Motorola MC145505L, MC145505P, MC145505DW, MC145502P, MC145503DW Datasheet

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MC145500•MC145501•MC145502•MC145503•MC145505MOTOROLA

  

The MC145500, MC145501, MC145502, MC145503, and MC145505 are all

per channel PCM Codec–Filter mono–circuits. These devices perform the voice

digitization and reconstruction as well as the band limiting and smoothing

required for PCM systems. The MC145500 and MC145503 are general

purpose devices that are offered in a 16–pin package. They are designed to

operate in both synchronous and asynchronous applications and contain an

on–chip precision reference voltage. The MC145501 is offered in an 18–pin

package and adds the capability of selecting from three peak overload voltages

(2.5, 3.15, and 3.78 V). The MC145505 is a synchronous device offered in a

16–pin DIP and wide body SOIC package intended for instrument use. The

MC145502 is the full–featured device which presents all of the options of the

chip. This device is packaged in a 22–pin DIP and a 28–pin chip carrier package

and contains all the features of the MC145500 and MC145501 plus several

more. Most of these features can be made available in a l ower pin count

package tailored to a specific user’s application. Contact the factory for further

details.

These devices are pin–for–pin replacements for Motorola’s first generation of

MC14400/01/02/03/05 PCM mono–circuits and are upwardly compatible with

the MC14404/06/07 codecs and other industry standard codecs. They also

maintain compatibility with Motorola’s family of MC33120 and MC3419 SLIC

products.

The MC145500 family of PCM Codec–Filter mono–circuits utilizes CMOS

due to its reliable low–power performance and proven capability for complex

analog/digital VLSI functions.

MC145500 (This Device is Not Recommended for New Designs)

• 16–Pin Package

• Transmit Bandpass and Receive Low–Pass Filter On–Chip

• Pin Selectable Mu–Law/A–Law Companding with Corresponding Data

Format

• On–Chip Precision Reference Voltage (3.15 V)

• Power Dissipation of 50 mW, Power–Down of 0.1 mW at ±

5 V

• Automatic Prescaler Accepts 128 kHz, 1.536, 1.544, 2.048, and 2.56 MHz

for Internal Sequencing

MC145501 — All of the Above Plus:

(This Device is Not Recommended for New Designs)

• 18–Pin Package

• Selectable Peak Overload Voltages (2.5, 3.15, 3.78 V)

• Access to the Inverting Input of the TxI Input Operational Amplifier

MC145502 — All of the Above Plus:

• 22–Pin and 28–Pin Packages

• Variable Data Clock Rates (64 kHz to 4.1 MHz)

• Complete Access to the Three Terminal Transmit Input Operational

Amplifiers

• An External Precision Reference May Be Used

MC145503 — All of the Above Features of the MC145500 Plus:

• 16–Pin Package

• Complete Access to the Three Terminal Transmit Input Operational Amplifiers

MC145505 — Same as MC145503 Except:

• 16–Pin Package

• Common 64 kHz to 4.1 MHz Transmit/Receive Data Clock

Order this document

by MC145500/D



SEMICONDUCTOR TECHNICAL DATA











L SUFFIX

CERAMIC PACKAGE

CASE 620

MC145500/03/05

P SUFFIX

PLASTIC DIP

CASE 648

MC145503/05

L SUFFIX

CERAMIC PACKAGE

CASE 726

MC145501

L SUFFIX

CERAMIC PACKAGE

CASE 736

MC145502

P SUFFIX

PLASTIC DIP

CASE 708

MC145502

DW SUFFIX

SOG PACKAGE

CASE 751G

MC145503/05

FN SUFFIX

PLCC PACKAGE

CASE 776

MC145502

 Motorola, Inc. 1995

REV 1

9/95 (Replaces ADI1287)

MC145500•MC145501•MC145502•MC145503•MC145505 MOTOROLA

MC145500/01/02/03/05 PCM CODEC–FILTER MONO–CIRCUIT BLOCK DIAGRAM

RCE

RDC

RECEIVE SHIFT

D/A

SHARED

DAC

1, 12, 16, 20

CCI PRESCALER

SEQUENCE

AND

CONTROL

TRANSMIT SHIFT

CCI

MSI

PDI

TDD

TDE

TDC

2.5 V

REF

RSI

CIRCUITRY

A/D

FREQUENCY

Controlled by V

Rx ≈

100 kΩ (internal resistors)

