MT8967 Zarlink Semiconductor, Inc., MT8967 Datasheet - Page 9

• Manufacturer Part Number: MT8967
• Description: Integrated CODEC with A-Law companding and CCITT PCM encoding (20 pin PDIP-SOIC)
• Manufacturer: Zarlink Semiconductor, Inc.

Powerdown
Powerdown of the chip is achieved in several ways:
Internal Control:
1)
2)
Register Select
From ST-BUS
From ST-BUS
Master Clock
to ST-BUS
Alignment
Note: If C2i stops at a continuous logic low
(GNDD), the digital data and status is
indeterminate.
V
cycles and during this period the chip will
accept input only from C2i. The B-register is
reset to zero forcing SD0-5 to be inactive. Bits
0-5 of Register A (gain adjust bits) are forced
to zero and bits 6 and 7 of Register A become
logic high thus reinforcing the powerdown.
after C2i has assumed a continuous logic high
(V
same state as in (1) above.
Initial Power-up. Initial application of V
Loss of C2i. Powerdown is entered 10 to 40 µs
EE
DD
causes powerdown for a period of 25 clock
). In this condition the chip will be in the
5V
MT8960/61/64/65
CSTi
DSTi
C2i
DSTo
V
F1i
CA
SD3
SD2
DD
GNDD
GNDA
ANUL
V
SD0
SD1
V
Ref
V
V
EE
R
X
Figure 7 - Typical Use of the Special Drive Outputs
2.5V
-5V
ISO
0.1µF
2
-CMOS
DD
(With Relay
Ring Trip
and
Drive)
Filter
MT8960/61/62/63/64/65/66/67
External Control:
1)
2)
Register A. Powerdown is controlled by bits 6
and 7 ( when both at logic high) of Register A
which in turn receives its control word input
via CSTi, when F1i is low and CA input is
either at V
the filters and analog sections of the chip. The
analog ouput buffer at V
GNDA. DSTo becomes high impedance and
the clocks to the majority of the logic are
stopped. SD outputs are unaffected and may
be updated as normal.
CSTi Input. With CA at V
continuous logic high the chip assumes the
same state as described in External Control
(1) above.
Section
Gain
EE
Converter
2/4 Wire
or GNDD. Power is removed from
(With Relay
(With Relay
Ring Feed
Message
Waiting
R
Drive)
Drive)
will be connected to
EE
and CSTi held at
Telephone
-100V DC
-48V DC
90V
-48V DC
Line
RMS
6-27