5

MV1442

Input to crystal oscillator amplifier when in internal clock regeneration mode with the

crystal connected between pins 10 and 12. Alternatively this pin may be used as the 16384/

12.352MHz input to the internal clock regeneration circuitry if one oscillator is shared

between several decoders. This pin has no function when external clock regeneration is

selected and should in that case be tied to GND.

Output from the error detector circuit. This output goes high for one period of Decoder clock

one period after the detection of an HDB3 violation of the same polarity as the previous

HDB3 violation.

In external clock regeneration mode, this pin is used to output the OR function of the two

HDB3 inputs RXD1 and RXD2 (or TXD1 and TXD2) if loop test mode is selected; to an

external clock regeneration circuit in internal clock regeneration mode. This is the output

which forms the crystal oscillator with pin 10.

HDB3 input to Decoder block. This input asynchronously latches the incoming HDB3

encoded data and is falling edge sensitive.

Input pin for selection of normal or loop back operation. A logic ‘0’ on this pin selects

normal operation with encoder and decoder being independent and asynchronous. A

logic ‘1’ on this pin internally connects TXD1 to RXD1 and TXD2 to RXD2. Note that

in loop back mode a decoder clock must be supplied (or regenerated from pin 12 along

with the encoder clock.

HDB3 input 2 to Decoder block. See pin 13 description.

HDB3 encoded output from Encoder block. This output goes high after the rising edge of

clock if a mark is to be transmitted. The length of the pulse is set by the positive clock puIse

width.

HDB3 encoded output 2. See pin 16 description.

Digital supply voltage. 5V

±10%.

Electrical Characteristics

These Characteristics are guaranteed by either production test or design. They apply within the specified ambient

temperature and supply voltage ranges unless otherwise stated.

Static Characteristics

Low level input voltage

High level input voltage

Low level output voltage

High level output voltage

Input leakage current

Supply current (note 1)

Input capacitance

Output capacitance

Characteristic

Typ.

Conditions

0

2

2·4

-10

5

5

0·8

0·4

+200

15

5

15

Units

Min.

Max.

V

V

V

V

V

µA

mA

mA

mA

pF

pF

1.544/2.048MHz, with internal clock regeneration

1.544/2.048MHz, with external clock regeneration

8.448MHz operation

All inputs

All outputs

Symbol

NOTES

1. All supply currents are specified with outputs unloaded. These currents are not tested but are guaranteed by characterisation and

a static current test.

Value

Pin

Signal name

Description

CRYSTAL IN

DOUBLE VIOLATION

CRYSTAL OUT/CDR

RXD1

LOOP TEST ENABLE

RXD2

TXD1

TXD2

10

11

12

13

14

15

16

17

18

Table 1 - Pin descriptions (continued)