SP5730 데이터 시트보기 (PDF) - Mitel Networks

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SP5730

1.3GHz Low Phase Noise Frequency Synthesiser

Mitel Networks 

Preliminary Information

Absolute Maximum Ratings

All voltages are referred to Vee at 0V

Characteristic

Min

Supply voltage, Vcc

-0.3

RF input voltage

All I/O port DC offsets

-0.3

SDA and SCL DC offset

-0.3

Storage temperature

-55

Junction temperature

QP16 thermal resistance,

chip to ambient

chip to case

Power consumption at

Vcc = 5.5V

ESD protection

2

Max

7

2.5

Vcc+0.3

6V

+150

150

80

20

83

Units

V

Vpp

V

oV

oC

C

°C/W

°C/W

mW

kV

SP5730

Conditions

Transient

Differential

All ports off

mil std 883 latest revision method 3015

class 1

Functional Description

The SP5730 contains all the elements necessary, with

the exception of a frequency reference, loop filter and

external high voltage transistor, to control a varicap

tuned local oscillator, so forming a complete PLL

frequency synthesised source. The device allows for

operation with a high comparison frequency and is

fabricated in high speed logic, which enables the

generation of a loop with good phase noise performance.

It can also be operated with comparison frequencies

appropriate for frequency offsets as required in digital

terrestrial (DTT) receivers The block diagram is shown

in Figure 2.

The RF input signal is fed to an internal preamplifier,

which provides gain and reverse isolation from the

divider signals. The output of the preamplifier interfaces

direct with the 15-bit fully programmable divider, which

is of MN+A architecture, where the dual modulus

prescaler is 8/9, the A counter is 3-bits, and the M

counter is 12 bits.

The output of the programmable divider is fed to the

phase comparator where it is compared in both phase

and frequency domain with the comparison frequency.

This frequency is derived either from the on-board

crystal controlled oscillator or from an external reference

source. In both cases the reference frequency is divided

down to the comparison frequency by the reference

divider which is programmable into 1 of 29 ratios as

detailed in Table 1.

The output of the phase detector feeds a charge pump

and loop amplifier section, which when used with an

external high voltage transistor and loop filter, integrates

the current pulses into the varactor line voltage.

The programmable divider output Fpd divided by two

can be switched to port P0 by programming the device

into test mode. The test modes are described in Table 4.

Programming

The SP5730 is controlled by an I2C data bus and is

compatible with both standard and fast mode formats

and with I2C data generated from nominal 3.3V and 5V

sources. The I2C logic level is selected by the bi-directional

port P3/LOGLEV. 5V logic levels are selected by

connecting P3/LOGLEV to Vcc or leaving open circuit

and 3.3V by connecting to ground. If this port is used as

an input the P3 data should be programmed to high

impedance. If used as an output 5V logic only levels can

be used and in this case the logic state imposed by the

port on the input is ignored.

Data and Clock are fed in on the SDA and SCL lines

respectively as defined by I2C bus format. The synthesiser

can either accept data (write mode), or send data (read

mode). The LSB of the address byte (R/W) sets the

device into write mode if it is low, and read mode if it is

high. Table 2 illustrates the format of the data. The

device can be programmed to respond to several

addresses, which enables the use of more than one

synthesiser in an I2C bus system. Table 3 shows how the

address is selected by applying a voltage to the ‘address’

input.

5

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