MAX2371 Ver la hoja de datos (PDF) - Maxim Integrated

Número de pieza

componentes Descripción

Fabricante

MAX2371

LNAs with Step Attenuator and VGA

Maxim Integrated 

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)

850

870

890

910

930

950

NFMIN (dB)

1.06

1.08

1.10

1.11

1.13

1.15

⎜ΓOPT⎟

0.35

0.35

0.34

0.34

0.33

0.33

∠ ΓOPT

60.5

61.8

63.3

64.7

66.2

67.7

RN (Ω)

10.02

9.98

9.94

9.90

9.86

9.82

Pin Description

PIN

NAME

FUNCTION

1

LNA_IN RF Input. Requires DC-blocking capacitor and external matching network.

2

LNA_E LNA Emitter. Connect to GND with an inductor. See inductor value in Table 5.

3

RX_EN LNA Control. Set RX_EN high to enable LNA; set RX_EN low to disable LNA.

4

RF_ATTN Attenuator Control. Set RF_ATTN high for low-gain mode; set RF_ATTN low for high-gain mode.

5

AGC

AGC Input Voltage. Set AGC to VCC/2 for maximum gain. Set AGC to VCC - 200mV for minimum gain. If

left unconnected, the LNA will operate at maximum gain and optimum noise figure.

6

LNA_I

LNA Nominal Bias-Current Setting. Set LNA_I high for high-current mode. Set LNA_I low for low-current

mode. If left unconnected, the default state of the LNA is high-current mode.

7

LNA_OUT RF Output Pin. Requires a pullup inductor to LNA_VCC and external matching network.

8

LNA_VCC Supply Voltage for the AGC Amplifier

9

AGC_BYP

AGC Bypass. Connect a capacitor to ground. The value of the capacitor is a compromise of AGC

response time and blocker frequency offset.

10

RSET

External pin for precision resistor to ground to set reference bias current for IC; typical bias current is

50µA to 100µA.

11

RF_VCC

Supply Voltage for the LNA. Bypass with a capacitor to GND as close to the pin as possible. Do NOT

connect any tuned circuits to this supply pin.

12

GND

Ground

Exposed Internally connected to GND. Connect to a large ground plane to maximize thermal performance.

EP

Pad

Do not use as the sole ground connection point.

Table 5. Inductor Selection

BAND

150MHz (VHF)

450MHz (UHF)

450MHz (UHF)

800MHz

1GHz

L SERIES VALUE

(nH)

33

10

2.7

2.5

1.8

LNA TYPE

Low Band

Low Band

High Band

High Band

High Band

Detailed Description

The MAX2371/MAX2373 are single-channel, single-

ended, low-noise amplifiers with two gain modes and

continuous automatic gain control (AGC) in both

modes. The devices are intended as low-noise gain

stages for direct conversion receivers (DCR) or very

low IF (VLIF) receivers. These devices provide high

gain-control dynamic range (typ 60dB) at RF with

excellent noise and reverse isolation characteristics.

Vary the resistor at pin RSET and the inductor at LNA_E

to meet a wide range of gain and linearity require-

ments. The ICs can be dynamically configured through

pins LNA_I and RF_ATTN. When LNA_I is connected to

VCC, the LNA is in high-current mode, nominally config-

ured for maximum gain and low noise figure of the

amplifier. If the LNA_I pin is grounded, the current of

the LNA is reduced, and the associated gain, input IP3,

and noise figure are degraded. The devices have two

gain modes configured by the RF_ATTN pin. Set

RF_ATTN high for low-gain mode; set RF_ATTN low for

high-gain mode. The gain step between these two gain

modes typically is 20dB.

8 _______________________________________________________________________________________

Share Link: