ML145554 ML145564
ML145557 ML145567
PCM Codec–Filter
Legacy Device: Motorola MC145554, MC145557, MC145564, MC145567
The ML145554, ML145557, ML145564, and ML145567 are all per channel
PCM Codec–Filters. These devices perform the voice digitization and recon-
struction as well as the band limiting and smoothing required for PCM sys-
tems. They are designed to operate in both synchronous and asynchronous
applications and contain an on–chip precision voltage reference. The
ML145554 (Mu–Law) and ML145557 (A–Law) are general purpose devices
that are offered in 16–pin packages. The ML145564 (Mu–Law) and
ML145567 (A–Law), offered in 20–pin packages, add the capability of analog
loopback and push–pull power amplifiers with adjustable gain.
These devices have an input operational amplifier whose output is the input
to the encoder section. The encoder section immediately low–pass filters the
analog signal with an active R–C filter to eliminate very–high–frequency noise
from being modulated down to the pass band by the switched capacitor filter.
From the active R–C filter, the analog signal is converted to a differential sig-
nal. From this point, all analog signal processing is done differentially. This
allows processing of an analog signal that is twice the amplitude allowed by a
single–ended design, which reduces the significance of noise to both the invert-
ed and non–inverted signal paths. Another advantage of this differential design
is that noise injected via the power supplies is a common–mode signal that is
cancelled when the inverted and non–inverted signals are recombined. This
dramatically improves the power supply rejection ratio.
After the differential converter, a differential switched capacitor filter band-
passes the analog signal from 200 Hz to 3400 Hz before the signal is digitized-
by the differential compressing A/D converter.
The decoder accepts PCM data and expands it using a differential D/A con-
verter. The output of the D/A is low–pass filtered at 3400 Hz and sinX/X com-
pensated by a differential switched capacitor filter. The signal is then filtered
by an active R–C filter to eliminate the out–of–band energy of the switched
capacitor filter.
These PCM Codec–Filters accept both long–frame and short–frame industry
standard clock formats. They also maintain compatibility with Motorola’s fami-
ly of TSACs and MC3419/MC34120 SLIC products.
The ML145554/57/64/67 family of PCM Codec–Filters utilizes CMOS due
to its reliable low–power performance and proven capability for complex
analog/digital VLSI functions.
P DIP 16 = EP
PLASTIC DIP
CASE 648
16
ML145554/57
1
SOG 16 = -5P
SOG PACKAGE
CASE 751G
16
1
ML145554/57
P DIP 20 = RP
PLASTIC DIP
CASE 738
20
1
ML145564/67
SOG 20 = -6P
SOG PACKAGE
CASE 751D
20
1
ML145564/67
CROSS REFERENCE/ORDERING INFORMATION
PACKAGE
MOTOROLA
LANSDALE
P DIP 16
SO 16W
P DIP 16
SO 16W
P DIP 20
SO 20W
P DIP 20
SO 20W
MC145554P
ML145554EP
MC145554DW ML145554-5P
MC145557P
MC145557DW ML145557-5P
MC145564P ML145564RP
MC145564DW ML145564-6P
MC145567P ML145567RP
MC145567DW ML145567-6P
ML145557EP
Note: Lansdale lead free (Pb) product, as it
becomes available, will be identified by a part
number prefix change from ML to MLE.
FEATURES
ML145554/57(16–Pin Package)
• Fully Differential Analog Circuit Design for Lowest Noise
• Performance Specified for Extended Temperature Range of – 40 to + 85°C
• Transmit Band–Pass and Receive Low–Pass Filters On–Chip
• Active R–C Pre–Filtering and Post–Filtering
• Mu–Law Companding ML145554
• A–Law Companding ML145557
• On–Chip Precision Voltage Reference (2.5 V)
• Typical Power Dissipation of 40 mW, Power Down of 1.0 mW at 5 V
ML145564/67(20–Pin Package) — All of the Features of the ML145554/57 Plus:
• Mu–Law Companding ML145564
• A–Law Companding ML145567
• Push–Pull Power Drivers with External Gain Adjust
• Analog Loopback
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