LE79555-1FQCT datasheet, PDF - EEWORLD Datasheet

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LE79555-1FQCT: DescriptionSLIC, 8 X 8 MM, GREEN, MO-220, QFN-32; CategoryWireless rf/communication Telecom circuit; File Size651KB，25 Pages; ManufacturerLegerity

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LE79555-1FQCT Overview

SLIC, 8 X 8 MM, GREEN, MO-220, QFN-32

LE79555-1FQCT Parametric

Parameter Name	Attribute value
Maker	Legerity
Parts packaging code	QFN
package instruction	HVQCCN,
Contacts	32
Reach Compliance Code	unknow
JESD-30 code	S-XQCC-N32
length	8 mm
Number of functions	1
Number of terminals	32
Maximum operating temperature	70 °C
Minimum operating temperature
Package body material	UNSPECIFIED
encapsulated code	HVQCCN
Package shape	SQUARE
Package form	CHIP CARRIER, HEAT SINK/SLUG, VERY THIN PROFILE
Certification status	Not Qualified
Maximum seat height	1 mm
Nominal supply voltage	5 V
surface mount	YES
Telecom integrated circuit types	SLIC
Temperature level	COMMERCIAL
Terminal form	NO LEAD
Terminal pitch	0.8 mm
Terminal location	QUAD
width	8 mm

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™

Le79555

Subscriber Line Interface Circuit

VE580 Series

APPLICATIONS

Ideal for high-density, low-power linecard applications

DESCRIPTION

The Le79555 device, part of Legerity’s VoiceEdge™ family

VE580 series of devices, was designed for high-density POTS

applications requiring a power saving, small footprint SLIC

device. The new SLIC device fulfills today's requirements for

POTS linecard markets requiring a balance of high-

performance cost-effective silicon components. The Le79555

device delivers economical linecard solutions by offering power

and space savings to linecard designers. The on-chip

switching regulator allows for power dissipation to be

minimized for the entire system. Another benefit is that the

device is offered in a reduced footprint package type, a 44-pin

TQFP. This small footprint saves designers board space, thus

increasing the density or number of lines on the board.

Legerity offers a range of compatible SLAC™ devices

providing a complete line circuit that can be optimized for

varying requirements. The SLIC device is designed to operate

with a range of SLAC devices from low cost, non-

programmable to more advanced, highly programmable

options viable for a range of applications.

FEATURES

Control states: Active, Reverse Polarity, Tip Open,

Ringing, Standby, and Open Circuit

Low Standby power

–40 to –58 V battery operation

On-hook transmission

Two-wire impedance set by single external impedance

Programmable constant-current feed

Low Off-Hook Active Overhead Voltage

Programmable loop-detect threshold

Ground-start detector

Programmable ring-trip detect threshold

No –5 V supply required

Three on-chip relay drivers and relay snubbers, one

ringing and two general purpose

Tip Open state for ground-start lines

On-chip switching regulator for Low power dissipation

Supports 30 mA for Active, Norma,l and Reverse

Polarity operation

RELATED LITERATURE

080125 SLIC Switcher Circuit Application Note

080725 Le79555 Switching Regulator Applications

080753 Le58QL02/021/031 QLSLAC™ Data Sheet

080754 Le58QL061/063 QLSLAC™ Data Sheet

ORDERING INFORMATION

Standard Packages

Device

Le79555-1VC

Le79555-1QC

Le79555-2VC

Le79555-2QC

Le79555-3VC

Le79555-3QC

Le79555-4VC

Le79555-4QC

Device

Le79555-1BVC

Le79555-1FQC

Le79555-2BVC

Le79555-2FQC

Le79555-3BVC

Le79555-3FQC

Le79555-4BVC

Le79555-4FQC

Performance Grade/Package

52 dB Pol. Rev., 44-pin TQFP

52 dB Pol. Rev., 32-pin QFN

63 dB Pol. Rev., 44-pin TQFP

63 dB Pol. Rev., 32-pin QFN

52 dB No Pol. Rev., 44-pin TQFP

52 dB No Pol. Rev., 32-pin QFN

63 dB No Pol. Rev., 44-pin TQFP

63 dB No Pol. Rev., 32-pin QFN

Green Packages

Performance Grade/Package

52 dB Pol. Rev., 44-pin TQFP

52 dB Pol. Rev., 32-pin QFN

63 dB Pol. Rev., 44-pin TQFP

63 dB Pol. Rev., 32-pin QFN

52 dB No Pol. Rev., 44-pin TQFP

52 dB No Pol. Rev., 32-pin QFN

63 dB No Pol. Rev., 44-pin TQFP

63 dB No Pol. Rev., 32-pin QFN

Packing

Tray

Packing

Tray

BLOCK DIAGRAM

Ring Relay Driver

RINGOUT

A(TIP)

Relay Driver

RYOUT1

Tray

Relay Driver

RYOUT2

Tray

HPA

Input Decoder

and Control

Two Wire

Interface

DET

Ground

Detector

HPB

Signal

Transmission

B(RING)

Off-Hook

Detector

VTX

RSN

Tray

VREG

Power Feed

Controller

RDC

CAS

VDC

The green package meets RoHS Directive 2002/95/EC of the

European Council to minimize the environmental impact of

electrical equipment.

