Analog Devices AD8344 Service Manual

Active Receive Mixer

FEATURES

Broadband RF port: 400 MHz to 1.2 GHz
Conversion gain: 4.5 dB
Noise figure: 10.5 dB
Input IP3: 24 dBm
Input P1dB: 8.5 dBm
LO drive: 0 dBm
External control of mixer bias for low power operation
Single-ended, 50 Ω RF and LO input ports
Single-supply operation: 5 V @ 84 mA
Power-down mode
Exposed paddle LFCSP: 3 mm × 3 mm

APPLICATIONS

Cellular base station receivers
ISM receivers
Radio links
RF Instrumentation

400 MHz to 1.2 GHz

AD8344

FUNCTIONAL BLOCK DIAGRAM

VPDC12PWDN11EXRB10COMM

13

COMM

RFCM

RFIN

VPMX

BIAS

14

15

16

1

2

VPLO

Figure 1.

LOCM

3

LOIN

9

4

COMM

8

7

6

5

COMM

IFOP

IFOM

COMM

04826-0-001

GENERAL DESCRIPTION

The AD8344 is a high performance, broadband active mixer. It
is well suited for demanding receive-channel applications that
require wide bandwidth on all ports and very low intermodula­tion distortion and noise figure.

The AD8344 provides a typical conversion gain of 4.5 dB at
890 MHz. The integrated LO driver supports a 50 Ω input
impedance with a low LO drive level, helping to minimize
external component count.

The single-ended 50 Ω broadband RF port allows for easy
interfacing to both active devices and passive filters. The RF
input accepts input signals as large as 1.7 V p-p or 8.5 dBm
(re: 50 Ω) at P1dB.

The open-collector differential outputs provide excellent
balance and can be used with a differential filter or IF amplifier,
such as the AD8369 or AD8351. These outputs may also be con­verted to a single-ended signal through the use of a matching
network or a transformer (balun). When centered on the VPOS
supply voltage, each of the differential outputs may swing

2.5 V p-p.

The AD8344 is fabricated on an Analog Devices proprietary,
high performance SiGe IC process. The AD8344 is available
in a 16-lead LFCSP package. It operates over a −40°C to +85°C
temperature range. An evaluation board is also available.

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]
Fax: [phone] © 2004 Analog Devices, Inc. All rights reserved.

www.analog.com

AD8344

TABLE OF CONTENTS

Specifications..................................................................................... 3

IF Port.......................................................................................... 14

AC Performance ............................................................................... 4

Absolute Maximum Ratings............................................................ 5

ESD Caution.................................................................................. 5

Pin Configuration and Function Descriptions............................. 6

Typical Performance Characteristics............................................. 7

Circuit Description......................................................................... 13

AC Interfaces ................................................................................... 14

REVISION HISTORY

6/04—Revision 0: Initial Version

LO Considerations ..................................................................... 15

Bias Resistor Selection ............................................................... 16

Conversion Gain and IF Loading............................................. 16

Low IF Frequency Operation.................................................... 17

Evaluation Board ............................................................................ 18

Outline Dimensions....................................................................... 20

Ordering Guide .......................................................................... 20

Rev. 0 | Page 2 of 20

AD8344

SPECIFICATIONS

VS = 5 V, TA = 25°C, fRF = 890 MHz, fLO = 1090 MHz, LO power = 0 dBm, ZO = 50 Ω, R

Table 1.

Parameter Conditions Min Typ Max Unit

RF INPUT INTERFACE (Pin 15, RFIN and Pin 14, RFCM)

Return Loss 10 dB
DC Bias Level Internally generated; port must be ac-coupled 2.6 V

OUTPUT INTERFACE

Output Impedance Differential impedance, f = 200 MHz 9||1 kΩ||pF
DC Bias Voltage Externally generated 4.75 VS 5.25 V
Power Range Via a 4:1 balun 13 dBm

LO INTERFACE

LO Power −10 0 +4 dBm
Return Loss 10 dB
DC Bias Voltage Internally generated; port must be ac-coupled VS − 1.6 V

POWER-DOWN INTERFACE

PWDN Threshold VS − 1.4 V
PWDN Response Time Device enabled, IF output to 90% of its final level 0.4 µs
Device disabled, supply current < 5 mA 0.01 µs

PWDN Input Bias Current Device enabled −80 µA
Device disabled 100 µA
POWER SUPPLY

Positive Supply Voltage 4.75 V

Quiescent Current

VPDC Supply current for bias cells 5 mA
VPMX, IFOP, IFOM Supply current for mixer, R

VPLO Supply current for LO limiting amplifier 35 mA
Total Quiescent Current 73 84 95 mA
Power-Down Current Device disabled 500 µA

= 2.43 kΩ 44 mA

BIAS

= 2.43 kΩ, unless otherwise noted.

