Rainbow Electronics MAX2645 User Manual

General Description

The MAX2645 is a versatile, high-linearity, low-noise amplifier designed for 3.4GHz to 3.8GHz wireless local loop (WLL), wireless broadband access, and digital microwave radio applications. The device features an externally adjustable bias control, set with a single resistor, that allows the user to meet minimum linearity requirements while minimizing current consumption. The amplifier’s high-gain, low-noise performance and adjustable input third-order intercept (IP3) allow it to be used as a low-noise amplifier (LNA) in the receive path, a PA predriver in the transmit path, or as an LO buffer.

The MAX2645 features a logic-level gain control that provides a 25dB step reduction in gain, which improves IP3 performance for operation during high input signal level conditions. Supply current is reduced from 9mA in highgain mode to 3mA in low-gain mode. The device also includes a logic-controlled shutdown mode, which reduces supply current to 0.1µA. The MAX2645 operates from a +3V to +5.5V supply and is offered in the miniature 10-pin µMAX package (5mm ✕3mm) with an exposed paddle. Its performance has been optimized for use with the MAX2683/MAX2684 3.5GHz SiGe mixers to provide a complete high-performance, front-end solution for 3.5GHz applications.

Applications

Wireless Local Loop

Wireless Broadband Access

Digital Microwave Radios

Features

♦ 3.4GHz to 3.8GHz Frequency Range

♦ LNA Performance (High/Low-Gain Modes)

Gain: +14.4dB/-9.7dB NF: 2.3dB/15.5dB Input IP3: +4dBm/+13dBm Supply Current: 9.2mA/2.7mA

♦ Highly Versatile Application

Receive Path 1st and 2nd Stage LNA Transmit PA Predriver LO Buffer

♦ Adjustable IP3 and Supply Current

♦ 0.1µA Supply Current in Shutdown Mode

♦ +3.0V to +5.5V Single-Supply Operation

♦ 10-Pin µMAX-EP Package (5.0mm x 3.0mm)

MAX2645

________________________________________________________________ Maxim Integrated Products 1

19-1759; Rev 0; 7/00

For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800. For small orders, phone 1-800-835-8769.

3.4GHz to 3.8GHz SiGe

Low-Noise Amplifier/PA Predriver

Ordering Information

Pin Configuration appears at end of data sheet.

PART TEMP. RANGE

PIN-PACKAGE

MAX2645EUB -40°C to +85°C 10 µMAX-EP*

*Exposed paddle

Typical Operating Circuit

EVALUATION KIT MANUAL

FOLLOWS DATA SHEET

GAIN STEP

LOGIC INPUTS

INPUT

3.5GHz

SHUTDOWN

BIAS

RFIN

GND

BIAS AND POWER

HIGH GAIN

LOW GAIN

MANAGEMENT

MAX2645

RADIAL STUB

APPLICATION

CIRCUIT

LNA, LOW NF 14.4/-9.7 2.3/15.5 LNA, HIGH IP3 PA PREDRIVER

LINE

RF OUTPUT

GAIN

(dB)

14.9/-10.7

15.2/-9.7

(dB)

2.6/16

IIP3

(dBm)

+4/+13

+10/+15.5

+11.8/+16.2

MAX2645

3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

VCCto GND...........................................................-0.3V to +6.0V

GAIN, SHDN, RFOUT to GND .....................0.3V to (V

+ 0.3V)

RFIN Input Power (50Ω source)........................................16dBm

Minimum R

BIAS

....................................................................10kΩ

Continuous Power Dissipation (T

= +70°C) 10-Pin µMAX-EP (derate 10.3mW/°C above T

= +70°C) ....................825mW

Operating Temperature Range ...........................-40°C to +85°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

DC ELECTRICAL CHARACTERISTICS

(VCC= +3.0V to +5.5V, GAIN = SHDN = VCC, R

BIAS

= 20kΩ, no RF signals applied, TA= -40°C to +85°C. Typical values are at V

= +3.3V, TA= +25°C, unless otherwise indicated.)

PARAMETER CONDITIONS

MIN

TYP

MAX

UNITS

Supply Voltage 3.0

GAIN = V

9.2

BIAS

= 20kΩ,

= +25°C

GAIN = GND 2.7

GAIN = V

BIAS

= 20kΩ,

= -40°C to +85°C

GAIN = GND

GAIN = V

Operating Supply Current

BIAS

= 15kΩ,

= +25°C

GAIN = GND 3.6

Shutdown Supply Current SHDN = GND 0.1 2 µA Input Logic Voltage High GAIN, SHDN 2.0 V Input Logic Voltage Low GAIN, SHDN

GAIN = SHDN = V

Input Logic Bias Current

GAIN = SHDN = GND -10

µA

5.5

10.9

3.9

11.6

4.0

0.6

MAX2645

3.4GHz to 3.8GHz SiGe

Low-Noise Amplifier/PA Predriver

_______________________________________________________________________________________ 3

AC ELECTRICAL CHARACTERISTICS—LNA (Low-Noise Figure Application Circuit)

(MAX2645 EV kit, VCC= GAIN = SHDN = +3.3V,R

BIAS

= 20kΩ ±1%, P

RFIN

= -20dBm, f

RFIN

= 3550MHz, Zo= 50Ω,

= +25°C, unless otherwise noted.)

