AGERE T7570

Data Sheet
October 1996
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Features
■
Programmable internal hybrid-balance network
■
Programmable transmit gain
— 19.4 dB range, 0.1 dB step size
■
Programmable receive gain
— 19.4 dB range, 0.1 dB step size
■
Dual-programmable PCM interface
— Up to 64 time slots per frame
— Variable data rate (64 kHz to 4.096 MHz)
— Two timing modes
■
Programmable µ-law or A-law companding
■
300 Ω drive receive amplifier
■
Analog and digital loopbacks
■
On-chip sample-and-hold, autozero, and precision
voltage reference
■
Single 5 V power supply
■
Latch-up free, low-power CMOS technology
— 70 mW typical operating power dissipation
— 1.5 mW typical standby power dissipation
■
Serial microprocessor-control interface
■
6-pin parallel I/O latch
■
TTL- and CMOS-compatible digital I/O
■
Meets or exceeds D3/D4 (as per Lucent PUB
43801), ITU-T (formerly CCITT) G.711—G.714,
and LSSGR requirements
■
Operating temperature range: –40 °C to +85 °C
Description
The Lucent Technologies Microelectronics Group
T7570 Programmable PCM Codec with Hybrid-Balance Filter is a programmable PCM codec with an
internal hybrid-balance network filter. It provides analog-to-digital and digital-to-analog conversion, as well
as the transmit and receive filtering necessary to
interface a voice telephone circuit to a time-division
multiplexed (TDM) system. Programmable features
include transmit gain setting over a 19.4 dB range
and receive gain setting over a 19.4 dB range. An
internal filter can be programmed to provide hybrid
balancing over a wide range of loop impedances for
both active and transformer subscriber line interface
circuits (SLIC).
The device is programmed over a low pin-count,
standard, serial, microprocessor-control interface. A
6-pin parallel input/output latch is provided to control
interface circuits. Each of these pins can be individually programmed to be an input or an output.
The T7570 is fabricated by using a low-power CMOS
technology, requires a single 5 V supply, and is available in a 28-pin PLCC package for surface mounting.
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Data Sheet
October 1996
Table of Contents
Content
Page
Features ................................................................................................................................................................... 1
Description ............................................................................................................................................................... 1
Pin Information ......................................................................................................................................................... 3
Functional Description .............................................................................................................................................. 5
Powerup Initialization ............................................................................................................................................ 5
Powerdown State .................................................................................................................................................. 5
Transmit Filter and Encoder .................................................................................................................................. 5
Decoder and Receive Filter .................................................................................................................................. 6
PCM Interface ....................................................................................................................................................... 6
Serial Control Port ................................................................................................................................................ 6
Programmable Functions ...................................................................................................................................... 7
Hybrid-Balance Filter .......................................................................................................................................... 11
Programming the Filter ....................................................................................................................................... 12
Absolute Maximum Ratings .................................................................................................................................... 13
Handling Precautions ............................................................................................................................................. 13
Electrical Characteristics ........................................................................................................................................ 14
dc Characteristics ............................................................................................................................................... 14
Transmission Characteristics .................................................................................................................................. 15
Timing Characteristics ............................................................................................................................................ 20
Applications ............................................................................................................................................................ 25
Outline Diagrams .................................................................................................................................................... 26
28-Pin PLCC ....................................................................................................................................................... 26
Ordering Information ............................................................................................................................................... 27
2
Lucent Technologies Inc.
Data Sheet
October 1996
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Description (continued)
AZ
VFX I
TRANSMIT
FILTER
ENCODER
TX REGISTER
DIGITAL
LOOPBACK
HYBRID
BALANCE
FILTER
TIME-SLOT
ASSIGNMENT
V REF
ANALOG
LOOPBACK
RX REGISTER
RECEIVE
FILTER
VFRO
DECODER
DX0
DX1
TSX0
TSX1
FSX
BCLK
FSR
DR0
DR1
MCLK
MR
IL5
CONTROL
REGISTER
IL4
IL3
IL2
INTERFACE
LATCHES
CS
CCLK
CO
CI
IL1
IL0
5-2786 (C)
Figure 1. Block Diagram
IL0
26
VFXI
28
VDD
GND
1
27
VFRO
2
NC
3
4
NC
Pin Information
NC
5
25
IL1
IL3
6
24
IL4
IL2
7
23
IL5
FSR
8
22
FSX
DR1
9
21
TSX1
DR 0
10
20
TSX0
CO
11
19
DX1
12
13
14
15
16
17
18
CI
CCLK
CS
MR
BCLK
MCLK
DX0
T7570 --- ML2
5-2787 (C)
Figure 2. Pin Diagram
Lucent Technologies Inc.
