Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsLinear ICsMAX2645EUB+

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 resis-

tor, that allows the user to meet minimum linearity require-

ments 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 pro-

vides 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 high-

gain 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 1; 8/03

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*

*EP = exposed paddle.

APPLICATION

CIRCUIT

LNA, LOW NF 14.4/-9.7 2.3/15.5

+4/+13

+10/+15.5

+11.8/+16.2

2.6/16

14.9/-10.7

15.2/-9.7

LNA, HIGH IP3

PA PREDRIVER

GAIN

(dB)

IIP3

(dBm)

MAX2645

BIAS AND POWER

MANAGEMENT

RFIN

INPUT

3.5GHz

HIGH

GAIN

LOW

GAIN

GND

GAIN STEP

SHUTDOWN

LOGIC

INPUTS

BIAS

RADIAL STUB

OUTPUT

LINE

Typical Operating Circuit

EVALUATION KIT

AVAILABLE

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Summary of content (12 pages)

PAGE 1
9-1759; Rev 1; 8/03 KIT ATION EVALU E L B A IL AVA 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver Applications 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.
PAGE 2
MAX2645 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver ABSOLUTE MAXIMUM RATINGS VCC to GND ...........................................................-0.3V to +6.0V GAIN, SHDN, RFOUT to GND .....................0.3V to (VCC + 0.3V) RFIN Input Power (50Ω source)........................................16dBm Minimum RBIAS ....................................................................10kΩ Continuous Power Dissipation (TA = +70°C) 10-Pin µMAX-EP (derate 10.3mW/°C above TA = +70°C) ................
PAGE 3
.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver (MAX2645 EV kit, V CC = GAIN = SHDN = +3.3V,R BIAS = 20kΩ ±1%, P RFIN = -20dBm, f RFIN = 3550MHz, Z o = 50Ω, TA = +25°C, unless otherwise noted.) PARAMETER Frequency Range Gain (Note 3) Gain Variation over Temperature CONDITIONS MIN TYP MAX UNITS 3800 MHz (Note 2) 3400 GAIN = VCC 12.9 14.4 15.4 GAIN = GND -11.8 -9.7 -8.0 ±0.3 ±0.7 TA = -40°C to +85°C, GAIN = VCC or GND (Note 4) ±24.
PAGE 4
AC ELECTRICAL SPECIFICATIONS—PA Predriver Application Circuit (MAX2645 EV kit, V CC = GAIN = SHDN = +3.3V,R BIAS = 20kΩ ±1%, P RFIN = -20dBm, f RFIN = 3550MHz, Z o = 50Ω, TA = +25°C, unless otherwise noted.) PARAMETER CONDITIONS Frequency Range MIN (Note 2) Gain Gain Variation over Temperature Input Third-Order Intercept Input 1dB Compression Point Noise Figure Reverse Isolation TYP 3400 MAX UNITS 3800 MHz GAIN = VCC 15.2 GAIN = GND -9.7 TA = -40°C to +85°C, GAIN = VCC or GND ±0.3 dB 24.
PAGE 5
3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver GAIN vs. FREQUENCY (LOW-GAIN MODE) 15 -6 TA = +85°C 9 8 -14 3.5 -15 3.6 3.7 TA = +85°C TA = +85°C 13.8 13.6 13.2 LOW-NOISE FIGURE CIRCUIT 3.5 3.6 13.0 3.7 3.8 LOW-NOISE FIGURE CIRCUIT 3.0 4.0 3.5 4.5 5.0 FREQUENCY (GHz) SUPPLY VOLTAGE (V) GAIN vs. SUPPLY VOLTAGE (LOW-GAIN MODE) GAIN STEP vs. SUPPLY VOLTAGE GAIN vs. RBIAS (HIGH-GAIN MODE) GAIN STEP (dB) -8.5 TA = +25°C -9.0 -9.5 TA = +85°C -10.0 14.8 25.0 TA = -40°C 5.