RxO

RxG

RxO

ref

RSI

TxI

– Tx

+ Tx

400

RDD

–

NOTES:

MC145500•MC145501•MC145502•MC145503•MC145505MOTOROLA

PIN ASSIGNMENTS

(DRAWINGS DO NOT REFLECT RELATIVE SIZE)

+ Tx

RxG

RxO

ref

– Tx

TxI

RxO

PDI

Mu/A

RDC

RCE

RDD

RSI

MSI

TDE

TDD

CCI

MC145502L, P

125

RDC

RCE

RDD

MSI

TDE

TDD

TxI

RxO

PDI

Mu/A

TxI

RxO

RSI

PDI

Mu/A

– Tx

RxO

RDC

RCE

RDD

MSI

TDE

TDD

TDC

MC145500L MC145501LMC145503L, P

MC145505L, P

TDC

MC145503DW MC145505DW

28–PIN PQLCC

(TOP VIEW)

TDC

125

RDC

RCE

RDD

TDE

TDD

TxI

+ Tx

RxO

PDI

Mu/A

– Tx

TDC

125

DCLK

RCE

RDD

TDE

TDD

TxI

+ Tx

RxO

PDI

Mu/A

– Tx

CCI

125

RDC

RCE

RDD

TDE

TDD

TxI

+ Tx

RxO

PDI

Mu/A

– Tx

TDC

125

DCLK

RCE

RDD

TDE

TDD

TxI

+ Tx

RxO

PDI

Mu/A

– Tx

CCI

4 3 2 1 28 27 26

12 13 14 15 16 17 18

+ Tx

RxO

RxG

– Tx

TxI

TDC

RDC

RCE

TDD

CCI

Mu/A

PDI

MSI

TDE

RxO

RSI

RDD

ref

NC = NO CONNECTION

MC145502FN

MC145500•MC145501•MC145502•MC145503•MC145505 MOTOROLA

ABSOLUTE MAXIMUM RATINGS (Voltage Referenced to V

)

Rating

Symbol Value Unit

DC Supply Voltage V

, V

– 0.5 to 13 V

Voltage, Any Pin to V

V – 0.5 to V

+ 0.5 V

DC Drain Per Pin (Excluding V

, V

) I 10 mA

Operating Temperature Range T

– 40 to + 85 °C

Storage Temperature Range T

stg

– 85 to + 150 °C

RECOMMENDED OPERATING CONDITIONS (T

= – 40 to + 85°C)

Characteristic

Min Typ Max Unit

DC Supply Voltage

Dual Supplies: V

= – V

, (V

= V

= 0 V)

Single Supply: V

to V

is an Output, V

= V

or V

)

MC145500, MC145501, MC145502, MC145503, MC145505 (Using Internal

3.15 V Reference)

MC145501, MC145502 Using Internal 2.5 V Reference

MC145501, MC145502 Using Internal 3.78 V Reference

MC145502 Using External 1.5 V Reference, Referenced to V

4.75

8.5

7.0

9.5

4.75

5.0

—

6.3

12.6

Power Dissipation

CMOS Logic Mode (V

to V

= 10 V, V

= V

)

TTL Logic Mode (V

= + 5 V, V

= – 5 V, V

= V

= 0 V)

—

Power Down Dissipation — 0.1 1.0 mW

Frame Rate Transmit and Receive 7.5 8.0 8.5 kHz

Data Rate

MC145500, MC145501, MC145503

Must Use One of These Frequencies, Relative to MSI Frequency of 8 kHz

—

128

1536

1544

2048

2560

—

kHz

Data Rate for MC145502, MC145505 64 — 4096 kHz

Full Scale Analog Input and Output Level

MC145500, MC145503, MC145505

MC145501, MC145502 (V

ref

= V

) RSI = V

RSI = V

MC145502 Using an External Reference Voltage Applied at V

ref

Pin RSI = V

RSI = V

—

3.15

3.78

3.15

2.5

1.51 x V

ref

1.26 x V

ref

—

DIGITAL LEVELS (V

to V

= 4.75 V to 12.6 V, T

= – 40 to + 85°C)

