GaAs MMIC Low Noise Amplifier SOIC-8 Platform

Rev. V3

Application Note

M540

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2

Visit www.macomtech.com for additional data sheets and product information.

M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make

changes to the product(s) or information contained herein without notice.

The present MMIC LNA product family consists of the

following products:

Part #

Intended

Features

Market

AM50-0002

GPS, PDC

Frequency:

1.575 GHz

Gain:

27 dB

Noise Figure:

1.15 dB

Bias: 3-5V @ 20 mA

MAAM12021

GPS, PDC

Frequency:

1.5-1.6 GHz

Gain:

21 dB

Noise Figure:

1.55 dB

Bias: 3-5V @ 8 mA

MAAM12022

GPS, PDC

Frequency:

1.5-1.6 GHz

Gain:

14 dB

Noise Figure:

1.85 dB

Bias: 3-5 V @ 5 mA

MAAM12031

PCN, PCS,

Frequency:

1.7-2.0 GHz

PHS, DECT

Gain:

20 dB

DCS-1800 Noise Figure:

1.65 dB

Bias: 3-5 V @ 8 mA

MAAM12032

PCN, PCS

Frequency:

1.7-2.0 GHz

PHS, DECT

Gain:

13 dB

DCS-1800 Noise Figure:

1.8 dB

Bias: 3-5 V @ 5 mA

MAAM22010

ISM, WLAN

Frequency:

2.4-2.5 GHz

Gain:

14 dB

Noise Figure:

1.9 dB

Bias: 3-5 V @ 5 mA

AM50-0001

GSM,

Frequency:

0.8-1.0 GHz

AMPS,

Gain:

14 dB

TACS

Noise Figure:

1.5 dB

Output IP3:

+30 dBm

Bias: 5 V @ 50 mA

All these products are offered in industry standard

(JEDEC) SOIC-8 narrow body plastic packages.

MMIC Electrical Design Considerations

The key to any IC design is a well modeled stable

process to predict circuit performance. The MMIC LNAs

are based on M/A-COM’s mature 0.5-micron (μm) low

noise GaAs MESFET process. The active layer of the

GaAs substrate is formed using ion-implantation for high

throughput and low cost.

A “buried-p” doping layer

combined

with

0.5-μm

T-gates

results

in

high

respectively. Every wafer is characterized for DC and

RF performance. Process control parameters, as well as

MIM capacitance, thin film resistance, and FET RF

equivalent circuit, are stored in a database. From this

database, a statistical circuit model is derived for

designers to use in optimizing their design for maximum

yield.

Another critical aspect in the success of this MMIC LNA

product family is the ability to model all aspects of the

product

performance

in

the

plastic

packaging

environment.

Quantifying the impact of the plastic

encapsulant on the electrical performance of the die for

both the FETs and spiral inductors was a significant

challenge. No less a challenge was the electrical circuit

modeling of the SOIC-8 package itself in terms of the self

and mutual inductances of the leads, bond wires, and

split paddle lead frame.

This extensive modeling of the MMIC elements (FETs,

MIM capacitors, thin film resistors, and spiral inductors),

bond wires, and plastic package effects has allowed M/

A-COM to predict with high confidence the performance

of these and other designs. Utilizing these models with

our statistical design methodology has allowed us to

achieve high performance, unconditionally stable LNAs

with high yield and, therefore, low cost. Figures 1 and 2

show the statistical distribution of the gain and noise

figure, respectively, for the MAAM12021.

In this product platform there are essentially two circuit

design types, a low gain (LG) and a high gain (HG). The

LG design (MAAM12022, MAAM12032, MAAM22010,

and AM50-0001), shown in Figure 3, employs a single

stage cascade configuration with series feedback to

simultaneously achieve impedance match and minimum

noise figure.

The HG design (MAAM12021 and

MAAM12031), shown in Figure 4, uses two cascaded

common source stages biased in series to achieve the

high gain at low current consumption, and also employs

series feedback to simultaneously achieve impedance

match and minimum noise figure.

MMIC LNA Product Design and

Performance Features

The GaAs MMIC LNAs discussed in this application note

were carefully designed, considering not only the electri-

cal specifications but also ease and cost of manufactur-

ing as well as quality and reliability. The following three

subsections discuss in detail the inner workings of these

MMIC LNAs in terms of circuit design, manufacturing,

and quality.