PAGE 6
Typical Operating Characteristics (continued) (MAX2645 EV kit, VCC = +3.3V, RBIAS = 20kΩ, fRFIN = 3550MHz, TA = +25°C, unless otherwise noted.) INPUT IP3 vs. SUPPLY VOLTAGE (LOW-GAIN MODE) TA = -40°C 5.5 TA = +85°C 5.0 15.0 4.0 3.5 TA = +25°C 3.0 2.5 17.5 20.0 22.5 25.0 3.0 RBIAS (kΩ) INPUT IP3 vs. RBIAS (HIGH-GAIN MODE) 3.5 4.5 5.0 INPUT IP3 (dBm) 5 3 VCC = 3.3V 3.0 -3.5 MAX2645-17 13.5 13.0 11.5 17.5 20.0 22.5 25.0 15.0 17.5 20.
PAGE 7
3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver REVERSE ISOLATION (dB) 3.5 3.0 HIGH GAIN 2.5 15.5 -15 LOW GAIN -20 HIGH GAIN 3.5 3.6 3.7 3.8 3.5 3.6 3.7 FREQUENCY (GHz) -11.0 HIGH-INPUT IP3 CIRCUIT 4.5 -13.0 19 3.0 LOW GAIN 2.5 2.0 -14.0 HIGH GAIN HIGH-INPUT IP3 CIRCUIT 15 14 TA = +25°C 3.5 3.6 3.7 10 3.4 3.8 3.5 3.6 3.7 3.8 PA PREDRIVER CIRCUIT 3.4 3.5 3.6 3.7 FREQUENCY (GHz) FREQUENCY (GHz) GAIN vs. FREQUENCY (LOW-GAIN MODE) GAIN vs.
PAGE 8
Typical Operating Characteristics (continued) (MAX2645 EV kit, VCC = +3.3V, RBIAS = 20kΩ, fRFIN = 3550MHz, TA = +25°C, unless otherwise noted.) OUTPUT POWER vs. INPUT POWER (LOW-GAIN MODE) 12 TA = +25°C 10 TA = -40°C INPUT VSWR vs. FREQUENCY PA PREDRIVER CIRCUIT 3.5 4.0 -5 SUPPLY VOLTAGE (V) 5.0 5.5 PA PREDRIVER CIRCUIT VCC = 5V 3.5 TA = +25°C -10 3.0 LOW GAIN 2.5 -15 -25 4.5 4.5 TA = -40°C 2.0 HIGH GAIN -20 3.0 5.0 4.
PAGE 9
3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver Gain Step Control The MAX2645 features a logic-level gain step control input (GAIN) that places the device in high-gain or lowgain mode. A logic-level high places the device in highgain mode, where the gain is 14.5dB. A logic-level low places the device in low-gain/high-linearity mode, where the gain is reduced to 10dB and the input IP3 performance is increased.
PAGE 10
MAX2645 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver Table 2. MAX2645 Noise Parameters |Γopt| Γopt ANGLE RN (Ω) FREQUENCY (MHz) FMIN (dB) 3400 2.098 0.237 144.1 31.1 3450 2.122 0.235 146.1 31.5 3500 2.148 0.235 148.2 32.0 3550 2.173 0.234 150.3 32.5 3600 2.198 0.233 152.4 32.9 3650 2.225 0.232 154.5 33.5 3700 2.251 0.231 156.5 33.9 3750 2.279 0.230 158.6 34.5 3800 2.306 0.229 160.7 35.0 3400 2.103 0.210 146.3 31.1 3450 2.127 0.209 148.
PAGE 11
3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver VCC GND VCC 0.1µF 47pF 2 C1 RF INPUT 3.4GHz to 3.8GHz MAX2645 1 GND GAIN 9 HIGH GAIN LOW GAIN 8 ON OFF MAX2645 3 RFIN SHDN GND GND Z1 4 7 RADIAL STUB * 40° 5 220pF BIAS RFOUT TLINE LEQUIV = 1.5nH 8 294 mil s VCC 1000pF RF OUTPUT RBIAS 0.75pF APPLICATION CIRCUIT LNA, LOW NF LNA, HIGH INPUT IP3 PA PREDRIVER C1 Z1 1.5pF 1000pF 0.01µF 1.8nH 0.75pF 0.75pF RBIAS (kΩ) VCC (V) 20 3.3 20 15 3.3 5.
PAGE 12
Pin Configuration Chip Information TRANSISTOR COUNT: 271 TOP VIEW GND 1 10 VCC GND 2 RFIN 3 9 GAIN 8 SHDN GND 4 7 GND BIAS 5 6 RFOUT MAX2645 µMAX-EP Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) e 10LUMAX.EPS MAX2645 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver 4X S 10 10 INCHES H ÿ 0.50±0.1 0.6±0.1 1 1 0.6±0.