Characteristic

Symbol Min Max Unit

Input Voltage Levels (TDE, TDC, RCE, RDC, RDD, DC, MSI, CCI, PDI)

CMOS Mode (V

= V

, V

is Digital Ground) “0”

“1”

TTL Mode (V

≤

– 4.0 V, V

is Digital Ground) “0”

“1”

—

0.7 x V

—

+ 2.0 V

0.3 x V

—

+ 0.8 V

—

Output Current for TDD (Transmit Digital Data)

CMOS Mode (V

= V

, V

= 0 V and is Digital Ground)

= 5 V, V

out

= 0.4 V)

= 10 V, V

out

= 0.5 V)

= 5 V, V

out

= 4.5 V)

= 10 V, V

out

= 9.5 V)

TTL Mode (V

≤

– 4.75 V, V

= 0 V and is Digital Ground) (V

= 0.4 V)

= 2.4 V)

1.0

3.0

– 1.0

– 3.0

1.6

– 0.2

—

This device contains circuitry to protect

against damage due to high static voltages or

electric fields; however, it is advised that

normal precautions be taken to avoid applica-

tion of any voltage higher than maximum rated

voltages to this high impedance circuit. For

proper operation it is recommended that V

and V

out

be constrained to the range V

≤ (V

or V

out

) ≤ V

Unused inputs must always be tied to an

appropriate logic voltage level (e.g., V

, V

, or V

MC145500•MC145501•MC145502•MC145503•MC145505MOTOROLA

ANALOG TRANSMISSION PERFORMANCE

= + 5 V ± 5%, V

= – 5 V ± 5%, V

= V

= 0 V, V

ref

= RSI = V

(Internal 3.15 V Reference), 0 dBm0 = 1.546 Vrms = + 6 dBm @

600 Ω, T

= – 40 to + 85°C, TDC = RDC = CC = 2.048 MHz, TDE = RCE = MSI = 8 kHz, Unless Otherwise Noted)

End–to–End A/D D/A

Characteristic

Min Max Min Max Min Max Unit

Absolute Gain (0 dBm0 @ 1.02 kHz, T

= 25°C, V

= 5 V, V

= – 5 V) — — – 0.30 + 0.30 – 0.30 + 0.30 dB

Absolute Gain Variation with Temperature 0 to + 70°C — — — ± 0.03 — ± 0.03 dB

Absolute Gain Variation with Temperature – 40 to +85°C — — — ± 0.1 — ± 0.1 dB

Absolute Gain Variation with Power Supply (V

= 5 V, V

= – 5 V, 5%) — — — ± 0.02 — ± 0.02 dB

Gain vs Level Tone (Relative to – 10 dBm0, 1.02 kHz) + 3 to – 40 dBm0

– 40 to – 50 dBm0

– 50 to – 55 dBm0

– 0.4

– 0.8

– 1.6

+ 0.4

+ 0.8

+ 1.6

– 0.2

– 0.4

– 0.8

+ 0.2

+ 0.4

+ 0.8

– 0.2

– 0.4

– 0.8

+ 0.2

+ 0.4

+ 0.8

Gain vs Level Pseudo Noise (A–Law Relative to – 10 dBm0)

CCITT G.714 – 10 to – 40 dBm0

– 40 to – 50 dBm0

– 50 to – 55 dBm0

—

– 0.25

– 0.30

– 0.45

+ 0.25

+ 0.30

+ 0.45

– 0.25

– 0.30

– 0.45

+ 0.25

+ 0.30

+ 0.45

Total Distortion – 1.02 kHz Tone (C–Message) 0 to – 30 dBm0

– 40 dBm0

– 45 dBm0

—

dBC

Total Distortion With Pseudo Noise (A–Law) – 3 dBm0

CCITT G.714 – 6 to – 27 dBm0

– 34 dBm0

– 40 dBm0

– 55 dBm0

27.5

33.1

28.2

13.2

—

35.5

33.5

28.5

13.5

—

28.5

34.2

30.0

15.0

—

Idle Channel Noise (For End–End and A/D, See Note 1)

