Low-Cost RF Up/Downconverter

with LNA and PA Driver

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9

_______________Detailed Description

The MAX2410 consists of five major components: a

transmit mixer, a variable-gain power-amplifier (PA)

driver, a low-noise amplifier (LNA), a receive mixer, and

power-management section.

The following sections describe each block in the

MAX2410

Functional Diagram.

Low-Noise Amplifier (LNA)

The LNA is a wideband, single-ended cascode amplifi-

er that can be used over a wide range of frequencies

(refer to the LNA Gain vs. Frequency graph in the

Typical Operating Characteristics). Its port impedances

are optimized for operation around 1.9GHz, requiring

only a 1pF shunt capacitor at the LNA input for a VSWR

of better than 2:1 and a noise figure of 2.4dB. As with

every LNA, the input match can be traded off for better

noise figure.

Typical Operating Circuit

47pF

47pF

1pF

220pF

28

27

26

25

24

23

22

1

GND

10

2

LNA

INPUT

LO

INPUT

PA

DRIVER

OUTPUT

PA

DRIVER

INPUT

TX

MIXER

RFOUTPUT

50

Ω RX

MIXER

IFOUTPUT

TX

MIXER

IFINPUT

RX

MIXER

RFINPUT

LNA

OUTPUT

3

4

5

7

8

21

20

GND

LNAOUT

GND

GND

RXMXIN

GND

IFIN

IFOUT

GND

17

18

19

LNAIN

GND

GND

LO

LO

13

18nH

16

15

GND

GND

TXMXOUT

TXEN

RXEN

GC

PADRIN

GND

MAX2410

11

6

9

220pF

1000pF

220pF

1000pF

1000pF

1000pF

220pF

3.9nH

3.9nH

68nH

82nH

220pF

220pF

PADROUT

5.6nH

68nH

220pF

1000pF

12

14

GND

GND