ST70136

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4.8 - Tone Detector

The tone detector is dedicated for remote activation. It operates during SUSPEND mode with PWD = 0

only. When the tone detector level received Vin over tone 40 or 72 is greater than 15

ACTD pin is set to wake up the modem.

ACTD pin is resetted when the AFE is back in full operating mode (SUSPEND = 0, PWD = 0). The maxi-

mum signal sensitivity at the Tone detector inputs is 50mV peak to peak.

4.9 - Mode Management

4.9.1 - General

The ST70136 can be used in a various range of ATU-R equipments, but a specific mode management

address USB application in its different modes.

In following table, "CPE" is an USB ADSL modem application done with a ST70136 AFE and a ST70137

DMT. The CPE is connected to an USB port of an equipment.

Table 8 : ST70136 / USB Operating Mode Configurations

SUSPEND

PWD

USB Mode Description

00

Active mode

The CPE application is in operative mode, its current consumption is less than 500 mA.

ST70136 is power-up, the Tone detector is OFF and CLKM output is enabled.

01

Enumerating mode

The CPE application is in the configuration process, plug in, its current consumption is

less than 100 mA.

ST70136 analog part is in power done mode, the digital part is enabled and CLKM

output is enabled.

10

Suspend mode after enumerating mode

After enumerating, the CPE application is in suspend mode, in this mode the CPE must

be able to wake up the equipment when a tone is received, its current consumption is

less than 2.5 mA.

ST70136 analog and digital parts are in power down mode, the Tone detector is

activated and CLKM output is disabled.

11

Stand by mode

The CPE is not configured and in stand by mode, it could be wake up only by the

equipment, its current consumption is less than 500

µA.

ST70136 is fully in stand by mode and CLKM is disabled.

Figure 5 : USB Power Management Operating Modes

Plug in

Enumerating mode

PWD = 1

SUSPEND = 0

Suspend mode

PWD = 0

SUSPEND = 1

Stand by mode

PWD = 1

SUSPEND = 1

Active mode

PWD = 0

SUSPEND = 0