WL600CGP1R Ver la hoja de datos (PDF) - Mitel Networks

Número de pieza

componentes Descripción

Fabricante

WL600CGP1R

2.4 - 2.5GHz RF and IF Circuit

Mitel Networks 

WL600C

ELECTRICAL CHARACTERISTICS (cont)

These characteristics are guaranteed over the following conditions (unless otherwise stated):

T

AMB

=

-20°C

to

+

85°C

VCC

=

2.7V

to

3.6V,

Characteristic

Value

Unit Condition

Min

Typ

Max

BUFFER AMP

Buffer amplifier gain

2

Input common mode range

1.2

Vcc-0.5

V

Output common mode

Vcc-1.5

V

Max difference between inputs

450

mV

Amp will limit outside this range

Output pull down current

350

µA

STANDBY INPUT

Chip must be in receive mode

when switching to/from standby

Logic low voltage

0

0.8

V

Circuit powered down

Logic high voltage

Vcc-0.7

Vcc

V

Circuit powered up

Input current

100

µA

Standby to receive time

µs

FUNCTIONAL DESCRIPTION

RECEIVE

The RF input stage of the WL600C receiver is a 2.5GHz

low noise amplifier (LNA). The output of the single ended LNA

is split and fed into the inputs of two mixers which form an

image rejecting down converter. An external oscillator (2.357

→ 2.457GHz)is fed through an RC phase shift network to

provide the required quadrature local oscillator signal.

The mixer outputs are fed through further phase shift

networks and are combined to form a differential 43MHz IF

signal which is used to drive the 43MHz SAW filter.

The output of the SAW filter is fed into a differential limiting

strip which provides the IF gain. The strip has a series of

detectors whose output provides an analog voltage indicating

receive signal strength (RSSI). Alternatively, for basic

applications a comparator connected to the RSSI detectors

can be used. When the RSSI signal is greater than a value set

by the CCA_THRESHOLD input the clear channel

assessment (CCAB) output goes high.

A conventional quadrature demodulator (with external

tuned circuit to supply the quadrature drive) provides the

analogue data stream which is then AC coupled to a data slice

comparator. A clamp circuit is connected between the

comparator inputs to provide DC restoration of the AC coupled

signal. The comparator output then goes to the data and clock

recovery circuits on a CMOS integrated circuit (such as the

WL102).

TRANSMIT

The local oscillator signal is also used in transmit at a

higher frequency (2.4 →2.5GHz) and is buffered and amplified

on the WL600C. This provides the drive to the transmit power

amplifier (also off chip).

A ramp circuit is included to control the drive level to the

power amplifier in a controlled manner. This is done at the start

and end of a transmit sequence and should be used to prevent

the generation of spectral “splash”. A single external capaci-

tor controls the rate of increase and decrease of the power

drive level.

6

Share Link: