ML5800

DS5800-F-04

FINAL DATASHEET

JULY 2006

12

MODES OF OPERATION

The ML5800 has three key modes of operation:

STANDBY:

All circuits powered down, except the control interface (static CMOS)

RECEIVE:

Receiver circuits active

TRANSMIT:

Transmitter circuits active

MODE CONTROL

The two modes of operational are RECEIVE and TRANSMIT, controlled by RXON. XCEN is the chip enable/disable

control pin, which sets the device in operational or STANDBY modes. The relationship between the parallel control lines

and the mode of operation of the IC is summarized in Table 1.

XCEN

RXON

MODE NAME

FUNCTION

0

X

STANDBY

Control interfaces active, all other circuits powered down

1

1

RECEIVE

Receiver time slot

1

0

TRANSMIT

Transmit time slot

Table 1: Modes of Operation

STANDBY MODE

In STANDBY mode, the ML5800 transceiver is powered down. The only active circuits are the control interfaces, which

are static CMOS to minimize power consumption. The serial control interface and control registers remain powered up

and will accept and retain programming data as long as the VDD and VCCA are present. When exiting STANDBY

mode, remain in RECEIVE mode for at least 62.5

μs (typ) to allow for filter calibration.

RECEIVE MODE

In RECEIVE mode, the received signal at 5.8GHz is down converted, bandpass filtered (IF filter), fed to the frequency-

to-voltage converter, and low-pass filtered. The output of the low-pass filter is available at both the AOUT_TPC pin and

to the on-chip data slicer, which outputs NRZ digital data to the DOUT pin. An RSSI voltage output indicates the RF

input signal level at the output of the IF filter.

Receive Signal Strength Indication (RSSI)

RSSI is an indication of field strength. It can be used by the system to determine transmit power control (conserve

battery life) and/or to determine if a given channel is occupied.

Automatic Filter Alignment

When the chip is powered up the tuning information is reset to mid-range. In the first 62.5

μs of RECEIVE mode (RXON

set high) the ML5800 performs filter self-calibration, which tunes all the internal filters relative to the signal on the FREF

pin. Valid data is received after calibration is completed. Self-calibration sets:

Discriminator center frequency

IF filter center frequency and bandwidth

Receiver data low-pass filter bandwidth

Transmit data low-pass filter bandwidth