Datasheet

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General Description

The MAX2371/MAX2373 wideband low-noise amplifier

(LNA) ICs are designed for direct conversion receiver

(DCR) or very low intermediate frequency (VLIF) receiver

applications. They contain single-channel, single-ended

LNAs with switchable attenuator and automatic gain con-

trol (AGC) intended as a low-noise gain stage. These

devices provide high gain-control range (typically 60dB)

at radio frequency (RF) with excellent noise and reverse

isolation characteristics.

The MAX2371/MAX2373 can work over the frequency

range from 100MHz to 1GHz. In practice, only a narrow

band is needed in each application, so different matching

circuits can be applied. The devices are dynamically con-

figured through the digital/analog control pins to select

either maximum gain and low noise figure or power-saving

mode. In addition, the MAX2371/MAX2373 feature

high/low-current modes, high/low attenuation modes, lin-

early controlled gain states, and shutdown mode.

Applications

Direct Conversion Receiver (DCR)

Very Low IF Receiver

Features

♦ Low Noise Figure (1.8dB typical)

♦ High Small-Signal Gain (15dB Nominal)

♦ Wide Frequency Range of Operation

(100MHz to 1GHz)

♦ 20dB Step Attenuator

♦ 45dB AGC Range Excluding Step Attenuator

♦ 2.65V to 3.3V Single-Supply Operation

♦ Shutdown Mode

♦ 3.5mA Supply Current, Adjustable Down to 2.5mA

♦ 40dB Reverse Isolation

MAX2371/MAX2373

LNAs with Step Attenuator and VGA

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-2301; Rev 1; 10/06

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.

EVALUATION KIT

AVAILABLE

PART

TEMP RANGE

PIN-

PACKAGE

PKG

CODE

MAX2371EGC

-40°C to +85°C

12 QFN-EP*

G1233-1

MAX2371ETC

-40°C to +85°C 12 TQFN-EP*

T1233-3

MAX2371ETC+

-40°C to +85°C 12 TQFN-EP*

T1233+3

MAX2373EGC

-40°C to +85°C

12 QFN-EP*

G1233-1

MAX2373ETC

-40°C to +85°C 12 TQFN-EP*

T1233-3

MAX2373ETC+

-40°C to +85°C 12 TQFN-EP*

T1233+3

TOP VIEW

GND

RF_V

RSET

AGC

LNA_I

2LNA_E

7RX_EN

AGC_BYP

LNA_V

LNA_OUT

MAX2371

MAX2373

LNA_IN

RF_ATTN

QFN/TQFN

Pin Configuration

AGC

RF_V

GND

LNA_OUT

LNA_IN

AGC_BYP

EXPONENTIAL

CONVERTER

AGC

AMP

LNA

RF_ATTN

ATTENUATOR

LNA_V

LNA_I

RX_EN

LNA_E

RSET

MAX2371

MAX2373

Functional Diagram

*EP = Exposed pad.

+Denotes lead-free package.

Summary of content (10 pages)