Mu–Law, C–Message Weighted

A–Law, Psophometric Weighted

—

– 69

—

– 69

—

– 78

dBrnC0

dBm0p

Frequency Response (Relative to 1.02 kHz @ 0 dBm0) 15 to 60 Hz

300 to 3000 Hz

3400 Hz

4000 Hz

≥ 4600 Hz

—

– 0.3

– 1.6

—

– 23

+ 0.3

– 28

– 60

—

– 0.15

– 0.8

—

– 23

+ 0.15

– 14

– 32

—

– 0.15

– 0.8

—

0.15

+ 0.15

– 14

– 30

Inband Spurious (1.02 kHz @ 0 dBm0, Transmit and RxO)

300 to 3000 Hz

— — — – 43 — – 43 dBm0

Out–of–Band Spurious at RxO (300 – 3400 Hz @ 0 dBm0 In)

4600 to 7600 Hz

7600 to 8400 Hz

8400 to 100,000 Hz

—

– 30

– 40

– 30

—

– 30

– 40

– 30

Idle Channel Noise Selective @ 8 kHz, Input = V

, 30 Hz Bandwidth — – 70 — — — – 70 dBm0

Absolute Delay @ 1600 Hz (TDC = 2.048 MHz, TDE = 8 kHz) — — — 310 — 180 µs

Group Delay Referenced to 1600 Hz (TDC = 2048 kHz,

TDE = 8 kHz) 500 to 600 Hz

600 to 800 Hz

800 to 1000 Hz

1000 to 1600 Hz

1600 to 2600 Hz

2600 to 2800 Hz

2800 to 3000 Hz

—

200

140

110

170

– 40

– 30

– 20

—

120

160

µs

Crosstalk of 1020 Hz @ 0 dBm0 From A/D or D/A (Note 2) — — — – 75 — – 80 dB

Intermodulation Distortion of Two Frequencies of Amplitudes – 4 to

– 21 dBm0 from the Range 300 to 3400 Hz

— — — – 41 — – 41 dB

NOTES:

1. Extrapolated from a 1020 Hz @ – 50 dBm0 distortion measurement to correct for encoder enhancement.

2. Selectively measured while the A/D is stimulated with 2667 Hz @ – 50 dBm0.

MC145500•MC145501•MC145502•MC145503•MC145505 MOTOROLA

ANALOG ELECTRICAL CHARACTERISTICS (V

= – V

= 5 V to 6 V ± 5%, T

= – 40 to + 85°C)

