MGCT04 Ver la hoja de datos (PDF) - Zarlink Semiconductor Inc

Número de pieza

componentes Descripción

Fabricante

MGCT04

Transmit Circuit for TDMA/AMPS and CDMA/AMPS

Zarlink Semiconductor Inc 

Preliminary Information MGCT04

Characteristics

Value

Min. Typ. Max.

Units

Conditions

1900MHz RF output stage (PCS)

Specifications assume 50 ohm

load driven via a matching network

(Fig. 5)

RF amplifier operating frequency

range

1850

1910 MHz

Output power

+8

+18

dBm Note 1

ACPR (CDMA)

-66

-52

dBc Pout = +3dBm Vcc = 3V

ACPR (TDMA)

-45

-30

dBc Pout = +8dBm, Offset = 30kHz

Vcc = 3V

-90

-60

dBc Pout = +8dBm, Offset = 60kHz

Vcc = 3V

Receive band noise

-128

dBm/ At duplex frequency, offset 80MHz

Hz Pout = +3dBm

Receive band noise

(1930 - 1990 MHz)

-123 -121

dBm/ ftx = 1910MHz, Pout = +8dBm

Hz

Spurious Outputs

LO Leakage

-30 -20

dBc Pout = +8dBm

Image Rejection

-30 -20

dBc Pout = +8dBm

Other Spurii

-20

dBm Note 3

Notes:

Table 3 - AC Characteristics (continued)

1. V (I/Q) = 1.4V differential, VHF LO = 22mV rms, UHF LO = -15dBm, VGA = 2.6volts

2. V (I/Q) = 1.4 V dc differential, VHF LO = 22mV rms, UHF LO = -15dBm, VGA = 2.6 volts

3. Frequency range 10MHz to 10*ftx except Rx and Tx bands

Circuit Description

General

The MGCT04 circuit is designed to provide the

transmit function in dual band dual mode CDMA/

AMPS IS136/AMPS mobile phones. The circuit

contains the following blocks:

1. Quadrature modulator

2. VHF voltage controlled oscillator buffer and

divide by 8 prescaler

3. Active IF low pass filter

4. IF variable gain amplifier

5. Single sideband mixer with external UHF

oscillator inputs

6. RF variable gain amplifier

7. 900MHz and 1900MHz high power output driver

stages

8. Power and mode control logic

Quadrature Modulator

I and Q data from a baseband circuit such as the

Zarlink Semiconductor MGCM02 or MGCM03 circuit

is applied to the I and Q inputs of the quadrature

modulator to produce the intermediate frequency by

mixing with the local oscillator frequency from the

VHF VCO. The control inputs can select either a

divide by two or divide by four function between the

VHF VCO and the quadrature modulator giving a

choice of possible intermediate frequencies.

VHF Oscillator Input Oscillator Bias and

Divider

An external VHF oscillator circuit is AC coupled to

the VHF oscillator input. The oscillator drives the

quadrature modulator and an internal divide by eight

circuit to reduce the frequency of the output signal to

be sent off chip to the frequency synthesiser. This

reduces the power required in the output buffer

circuit and also allows a low frequency low power

CMOS synthesiser to be used. The divider can be

disabled if not required by connecting the output pin

(DIV OUT - pin 7) to the positive power supply. This

reduces the total supply current by typically 4mA. An

oscillator bias circuit is included on the chip so that

the external VHF oscillator transistor can be switched

off using the control inputs. The bias voltage is

5

Share Link: