ANALOG DEVICES AD8138-EP Service Manual

Low Distortion

A

V

V

FEATURES

Adjustable output common-mode voltage
Low harmonic distortion

−94 dBc SFDR @ 5 MHz

−85 dBc SFDR @ 20 MHz

−3 dB bandwidth of 320 MHz, G = +1
Fast settling to 0.01% of 16 ns
Fast overdrive recovery of 4 ns
Low input voltage noise of 5 nV/√Hz
Low power 90 mW on 5 V

ENHANCED PRODUCT FEATURES

Supports defense and aerospace applications (AQEC)
Extended temperature range −55ºC to +105°C
Controlled manufacturing baseline
One assembly/test site
One fabrication site
Enhanced product change notification
Qualification data available on request

APPLICATIONS

ADC drivers
Single-ended-to-differential converters
IF and baseband gain blocks
Differential buffers
Line drivers

GENERAL DESCRIPTION

The AD8138-EP is a major advancement over op amps for
differential signal processing. The AD8138-EP can be used
as a single-ended-to-differential amplifier or as a differential-to­differential amplifier. The AD8138-EP is as easy to use as an op
amp and greatly simplifies differential signal amplification and
driving. Manufactured on Analog Devices, Inc., proprietary XFCB
bipolar process, the AD8138-EP has a −3 dB bandwidth of 320 MHz
and delivers a differential signal with the lowest harmonic distortion
available in a differential amplifier. The AD8138-EP has a unique
internal feedback feature that provides balanced output gain and
phase matching, suppressing even order harmonics. The internal
feedback circuit also minimizes any gain error that would be
associated with the mismatches in the external gain setting resistors.

Differential ADC Driver

AD8138-EP

PIN CONFIGURATION

D8138-EP

–IN

1

V

2

OCM

V+

3

+OUT

4

NC = NO CONNECT

Figure 1.

TYPICAL APPLICATION CIRCUIT

5

499Ω

499Ω

IN

The AD8138-EP’s differential output helps balance the input to
the differential ADCs, maximizing the performance of the ADC.

The AD8138-EP eliminates the need for a transformer with
high performance ADCs, preserving the low frequency and dc
information. The common-mode level of the differential output
is adjustable by a voltage on the V
the input signals for driving single-supply ADCs. Fast overload
recovery preserves sampling accuracy.

The AD8138-EP distortion performance makes it an ideal ADC
driver for communication systems, with distortion performance
good enough to drive state-of-the-art 10-bit to 16-bit converters
at high frequencies. The AD8138-EP’s high bandwidth and IP3 also
make it appropriate for use as a gain block in IF and baseband
signal chains. The AD8138-EP offset and dynamic performance
make it well suited for a wide variety of signal processing and
data acquisition applications. The AD8138-EP is available in the
MSOP package for operation over −55°C to +105°C temperatures.

Full details about this enhanced product are available in the

AD8138 data sheet, which should be consulted in conjunction

with this data sheet.

499Ω

V

OCM

+

AD8138-EP

–

499Ω

Figure 2.

+IN

8

NC

7

V–

6

–OUT

5

08997-001

5V

AVDD DVDD

AIN

ADC

AIN

pin, easily level-shifting

OCM

AVSS

V

REF

DIGITAL
OUTPUTS

08997-002

Rev. 0

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: [phone] www.analog.com
Fax: [phone] ©2010 Analog Devices, Inc. All rights reserved.

AD8138-EP

TABLE OF CONTENTS

Features .............................................................................................. 1

V

to ±OUT Specifications ......................................................6

OCM

Enhanced Product Features ............................................................ 1

Applications ....................................................................................... 1 

General Description ......................................................................... 1

Pin Configuration ............................................................................. 1

Typical Application Circuit ............................................................. 1

Revision History ............................................................................... 2

Specifications ..................................................................................... 3

±DIN to ±OUT Specifications ...................................................... 3

V

to ±OUT Specifications ..................................................... 4

OCM

±DIN to ±OUT Specifications ...................................................... 5

REVISION HISTORY

4/10—Revision 0: Initial Version

Absolute Maximum Ratings ............................................................7

Thermal Resistance .......................................................................7

Maximum Power Dissipation ......................................................7

ESD Caution...................................................................................7

Maximum Output Voltage Swing ................................................8

Pin Configuration and Function Descriptions ..............................9

Outline Dimensions ....................................................................... 10

Ordering Guide .......................................................................... 10

Rev. 0 | Page 2 of 12

AD8138-EP

SPECIFICATIONS

±DIN TO ±OUT SPECIFICATIONS

At 25°C, VS = ±5 V, V
differential outputs, unless otherwise noted.

Table 1.