PAGE 1
9-2301; Rev 1; 10/06 KIT ATION EVALU E L B AVAILA LNAs with Step Attenuator and VGA The MAX2371/MAX2373 wideband low-noise amplifier (LNA) ICs are designed for direct conversion receiver (DCR) or very low intermediate frequency (VLIF) receiver applications. They contain single-channel, single-ended LNAs with switchable attenuator and automatic gain control (AGC) intended as a low-noise gain stage.
PAGE 2
MAX2371/MAX2373 LNAs with Step Attenuator and VGA ABSOLUTE MAXIMUM RATINGS VCC to GND ...........................................................-0.3V to +3.6V All Pins Excluding Grounds to Pin GND.....-0.3V to (VCC + 0.3V) LNA Input Power (RX_EN = low) ........................................5dBm Continuous Power Dissipation (TA = +70°C) 12-Pin QFN (derate 11.9mW/°C above +70°C) ...........952mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ...................
PAGE 3
LNAs with Step Attenuator and VGA (MAX2371/MAX2373 EV Kits, VCC = 2.65V to 3.3V, RX_EN = high, RSET = 1.1kΩ, TA = -40°C to +85°C. Typical values are at VCC = 2.775V; for MAX2371 fRF = 150MHz, for MAX2373 fRF = 850MHz to 940MHz; TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS LNA_I = high, TA = +25°C, VCC = 2.775V, RF_ATTN = low SSB Noise Figure vs. AGC LNA_I = low, TA = +25°C, VCC = 2.775V, RF_ATTN = low Input 1dB Compression Point RF_ATTN = low, VAGC < 1.8V RF_ATTN = high, VAGC < 1.
PAGE 4
Typical Operating Characteristics (MAX2371/MAX2373 EV Kits, VCC = 2.775V, RX_EN = high, RSET = 1.1kΩ, LNA_I = high, TA = +25°C. For MAX2371, fRF = 150MHz; for MAX2373, fRF = 900MHz, unless otherwise noted.) MAX2371 GAIN vs. VAGC RF_ATTN = LOW 10 TA = -40°C 0 15 -10 10 -20 TA = +85°C -30 0 RF_ATTN = HIGH -5 TA = -40°C -50 -10 RF_ATTN = HIGH RF_ATTN = LOW -60 -10 140 150 160 170 -15 1.2 180 1.6 2.0 P1dB vs. VAGC TA = +85°C -10.0 25 -15.0 20 15 10 5 -25.0 0 1.7 2.2 2.
PAGE 5
LNAs with Step Attenuator and VGA MAX2373 RF_ATTN = LOW 10 RF_ATTN = HIGH 15 10 TA = +85°C 0 -10 -20 TA = -40°C TA = +25°C -30 -5 -10 RF_ATTN = LOW -15 -50 860 880 900 920 940 1.2 1.6 2.0 FREQUENCY (MHz) P1dB vs. VAGC 1.5 TA = 85°C -10.0 -15.0 RF_ATTN = LOW 15 RF_ATTN = LOW 10 1.8 S11 -5 -10 -15 S22 -20 -25 S11 RF_ATTN = LOW -30 RF_ATTN = HIGH -35 -40 5 -20.0 1.7 0 MAX2371 toc12 RF_ATTN = HIGH 20 1.6 S11, S22, S12 vs.
PAGE 6
MAX2371/MAX2373 LNAs with Step Attenuator and VGA Table 1. MAX2371 S-Parameters (VCC = 2.775V, RX_EN = high, LNA_I = high, RF_ATTN = low, PIN = -30dBm, TA = +25°C.) LNA (S11) FREQUENCY (MHz) MAGNITUDE PHASE 6 LNA (S21) LNA (S12) LNA (S22) MAGNITUDE PHASE MAGNITUDE PHASE MAGNITUDE PHASE 10 0.943409 -4.8477 5.980672 171.1200 0.002136 -102.490 0.998803 -1.1632 100 0.746965 -29.9420 2.959750 102.1900 0.002021 61.149 0.994752 -4.4481 150 0.728794 -35.6990 2.347308 89.6950 0.
PAGE 7
LNAs with Step Attenuator and VGA MAX2371/MAX2373 Table 2. MAX2373 S-Parameters (VCC = 2.775V, RX_EN = high, LNA_I = high, RF_ATTN = low, PIN = -30dBm, TA = +25°C.) LNA (S11) FREQUENCY (MHz) MAGNITUDE PHASE LNA (S21) LNA (S12) LNA (S22) MAGNITUDE PHASE MAGNITUDE PHASE MAGNITUDE PHASE -0.8171 7.273610 -178.830 0.002162 -89.276 1.000092 -0.8184 10 0.952248 100 0.933405 -9.1461 7.077013 163.940 0.001346 78.684 0.993482 -2.3140 200 0.884179 -16.6570 6.529802 150.770 0.
PAGE 8
MAX2371/MAX2373 LNAs with Step Attenuator and VGA Table 4. MAX2373 Typical Noise Parameters (VCC = 2.775V, RX_EN = high, LNA_I = high, RF_ATTN = low, PIN = -30dBm, TA = +25°C, data from design simulation.) FREQUENCY (MHz) NFMIN (dB) ⎜ΓOPT⎟ ∠ ΓOPT RN (Ω) 850 870 890 910 930 950 1.06 1.08 1.10 1.11 1.13 1.15 0.35 0.35 0.34 0.34 0.33 0.33 60.5 61.8 63.3 64.7 66.2 67.7 10.02 9.98 9.94 9.90 9.86 9.82 Pin Description PIN NAME 1 2 3 LNA_IN LNA_E RX_EN FUNCTION 4 RF_ATTN RF Input.
PAGE 9
LNAs with Step Attenuator and VGA capacitor means a good IP3 and slow startup. The maximum startup time is determined by the equation below: Applications Information IP3 will improve with the separation of the interfering tones, so a wider channel system can use a smaller DCblocking capacitor and achieve a better IP3. The customer also can change the emitter inductor at LNA_E to get the desired linearity and gain. Changing this inductor value requires a change to the input match.
PAGE 10
MAX2371/MAX2373 LNAs with Step Attenuator and VGA Typical Operating Circuits 1.1kΩ PRECISION 2.775 VDC GND RF_VCC RSET AGC_BYP RF INPUT MATCH MAX2371 MAX2373 LNA_IN LNA_E RF ATTENUATOR LNA_VCC AGC AMP LNA LNA_OUT RX_EN EXPONENTIAL CONVERTER RF_ATTN AGC LNA_I Chip Information Impedance-Matching Network Layout The input- and output-matching networks are sensitive to layout-related parasitic inductions.