BIAS

S

5.25 V

Rev. 0 | Page 3 of 20

AD8344

AC PERFORMANCE

VS = 5 V, TA = 25°C, LO power = 0 dBm, ZO = 50 Ω, R

Table 2.

Parameter Conditions Min Typ Max Unit

RF Frequency Range 400 1200 MHz
LO Frequency Range High Side LO 470 1600 MHz
IF Frequency Range 70 400 MHz
Conversion Gain fRF = 450 MHz, fLO = 550 MHz, fIF = 100 MHz 9.25 dB
f

= 890 MHz, fLO = 1090 MHz, fIF = 200 MHz 4.5 dB

RF

SSB Noise Figure fRF = 450 MHz, fLO = 550 MHz, fIF = 100 MHz 7.75 dB
f
Input Third-Order Intercept

Input Second-Order Intercept f
f

= 890 MHz, fLO = 1090 MHz, fIF = 200 MHz 10.5 dB

RF

= 450 MHz, f

f

RF1

f

= 100 MHz, each RF tone = −10 dBm

IF

= 890 MHz, f

f

RF1

= 200 MHz, each RF tone = −10 dBm

f

IF

= 450 MHz, f

RF1

= 890 MHz, f

RF1

Input 1 dB Compression Point fRF = 450 MHz, fLO = 550 MHz, fIF = 100 MHz 2.5 dBm
f

= 890 MHz, fLO = 1090 MHz, fIF = 200 MHz 8.5 dBm

RF

LO to IF Output Feedthrough LO Power = 0 dBm, fRF = 890 MHz, fLO = 1090 MHz −23 dBc
LO to RF Input Leakage LO Power = 0 dBm, fRF = 890 MHz, fLO = 1090 MHz −48 dBc
RF to IF Output Feedthrough RF Power = −10 dBm, fRF = 890 MHz, fLO = 1090 MHz −32 dBc
IF/2 Spurious RF Power = −10 dBm, fRF = 890 MHz, fLO = 1090 MHz −66 dBm

= 2.43 kΩ, unless otherwise noted.

BIAS

= 451 MHz, fLO = 550 MHz,

RF2

= 891 MHz, fLO = 1090 MHz,

RF2

= 500 MHz, fLO = 550 MHz, fIF = 100 MHz 36 dBm

RF2

= 940 MHz, fLO = 1090 MHz, fIF = 200 MHz 51 dBm

RF2

14 dBm

24 dBm

Rev. 0 | Page 4 of 20

AD8344

ABSOLUTE MAXIMUM RATINGS

Table 3.

Parameter Rating

Supply Voltage, VS 5.5 V
RF Input Level 12 dBm
LO Input Level 12 dBm
PWDN Pin VS + 0.5 V
IFOP, IFOM Bias Voltage 5.5 V
Minimum Resistor from EXRB to COMM 2.4 kΩ
Internal Power Dissipation 580 mW
θJA 77°C/W
Maximum Junction Temperature 125°C
Operating Temperature Range −40°C to +85°C
Storage Temperature Range −65°C to +150°C
Lead Temperature Range (Soldering 60 sec) 300°C

ESD 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 this product 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.

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.

Rev. 0 | Page 5 of 20

AD8344

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

COMM

RFCM

RFIN

VPMX

VPDC12PWDN11EXRB10COMM

13

14

15

16

1

2

VPLO

LOCM

3

LOIN

9

4

COMM

8

7

6

5

COMM

IFOP

IFOM

COMM

04826-0-002

Figure 2. 16-Lead LFCSP

Table 4. Pin Function Descriptions

Pin No. Mnemonic Function

1 VPLO Positive Supply Voltage for the LO Buffer: 4.75 V to 5.25 V.
2 LOCM AC Ground for Limiting LO Amplifier, AC-Coupled to Ground.
3 LOIN LO Input. Nominal input level 0 dBm, input level range −10 dBm to +4 dBm, re: 50 Ω, ac-coupled.
4, 5, 8, 9, 13 COMM Device Common (DC Ground).
6, 7 IFOM, IFOP Differential IF Outputs; Open Collectors, Each Requires DC Bias of 5.00 V (Nominal).
10 EXRB

Mixer Bias Voltage, Connect Resistor from EXRB to Ground, Typical Value of 2.43 kΩ

Sets Mixer Current to Nominal Value. Minimum resistor value from EXRB to ground = 2.4 kΩ.
11 PWDN Connect to Ground for Normal Operation. Connect pin to VS for disable mode.
12 VPDC Positive Supply Voltage for the DC Bias Cell: 4.75 V to 5.25 V.
14 RFCM AC Ground for RF Input, AC-Coupled to Ground.
15 RFIN RF Input. Must be ac-coupled.
16 VPMX Positive Supply Voltage for the Mixer: 4.75 V to 5.25 V.

Rev. 0 | Page 6 of 20