Parameter Conditions Min Typ Max Unit

DYNAMIC PERFORMANCE

−3 dB Small Signal Bandwidth V

T
V
Bandwidth for 0.1 dB Flatness V
Large Signal Bandwidth V
Slew Rate V
Settling Time 0.01%, V
Overdrive Recovery Time VIN = 5 V to 0 V step, G = +2 4 ns

NOISE/HARMONIC PERFORMANCE

Second Harmonic V
V
V
Third Harmonic V
V
V
IMD 20 MHz −77 dBc
IP3 20 MHz 37 dBm
Voltage Noise (RTI) f = 100 kHz to 40 MHz 5 nV/√Hz
Input Current Noise f = 100 kHz to 40 MHz 2 pA/√Hz

INPUT CHARACTERISTICS

Offset Voltage V
T
Input Bias Current 3.5 7 μA
T
Input Resistance Differential 6 MΩ
Common mode 3 MΩ
Input Capacitance 1 pF
Input Common-Mode Voltage −4.7 to +3.4 V
CMRR ΔV
T

OUTPUT CHARACTERISTICS

Output Voltage Swing2 Maximum ΔV
Output Balance Error ΔV

1

Specified to ±6 sigma over the −55°C to +105°C operating temperature range.

2

Output swing capabilities vary over operating temperature. See for more information. Figure 4

= 0 V, G = +1, R

OCM

= 500 Ω, unless otherwise noted. All specifications refer to single-ended input and

L, dm

= 0.5 V p-p, CF = 0 pF 290 320 MHz

OUT

MIN

OUT

OUT

OUT

OUT

OUT

OUT

OUT

OUT

OUT

OUT

OS, dm

MIN

MIN

OUT, dm

MIN

OUT, cm

1

to T

256 MHz

MAX

= 0.5 V p-p, CF = 1 pF 225 MHz
= 0.5 V p-p, CF = 0 pF 30 MHz
= 2 V p-p, CF = 0 pF 265 MHz
= 2 V p-p, CF = 0 pF 1150 V/μs

= 2 V p-p, CF = 1 pF 16 ns

OUT

= 2 V p-p, 5 MHz, R
= 2 V p-p, 20 MHz, R
= 2 V p-p, 70 MHz, R
= 2 V p-p, 5 MHz, R
= 2 V p-p, 20 MHz, R
= 2 V p-p, 70 MHz, R

= V

to T

to T

to T

/2; V

OUT, dm

1

−4.8 +4.8 mV

MAX

variation −0.01 μA/°C

MAX

/ΔV

; ΔV

IN, cm

1

−69 dB

MAX

; single-ended output 7.75 V p-p

OUT

/ΔV

OUT, dm

; ΔV

= 800 Ω −94 dBc

L, dm

= 800 Ω −87 dBc

L, dm

= 800 Ω −62 dBc

L, dm

= 800 Ω −114 dBc

L, dm

= 800 Ω −85 dBc

L, dm

= 800 Ω −57 dBc

L, dm

= V

= V

DIN+

DIN−

= ±1 V, −77 −70 dB

IN, cm

= 1 V −66 dB

OUT, dm

= 0 V −2.5 ±1 +2.5 mV

OCM

Rev. 0 | Page 3 of 12

AD8138-EP

V

TO ±OUT SPECIFICATIONS

OCM

At 25°C, VS = ±5 V, V
differential outputs, unless otherwise noted.

Table 2.

Parameter Conditions Min Typ Max Unit

DYNAMIC PERFORMANCE

−3 dB Bandwidth 250 MHz

Slew Rate 330 V/μs
INPUT VOLTAGE NOISE (RTI) f = 0.1 MHz to 100 MHz 17 nV/√Hz
DC PERFORMANCE

Input Voltage Range ±3.8 V

Input Resistance 200 kΩ

Input Offset Voltage V

T

Input Bias Current 0.5 μA

V

CMRR ΔV

OCM

Gain ΔV
POWER SUPPLY

Operating Range ±1.4 ±5.5 V

Quiescent Current 18 20 23 mA

T

Power Supply Rejection Ratio ΔV
OPERATING TEMPERATURE RANGE −55 +105 °C

1

Specified to ±6 sigma over the −55°C to +105°C operating temperature range.

= 0 V, G = +1, R

OCM

= 500 Ω, unless otherwise noted. All specifications refer to single-ended input and

L, dm

OS, cm

MIN

OUT, dm

OUT, cm

MIN

OUT, dm

= V

to T

to T

; V

= V

= V

OUT, cm

DIN+

1

−10.2 +10.2 mV

MAX

/ΔV

; ΔV

OCM

/ΔV

; ΔV

OCM

1

13.2 mA

MAX

DIN–

= ±1 V −75 dB

OCM

= ±1 V, T

OCM

/ΔVS; ΔVS = ±1 V, T

= 0 V −3.5 ±1 +3.5 mV

OCM

1

to T

0.9955 1 1.0045 V/V

MAX

1

−90 −70 dB

MIN

MIN

to T

MAX

Rev. 0 | Page 4 of 12