Characteristic Symbol Min Typ Max Unit

Input Current +Tx, –Tx (Txl for MC145500) I

— ± 0.01 ± 0.2 µA

AC Input Impedance to V

(1 kHz) +Tx, –Tx

Txl for MC145500

0.1

0.2

—

MΩ

Input Capacitance +Tx, –Tx — — 10 pF

Input Offset Voltage of Txl Op Amp — < ± 30 — mV

Input Common Mode Voltage Range +Tx, –Tx V

ICR

+ 1.0 — V

– 2.0 V

Input Common Mode Rejection Ratio +Tx, –Tx CMRR — 70 — dB

Txl Unity Gain Bandwidth R

≥ 10 kΩ BW

— 1000 — kHz

Txl Open Loop Gain R

≥ 10 kΩ A

VOL

— 75 — dB

Equivalent Input Noise (C–Message) Between +Tx and –Tx, at Txl — – 20 — dBrnC0

Output Load Capacitance for Txl Op Amp 0 — 100 pF

Output Voltage Range Txl Op Amp, RxO or RxO

= 10 kΩ to V

= 600 Ω to V

out

+ 0.8

+ 1.5

—

– 1.0

– 1.5

Output Current Txl, RxO, RxO V

+ 1.5 V ≤ V

out

≤ V

– 1.5 V

± 5.5 — — mA

Output Impedance RxO, RxO* 0 to 3.4 kHz Z

out

— 3 — Ω

Output Load Capacitance for RxO and RxO* 0 — 200 pF

Output dc Offset Voltage Referenced to V

Pin RxO

RxO

—

± 100

± 150

Internal Gainsetting Resistors for RxG to RxO and RxO 62 100 225 kΩ

External Reference Voltage Applied to V

ref

(Referenced to V

) 0.5 — V

– 1.0 V

ref

Input Current — — 20 µA

Output Bias Voltage — 0.53 V

0.47 V

— V

Output Current Source

Sink

VAG

0.4

10.0

—

0.8

—

Output Leakage Current During Power Down for the Txl Op Amp, V

RxO, and RxO

— — ± 30 µA

Positive Power Supply Rejection Ratio, Transmit

0 – 100 kHz @ 250 mV, C–Message Weighting Receive

—

dBC

Negative Power Supply Rejection Ratio, Transmit

0 – 100 kHz @ 250 mV, C–Message Weighting Receive

—

dBC

*Assumes that RxG is not connected for gain modifications to RxO.

MC145500•MC145501•MC145502•MC145503•MC145505MOTOROLA

MODE CONTROL LOGIC (V

to V

= 4.75 V to 12.6 V, T

= – 40 to + 85°C)

Characteristic

Min Typ Max Unit

Voltage for TTL Mode (TTL Logic Levels Referenced to V

) V

— V

– 4.0 V

Voltage for CMOS Mode (CMOS Logic Levels of V

to V

) V

– 0.5 — V

Mu/A Select Voltage

Mu–Law Mode

Sign Magnitude Mode

A–Law Mode

– 0.5

—

+ 0.5

RSI Voltage for Reference Select Input (MC145501 and MC145502) 3.78 V Mode

2.5 V Mode

3.15 V Mode

– 0.5

—

+ 0.5

ref

Voltage for Internal or External Reference (MC145502 Only)

Internal Reference Mode

External Reference Mode

+ 0.5

—

+ 0.5

– 1.0

Analog Test Mode Frequency, MS = CCI (MC145500, MC145501, MC145502 Only)

See Pin Description; Test Modes

— 128 — kHz

SWITCHING CHARACTERISTICS (V

to V

= 9.5 V to 12.6 V, T

= – 40 to + 85°C, C

= 150 pF, CMOS or TTL Mode)

Characteristic

Symbol Min Typ Max Unit

Output Rise Time TDD

Output Fall Time

TLH

THL

—

Input Rise Time TDE, TDC, RCE, RDC, DC, MSI, CCI

Input Fall Time

TLH

THL

—

µs

Pulse Width TDE Low, TDC, RCE, RDC, DC, MSI, CCI t

100 — — ns

DCLK Pulse Frequency (MC145502/05 Only) TDC, RDC, DC f

64 — 4096 kHz

CCI Clock Pulse Frequency (MSI = 8 kHz)

CCI is internally tied to TDC on the MC145500/01/03, therefore, the

transmit data clock must be one of these frequencies. This pin will accept

one of these discrete clock frequencies and will compensate to produce

internal sequencing.

