed from REV. F to REV. G.

Added new Figure 1 and renumbered all figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Changes to ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Updated Table I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Updated Figure 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Updated Figure 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Updated OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2/03—Data Sheet changed from REV. E to REV. F.

Renumbered Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Universal

Changes made to PRODUCT HIGHLIGHTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Changes made to SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Changes made to ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Changes made to ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Updated OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

REV. G

–15–

C00880–0–4/04(G)

–16–