PARAMETER CONDITIONS

Frequency Range (Note 1)

GAIN = V

Gain (Note 2)

GAIN = GND

Gain Variation over Temperature TA = -40°C to +85°C, GAIN = VCC or GND (Note 3)

Gain Step

GAIN = VCC (Note 4) +4

Input Third-Order Intercept

GAIN = GND (Note 5)

GAIN = V

-5

Input 1dB Compression Point

GAIN = GND 0

GAIN = VCC (Notes 3, 6) 2.3 3.0

Noise Figure

GAIN = GND

GAIN = V

Reverse Isolation

GAIN = GND 19

Gain Step Transition Time (Note 7) 1 µs

Turn-On/Turn-Off Time (Note 8) 0.5 µs

AC ELECTRICAL SPECIFICATIONS—LNA (High-Input IP3 Application Circuit)

(MAX2645 EV kit, VCC= GAIN = SHDN = +3.3V,R

BIAS

= 20kΩ ±1%, P

RFIN

= -20dBm, f

RFIN

= 3550MHz, Zo= 50Ω,

= +25°C, unless otherwise noted.)

PARAMETER CONDITIONS

UNITS

Frequency Range (Note 1)

MHz

GAIN = V

Gain

GAIN = GND

Gain Variation over Temperature TA = -40°C to +85°C, GAIN = VCC or GND

Gain Step

GAIN = VCC (Note 5)

Input Third-Order Intercept

GAIN = GND (Note 6)

dBm

GAIN = V

-4

Input 1dB Compression Point

GAIN = GND 0

dBm

GAIN = V

2.6

Noise Figure

GAIN = GND 16

GAIN = V

Reverse Isolation

GAIN = GND 19

MIN TYP MAX UNITS

3400 3800 MHz

12.9 14.4 15.4

-11.8 -9.7 -8.0

±0.3 ±0.7

±24.1

+13

15.5

dBm

MIN TYP MAX

3400 3800

14.9

-10.7

±0.3

25.6

+10.0 +15.5

3.0 3.5 4.0 4.5 5.0 5.5

SUPPLY CURRENT vs. SUPPLY VOLTAGE

(HIGH-GAIN MODE)

MAX2645-01

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (mA)

TA = +25°C

TA = +85°C

TA = -40°C

TA = +25°C

TA = +85°C

BIAS

= 20kΩ

TA = -40°C

BIAS

= 15kΩ

2.0

3.0

2.5

4.0

3.5

4.5

5.0

3.0 4.03.5 4.5 5.0 5.5

SUPPLY CURRENT vs. SUPPLY VOLTAGE

(LOW-GAIN MODE)

MAX2645-02

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (mA)

TA = +85°C

TA = +25°C

TA = +85°C

TA = -40°C

BIAS

= 15kΩ

BIAS

= 20kΩ

15 20 25

SUPPLY CURRENT vs. R

BIAS

MAX2645-03

BIAS

(kΩ)

SUPPLY CURRENT (mA)

HIGH GAIN

LOW GAIN

VCC = 3.3V

VCC = 5V

VCC = 3.3V

Typical Operating Characteristics

(MAX2645 EV kit, VCC= +3.3V, R

BIAS

= 20kΩ, f

RFIN

= 3550MHz, TA = +25°C, unless otherwise noted.)

MAX2645

3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver

4 _______________________________________________________________________________________

AC ELECTRICAL SPECIFICATIONS—PA Predriver Application Circuit

(MAX2645 EV kit, VCC= GAIN = SHDN = +3.3V,R

BIAS

= 20kΩ ±1%, P

RFIN

= -20dBm, f

RFIN

= 3550MHz, Zo= 50Ω,

= +25°C, unless otherwise noted.)

PARAMETER CONDITIONS

UNITS

Frequency Range (Note 1)

MHz

GAIN = V

Gain

GAIN = GND

Gain Variation over Temperature TA = -40°C to +85°C, GAIN = VCC or GND

Gain Step

GAIN = VCC (Note 5)

Input Third-Order Intercept

GAIN = GND (Note 6)

dBm

GAIN = V

Input 1dB Compression Point

GAIN = GND 0

dBm

GAIN = V

2.6

Noise Figure

GAIN = GND 16

GAIN = V

Reverse Isolation

GAIN = GND 19

Note 1: This is the recommended operating frequency range. Operation outside this frequency range is possible but has not been

characterized. The device is characterized and tested at 3550MHz. For optimum performance at a given frequency, the output matching network must be properly designed. See Applications Information section.

Note 2: Specifications are corrected for board losses (0.25dB at input, 0.25dB at output). Note 3: Guaranteed by design and characterization. Note 4: Input IP3 measured with two tones, f

= 3550MHz and f2= 3551MHz, at -20dBm per tone.

Note 5: Input IP3 measured with two tones, f

= 3550MHz and f2= 3551MHz, at -12dBm per tone.

Note 6: Specifications are corrected for board losses (0.25dB at input). Note 7: Time from when GAIN changes state to when output power reaches 1dB of its final value. Note 8: Time from when SHDN changes state to when output power reaches 1dB of its final value.

MIN TYP MAX

3400 3800

15.2

-9.7

±0.3

24.9

+11.8

+16.2

-1.8

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