CL1

CL2

CL3

CL4

CL5

—

128

1536

1544

2048

2560

—

kHz

Propagation Delay Time

TDE Rising to TDD Low Impedance TTL

CMOS

TDE Falling to TDD High Impedance TTL

CMOS

TDC Rising Edge to TDD Data, During TDE High TTL

CMOS

TDE Rising Edge to TDD Data, During TDC High TTL

CMOS

—

180

150

180

150

180

150

TDC Falling Edge to TDE Rising Edge Setup Time t

su1

20 — — ns

TDE Rising Edge to TDC Falling Edge Setup Time t

su2

100 — — ns

TDE Falling Edge to TDC Rising Edge to Preserve the Next TDD Data t

su8

20 — — ns

RDC Falling Edge to RCE Rising Edge Setup Time t

su3

20 — — ns

RCE Rising Edge to RDC Falling Edge Setup Time t

su4

100 — — ns

RDD Valid to RDC Falling Edge Setup Time t

su5

60 — — ns

CCI Falling Edge to MSI Rising Edge Setup Time t

su6

20 — — ns

MSI Rising Edge to CCI Falling Edge Setup Time t

su7

100 — — ns

RDD Hold Time from RDC Falling Edge t

100 — — ns

TDE, TDC, RCE, RDC, RDD, DC, MSI, CCI Input Capacitance — — 10 pF

TDE,TDC, RCE, RDC, RDD, DC, MSI, CCI Input Current — ± 0.01 ± 10 µA

TDD Capacitance During High Impedance (TDE Low) — 12 15 pF

TDD Input Current During High Impedance (TDE Low) — ± 0.1 ± 10.0 µA

MC145500•MC145501•MC145502•MC145503•MC145505 MOTOROLA

DEVICE DESCRIPTIONS

A codec–filter is a device which is used for digitizing and

reconstructing the human voice. These devices were devel-

oped primarily for the telephone network to facilitate voice

switching and transmission. Once the voice is digitized, it

may be switched by digital switching methods or transmitted

long distance (T1, microwave, satellites, etc.) without degra-

dation. The name codec is an acronym from “Coder” for the

A/D used to digitize voice, and “Decoder” for the D/A used for

reconstructing voice. A codec is a single device that does

both the A/D and D/A conversions.

To digitize intelligible voice requires a signal to distortion of

about 30 dB for a dynamic range of about 40 dB. This may be

accomplished with a linear 13–bit A/D and D/A, but will far

exceed the required signal to distortion at amplitudes greater

than 40 dB below the peak amplitude. This excess perform-

ance is at the expense of data per sample. Two methods of

data reduction are implemented by compressing the 13–bit

linear scheme to companded 8–bit schemes. These com-

panding schemes follow a segmented or “piecewise–linear”

curve formatted as sign bit, three chord bits, and four step

bits. For a given chord, all 16 of the steps have the same volt-

age weighting. As the voltage of the analog input increases,

the four step bits increment and carry to the three chord bits

which increment. With the chord bits incremented, the step

bits double their voltage weighting. This results in an effec-

tive resolution of 6–bits (sign + chord + four step bits) across

a 42 dB dynamic range (7 chords above zero, by 6 dB per

chord). There are two companding schemes used; Mu–255

Law specifically in North America, and A–Law specifically in

Europe. These companding schemes are accepted world

wide. The tables show the linear quantization levels to PCM

words for the two companding schemes.

In a sampling environment, Nyquist theory says that to

properly sample a continuous signal, it must be sampled at a

frequency higher than twice the signal’s highest frequency

component. Voice contains spectral energy above 3 kHz, but

its absence is not detrimental to intelligibility. To reduce the

digital data rate, which is proportional to the sampling rate, a

sample rate of 8 kHz was adopted, consistent with a band-

width of 3 kHz. This sampling requires a low–pass filter to

limit the high frequency energy above 3 kHz from distorting

the i nband signal. T he telephone line is a lso subject to

50/60 Hz power line coupling which must be attenuated from

the signal by a high–pass filter before the A/D converter.

The D/A process reconstructs a staircase version of the

desired inband signal which has spectral images of the in-

band signal modulated about the sample frequency and its

harmonics. These spectral images are called aliasing com-

ponents which need to be attenuated to obtain the desired

signal. The low–pass filter used to attenuate filter aliasing

components is typically called a reconstruction or smoothing

filter.

The MC145500 series PCM Codec–Filters have the co-

dec, both presampling and reconstruction filters, a precision

voltage reference on chip, and require no external compo-

nents. There a re five distinct versions o f the Motorola

MC145500 Series.

MC145500

The MC145500 PCM Codec–Filter is intended for stan-

dard byte interleaved synchronous and asynchronous appli-

cations. The TDC pin on this device is the input to both the

TDC and CCI functions in the pin description. Consequently,

for MSI = 8 kHz, TDC can be one of five discrete frequencies.

