ATTL7557AAU 查看數據表（PDF） - Agere -> LSI Corporation

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ATTL7557AAU

Low-Power SLICs with Battery Switch

Agere -> LSI Corporation 

Data Sheet

January 2000

L7556, L7557 Low-Power SLICs

with Battery Switch

Pin Information (continued)

Table 1. Pin Descriptions (continued)

Pin Symbol Type

Description

11

PR I/O Protected Ring. The output of the ring driver amplifier and input to loop sensing cir-

cuitry. Connect to loop through overvoltage protection.

12 CF2 — Filter Capacitor 2. Connect a 0.1 µF capacitor from this pin to AGND.

13 CF1 — Filter Capacitor 1. Connect a 0.47 µF capacitor from this pin to pin CF2.

14 VITR O Transmit ac Output Voltage. This output is a voltage that is directly proportional to the

differential tip/ring current.

15 ICM

I Common-Mode Current Sense. To program ring ground sense threshold, connect a

resistor to VCC and connect a capacitor to AGND to filter 50/60 Hz. If unused, the pin

can be left unconnected.

16 RGDET O Ring Ground Detect. When high, this open-collector output indicates the presence of

a ring ground. To use, connect a 100 kΩ resistor to VCC.

17

B0

I State Control Input. B0 and B1 determine the state of the SLIC. See Table 2.

18 AGND — Analog Signal Ground.

19 AGND — Analog Signal Ground.

20 DCR

I dc Resistance for Low Loop Currents. Leave open for dc feed resistance of 115 Ω,

or short to DCOUT for 615 Ω. Intermediate values can be set by a simple resistor

divider from DCOUT to ground with the tap at DCR.

21 BGND — Battery Ground. Ground return for the battery supply.

22

PT I/O Protected Tip. The output of the tip driver amplifier and input to loop sensing circuitry.

Connect to loop through overvoltage protection.

23 RTSN

I Ring Trip Sense Negative. Connect this pin to the ringing generator signal through a

high-value resistor.

24 RTSP

I Ring Trip Sense Positive. Connect this pin to the ring relay and the ringer series resis-

tor through a high-value resistor.

25 NRDET O Ring Trip Detector Output. When low, this logic output indicates that ringing is tripped.

26 NLC O Loop Detector Output. When low, this logic output indicates an off-hook condition.

27

B1

I/O State Control Input. B0 and B1 determine the state of the SLIC. See Table 2. Pin B1

has a 40 kΩ pull-up. It goes low in the event of thermal shutdown.

28 XMT O Transmit ac Output Voltage. The output of the uncommitted operational amplifier.

29

SN

I Summing Node. The inverting input of the uncommitted operational amplifier. A resis-

tor or network to XMT sets the gain.

30

NC

— No Connection. Do not use as a tie point.

31 BS2 — Battery Switch Slowdown. A 0.1 µF capacitor from BS1 to BS2 will ramp the battery

switch transition for applications requiring quiet transition. If not needed, the pin can be

left open.

32 BS1 — Battery Switch Slowdown. A 0.1 µF capacitor from BS1 to BS2 will ramp the battery

switch transition for applications requiring quiet transition. If not needed, the pin can be

left open.

Lucent Technologies Inc.

5

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