For delivery using a tape and reel packing system, add a "T" suffix

to the OPN (Ordering Part Number) when placing an order.

Ring-Trip

Detector

Switching Regulator

VBAT

BGND

CHCLK

Document ID#

080686

Date:

Rev:

Version:

Distribution:

Public Document

AGND

QBAT

RSVD

CHS

VCC

Aug 29, 2005

TABLE OF CONTENTS

Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Related Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Block Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Two-Wire Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Ground Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Signal Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Power Feed Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Switching Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Input Decoder and Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Off-Hook Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Ring-Trip Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Ring Relay Driver. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Relay Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Connection Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Operating Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Transmission Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Longitudinal Capability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Idle Channel Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Insertion Loss and Balance Return Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Line Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Power Supply Rejection Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Supply Currents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

RFI Rejection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Receive Summing Node (RSN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Logic Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Logic Output DET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Ring-Trip Detector Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Loop Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Relay Driver Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

DC Feed Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Test Circuit Scenarios. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

APPLICATION CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Line card Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Physical Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

44-Pin TQFP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

32-Pin QFN (8x8). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Revision C1 to C2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Revision C2 to D1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Revision D1 to E1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Le79555 VE580 Series Data Sheet

PRODUCT DESCRIPTION

The Le79555 device is designed for short loop and long loop high-density POTS applications requiring a power saving, small

footprint SLIC. The Le79555 device boasts increased power savings over Legerity's other POTS solutions by using an internal

switching regulator for each channel to enhance system power management. The switching regulator eliminates the need for a

second voltage supply, commonly required for SLIC devices in POTS applications. Such elimination passes on board space and

cost savings to the designers. Thus, the smaller footprint and added features of the Le79555 device allows customers to amortize

the cost of common hardware across more channels and increase the line density per board. Additionally, the Le79555 device

gives line card designers a simple control interface that supports six control states: Active, Ringing, Standby, Disconnect, Reverse

Polarity, and Tip Open. The Le79555 device is a low cost, high performance device providing key features required for POTS

markets worldwide, including: low power dissipation and ground key detection, as well as all of the features offered currently by

Legerity's Transformer SLIC family, Le7920/22.

BLOCK DESCRIPTIONS

Two-Wire Interface

The two-wire interface provides DC current and sends voice signals to a telephone apparatus connected to the line card with a

two-wire line. The two-wire interface also receives the returning voice signals from the telephone.

Ground Detector

The ground detector block performs ground start and ground key detection, as well as automatically detects a ring-ground fault.

Therefore, when the longitudinal current is greater than the ground key detector threshold, IGK, in either Active, Standby, or Tip

Open, the DET will go low. Note that when the device is in Active or Standby, DET may be an indication of off-hook, ground fault,

or both.

Signal Transmission

The RSN input current controls the receive current sent to the two-wire interface. The AC line voltage is sensed by differential

amplifiers between the A and HPA leads, and between HPB and B leads. The outputs of these amplifiers are equal to the AC

metallic components of the line voltages. The transmission circuit also contains a longitudinal feedback circuit to shunt

longitudinal signals to a DC bias voltage. The longitudinal feedback does not affect metallic signals.

Power Feed Controller

The power feed controller has three sections: (1) the battery feed circuit, (2) the reverse polarity circuit, and (3) the bias circuit.

The battery feed circuit regulates the amount of DC current and voltage supplied to the telephone over a wide range of loop

resistance. The reverse polarity circuit provides the capability to reverse the loop current for pay telephone key pad disable and

other applications. The bias circuit provides a reference voltage, which is offset from the subscriber line voltage. The reference

voltage controls the switched mode regulator, which minimizes SLIC power consumption by providing the minimum supply

voltage needed by the line drivers for proper operation.

Switching Regulator

A switching regulator function is implemented on the chip with a few external components. The power feed controller generates

a reference voltage which is the minimum voltage required to feed the output line amplifiers. The efficiency of the switching

regulator (>80%) minimizes both the on-chip power dissipation and the system power dissipation. This is particularly important

for short loops operating at high currents which otherwise cause high power dissipation.

Input Decoder and Control

The input decoder and control block provides a means for a microprocessor or SLAC IC to control such system functions as line

activate, on-hook transmission, ringing, and reverse polarity. The input decoder and control block has TTL-compatible inputs,

which set the operating states of the SLIC. It also provides the supervision signal sent back to the controller.

Off-Hook Detector

The most important loop monitoring function is off-hook detection. The two-wire interface produces a current equal in magnitude

to the loop current divided by a constant, and sends it out on the RD pin. An external resistor and capacitor (RD and CD) connect

the RD pin to ground. The value of the voltage across resistor R

is proportional to the current leaving the RD pin times the value

of R

. The DET pin will show a logic Low when this voltage rises above a threshold.

Le79555 VE580 Series Data Sheet

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