These are 128 kHz (40 to 60% duty cycle) 1.536, 1.544,

2.048, or 2.56 MHz. (For other data clock frequencies, see

MC145502 or MC145505.) The internal reference is set for

3.15 V peak full scale, and the full scale input level at Txl and

output level at RxO is 6 .3 V peak–to–peak. This is the

+ 3 dBm0 level of the PCM Codec–Filter. All other functions

are described in the pin description.

MC145501

The MC145501 PCM Codec–Filter offers the same fea-

tures and is for the same application as the MC145500, but

offers two additional pins and features. The reference select

input allows the full s cale level of the device to be set at

2.5 Vp, 3.15 Vp, or 3.78 Vp. The –Tx pin allows for external

transmit g ain adjust a nd simplifies the i nterface t o the

MC3419 SLIC. Otherwise, it is identical to MC145500.

MC145502

The MC145502 P CM Codec–Filter is the full f eature

22–pin device. It is intended for use in applications requiring

maximum flexibility. The MC145502 contains all the features

of the M C145500 and M C145501. The M C145502 is in-

tended for bit interleaved or byte interleaved applications

with data clock frequencies which are nonstandard or time

varying. One of the five standard frequencies (listed above)

is applied to the CCI input, and the data clock inputs can be

any frequency between 64 kHz and 4.096 MHz. The V

ref

allows for use of an external shared reference or selection of

the internal reference. The RxG pin accommodates gain ad-

justments for the inverted analog output. All three pins of the

input gain–setting operational amplifier are present, provid-

ing maximum flexibility for the analog interface.

MC145503

The MC145503 PCM Codec–Filter is intended for stan-

dard byte interleaved synchronous or asynchronous applica-

tions. TDC can be one of five discrete frequencies. These

are 128 kHz (40 to 60% duty cycle), 1.536, 1.544, 2.048, or

2.56 MHz. (For other data clock frequencies, see MC145502

or MC145505.) The internal reference is set for 3.15 V peak

full scale, and the full scale input level at Txl and output level

at RxO is 6.3 V peak–to–peak. This is the + 3 dBm0 level of

the PCM Codec–Filter. The +Tx and –Tx inputs provide max-

imum flexibility for analog interface. All other functions are

described in the pin description.

MC145505

The MC145505 PCM Codec–Filter is intended for byte in-

terleaved synchronous applications. The MC145505 has all

the features of the MC145503 but internally connects TDC

and RDC (see pin description) to the DC pin. One of the five

standard frequencies (listed above) should be applied to

MC145500•MC145501•MC145502•MC145503•MC145505MOTOROLA

CCI. The data clock input (DC) can be any frequency be-

tween 64 kHz and 4.096 MHz.

PIN DESCRIPTIONS

DIGITAL

Logic Level Select input and TTL Digital Ground

controls the logic levels and digital ground reference

for all digital inputs and the digital output. These devices can

operate with logic levels from full supply (V

to V

) or

with TTL logic levels using V

as digital ground. For V

, all I/O is full supply (V

to V

swing) with CMOS

switch points. For V

< V

< (V

– 4 V), all inputs and

outputs are TTL compatible with V

being the digital ground.

The pins controlled by V

are inputs MSI, CCI, TDE, TDC,

RCE, RDC, RDD, PDI

, and output TDD.

MSI

Master Synchronization Input

MSI is used for determining the sample rate of the transmit

side and as a time base for selecting the internal prescale

divider for the convert clock input (CCI) pin. The MSI pin

should be tied to an 8 kHz clock which may be a frame sync

or system sync signal. MSI has no relation t o transmit or

receive data timing, except for determining the internal trans-

mit strobe as described under the TDE pin description. MSI

should be derived from the transmit timing in asynchronous

applications. In many applications MSI can be tied to TDE.

(MSI is tied internally to TDE in MC145503/05.)

CCI

Convert Clock Input

CCI is designed to accept five discrete clock frequencies.

