AM79M574 Datasheet, PDF (1/20 Pages) List of Unclassifed Manufacturers – Metering Subscriber Line Interface Circuit

Am79M574
Metering Subscriber Line Interface Circuit
DISTINCTIVE CHARACTERISTICS

Programmable constant-resistance feed

Programmable loop-detect threshold

Ground-key detect

Performs polarity reversal

Line-feed characteristics independent of
battery variations

Test relay driver optional

Supports 2.2 Vrms metering (12 and 16 kHz)

On-chip switching regulator for low-power
dissipation

Two-wire impedance set by single external
impedance

Tip Open state for ground-start lines

On-hook transmission
BLOCK DIAGRAM
A(TIP)
Ring Relay Driver
Test Relay Driver
HPA
Two-Wire
Interface
Ground-Key
Detector
Input Decoder
and Control
HPB
Signal Transmission
Off-Hook Detector
B(RING)
DA
DB
VREG
L
VBAT
BGND
Power-Feed
Controller
Switching Regulator
Ring-Trip Detector
CHS QBAT CHCLK
VCC VEE AGND
Notes:
1. Am79M574—E0 and E1 inputs; ring and test relay drivers sourced internally to BGND.
2. Current gain (K₁) = 1000.
RINGOUT
TESTOUT
C1
C2
C3
C4
E1
E0
DET
VTX
RSN
RD
RDC
16857C-001
Publication# 080135 Rev: E Amendment: /0
Issue Date: October 1999