ATTL7581BAE データシートの表示（PDF） - Agere -> LSI Corporation

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ATTL7581BAE

Ringing Access Switch

Agere -> LSI Corporation 

L7581 Ringing Access Switch

Application

R1

TIP

CROWBAR

PROTECTION

RING

R2

SW3

SW1

SW4

SW2

Data Sheet

November 1999

VBAT

(REFERENCE)

SCR

AND

TRIP

CKT

TIP

BATTERY

FEED

RING

RING

GENERATOR

BATTERY

Figure 7. Typical RAS Application, A Version, Idle, or Talk State Shown

12-3074.e (F)

Table 12. Truth Table

INPUT

0V

5V

Don’t Care

TSD Tip Break Switch

5 V/Float1

On

5 V/Float1

Off

0 V2

Off

Ring Break Switch

On

Off

Off

1. Thermal shutdown mechanism is active with TSD floating or equal to 5 V.

2. Forcing TSD to ground overrides the logic input pins and forces an all OFF state.

3. Idle/Talk state.

4. Power ringing state.

5. All OFF state.

Ringing Return Switch

Off

On

Off

Ring Switch

Off3

On4

Off5

A parallel in/parallel out data latch is integrated into the L7581. Operation of the data latch is controlled by the logic

level input pin LATCH. The data input to the latch is the INPUT pin of the L7581, and the output of the data latch is

an internal node used for state control.

When the LATCH control pin is at logic 0, the data latch is transparent and data control signals flow directly from

INPUT, through the data latch to state control. Any changes in INPUT will be reflected in the state of the switches.

When the LATCH control pin is at logic 1, the data latch is active—the L7581 will no longer react to changes at the

INPUT control pin. The state of the switches is now latched; that is, the state of the switches will remain as they

were when the LATCH input transitioned from logic 0 to logic 1. The switches will not respond to changes in INPUT

as long as LATCH is held high.

Note that the TSD input is not tied to the data latch. TSD is not affected by the LATCH input. TSD input will override

state control via INPUT and LATCH.

12

Lucent Technologies Inc.

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