These are 128 kHz, 1.536 MHz, 1.544 MHz, 2.048 MHz, or

2.56 MHz. The frequency at this input is compared with MSI

and prescale divided to produce the internal s equencing

clock at 128 kHz (or 16 times the sampling rate). The duty

cycle of CCI is dictated by the minimum pulse width except

for 128 kHz, which is used directly for internal sequencing

and must have a 40 to 60% duty cycle. In asynchronous

applications, CCI should be derived from transmit timing.

(CCI is tied internally to TDC in MC145500/01/03.)

TDC

Transmit Data Clock Input

TDC can be any frequency from 64 kHz to 4.096 MHz, and

is often tied to CCI if the data rate is equal to one of the five

discrete frequencies. This clock is t he shift clock for the

transmit shift register and its rising edges produce succes-

sive data bits at TDD. TDE should be derived from this clock.

(TDC and RDC are tied together internally in the MC145505

and are c alled DC.) CCI is internally tied to TDC on t he

MC145500/ 01/03. Therefore, TDC must satisfy CCI timing

requirements also.

TDE

Transmit Data Enable Input

TDE serves three major functions. The first TDE rising

edge following an MSI rising edge generates the internal

transmit strobe which initiates an A/D conversion. The inter-

nal transmit strobe also transfers a new PCM data word into

the transmit shift register (sign bit first) ready to be output at

TDD. The TDE pin is the h igh impedance control for the

transmit digital data (TDD) output. As long as this pin is high,

the TDD output stays low impedance. This pin also enables

the output shift register for clocking out the 8–bit serial PCM

word. T he logical A ND of the TDE pin with the TDC pin

clocks out a new data bit at TDD. TDE should be held high

for eight consecutive TDC cycles to clock out a complete

PCM word for byte interleaved applications. The transmit

shift register feeds back on itself to allow multiple reads of

the transmit data. If the PCM word is clocked out once per

frame in a byte interleaved system, the MSI pin function is

transparent and may be connected to TDE.

The TDE pin may be cycled during a PCM word for bit in-

terleaved applications. TDE controls both the high imped-

ance state of the TDD output and the internal shift clock. TDE

must fall before TDC rises (t

su8

) to ensure integrity of the

next data bit. There must be at least two TDC falling edges

between the last TDE rising edge of one frame and the first

TDE rising edge of the next frame. MSI must be available

separate from TDE for bit interleaved applications.

TDD

Transmit Digital Data Output

The output levels at t his pin are controlled by the V

pin. For V

connected to V

, the output levels are from

to V

. For a voltage of V

between V

– 4 V and V

the output levels are TTL compatible with V

being the digi-

tal g round supply. The TDD p in is a three–state o utput

controlled by the TDE pin. The timing of this pin is controlled

by TDC and TDE. When in TTL mode, this output may be

made high–speed CMOS compatible using a pull–up resis-

tor. The data format (Mu–Law, A–Law, or sign magnitude) is

controlled by the Mu/A pin.

RDC

Receive Data Clock Input

RDC can be any frequency from 64 kHz to 4.096 MHz.

This pin is often tied to the TDC pin for applications that can

use a common clock for both transmit and receive data trans-

fers. The receive shift register is controlled by the receive

clock enable (RCE) pin to clock data into the receive digital

data (RDD) pin on falling RDC edges. These three signals

can be asynchronous with all other digital pins. The RDC in-

put is internally tied to the TDC input on the MC145505 and

called DC.

RCE

Receive Clock Enable Input

The rising edge of RCE should identify the sign bit of a re-

ceive PCM word on RDD. The next falling edge of RDC, after

a rising RCE, loads the first bit of the PCM word into the re-

ceive register. The next seven falling edges enter the remain-

der of the PCM word. On the ninth rising edge, the receive

PCM word is transferred to the receive buffer register and the

A/D sequence is interrupted to commence the decode pro-

cess. In asynchronous applications with an 8 kHz transmit

sample rate, the receive sample rate should be between 7.5

and 8.5 kHz. Two receive PCM words may be decoded and

analog summed each transmit frame to allow on–chip con-

ferencing. The two PCM words should be clocked in as two

single PCM words, a m inimum of 31.25 µs apart, with a

receive data clock of 512 kHz or faster.

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