TP3070, TP3071, TP3070-X COMBO II Programmable PCM CODEC/Filter
April 1994
TP3070, TP3071, TP3070-X
COMBO
®
II Programmable PCM CODEC/Filter
General Description
The TP3070 and TP3071 are second-generation combined
PCM CODEC and Filter devices optimized for digital switch-
ing applications on subscriber line and trunk cards. Using
advanced switched capacitor techniques, COMBO II com-
bines transmit bandpass and receive lowpass channel filters
with a companding PCM encoder and decoder. The devices
are A-law and µ-law selectable and employ a conventional
serial PCM interface capable of being clocked up to
4.096 MHz. A number of programmable functions may be
controlled via a serial control port.
Channel gains are programmable over a 25.4 dB range in
each direction, and a programmable filter is included to en-
able Hybrid Balancing to be adjusted to suit a wide range of
loop impedance conditions. Both transformer and active
SLIC interface circuits with real or complex termination im-
pedances can be balanced by this filter, with cancellation in
excess of 30 dB being readily achievable when measured
across the passband against standard test termination net-
works.
To enable COMBO II to interface to the SLIC control leads, a
number of programmable latches are included; each may be
configured as either an input or an output. The TP3070 pro-
vides 6 latches and the TP3071 5 latches.
Features
n
Complete CODEC and FILTER system including:
— Transmit and receive PCM channel filters
— µ-law or A-law companding encoder and decoder
— Receive power amplifier drives 300Ω
— 4.096 MHz serial PCM data (max)
n
Programmable Functions:
— Transmit gain: 25.4 dB range, 0.1 dB steps
— Receive gain: 25.4 dB range, 0.1 dB steps
— Hybrid balance cancellation filter
— Time-slot assignment; up to 64 slots/frame
— 2 port assignment (TP3070)
— 6 interface latches (TP3070)
— A or µ-law
— Analog loopback
— Digital loopback
n
Direct interface to solid-state SLICs
n
Simplifies transformer SLIC; single winding secondary
n
Standard serial control interface
n
80 mW operating power (typ)
n
1.5 mW standby power (typ)
n
Designed for CCITT and LSSGR applications
n
TTL and CMOS compatible digital interfaces
n
Extended temperature versions available for −40˚C to
+85˚C (TP3070V-X)
Note:
See also AN-614, COMBO II application guide.
COMBO
®
and TRI-STATE
®
are registered trademarks of National Semiconductor Corporation.
© 1999 National Semiconductor Corporation
DS008635
www.national.com
NSC [ NATIONAL SEMICONDUCTOR ]