3
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Data Sheet
October 1996
Pin Information (continued)
Table 1. Pin Description
4
Pin
1
2
Symbol
GND
VFRO
Type
—
O
3
4
5
6
7
NC
NC
—
—
IL3
IL2
I/O
I/O
8
FSR
I
9
10
DR 1
DR0
I
I
11
CO
O
12
CI
I
13
CCLK
I
14
CS
I
15
MR
I
16
BCLK
I
17
MCLK
I
18
19
DX0
DX1
O
O
20
21
TS X0
TS X1
O
O
Name/Description
Ground. All analog and digital signals are referenced to this pin.
Receive Analog Power Amplifier Output. This pin can drive load impedances as low
as 300 Ω . PCM data received on the assigned DR pin is decoded and appears at this
output as a voice-frequency signal.
No Connect. Connections may be made to or traces may be routed through this pin.
No Connects. Do not make connections to or route traces through pins 4 and 5.
Interface Latch I/O. These pins can be individually programmed as inputs or outputs
as determined by the state of the corresponding bits in the latch direction register
(LDR). For pins configured as inputs, the logic state sensed on each input is latched
into the interface latch register (ILR) whenever control data is written to the T7570, and
the information is shifted out on the CO pin. When configured as outputs, control data
written into the ILR appears at the corresponding IL pins.
Receive Frame-Sync Input. A pulse or square-wave waveform with an 8 kHz repetition rate is applied to this input to define the start of the receive time slot assigned to
this device (nondelayed frame mode), or the start of the receive frame (delayed frame
mode using the internal time-slot assignment counter).
Receive PCM Inputs. These receive data input(s) are inactive except during the
assigned receive time slot of the assigned port when the receive PCM data is shifted in
on the falling edges of BCLK.
Control Output. Serial control information is shifted out from the T7570 on this pin
when CS is low. It can be connected to CI if required.
Control Input. Serial control information is shifted into the T7570 on this pin when CS
is low. It can be connected to CO if required.
Control Clock. This clock shifts serial control information into CI or out from CO when
the CS is low, depending on the current instruction. CCLK can be asynchronous with
the other system clocks.
Chip Select (Active-Low). When this pin is low, control information can be written into
or read from the T7570 via the CI and CO pins.
Master Reset. This logic input must be pulled low for normal operation of the T7570.
When pulled momentarily high (at least 1 µs), all programmable registers in the device
are reset to the states specified under powerup initialization.
Bit Clock Input. This pin shifts PCM data into and out of the DR and DX pins. BCLK
can vary from 64 kHz to 4.096 MHz in 8 kHz increments and must be synchronous with
MCLK at the start of each frame. MCLK can be used as BCLK.
Master Clock. The master-clock input is used by the switched capacitor filters and the
encoder and decoder sequencing logic. It must be 1.536 MHz, 1.544 MHz,
2.048 MHz, or 4.096 MHz and must be synchronous with BCLK at the start of each
frame.
Transmit PCM Output. These transmit-data, high-impedance state outputs remain in
the high-impedance state except during the assigned transmit time slot on the
assigned port, during which the transmit PCM data byte is shifted out on the rising
edges of BCLK.
Backplane Line Driver Enable (Active-Low). Normally, these open-drain outputs are
floating in a high-impedance state. When a time slot is active on one of the DX outputs,
the appropriate TS X output pulls low to enable a backplane line driver.
Lucent Technologies Inc.
Data Sheet
October 1996
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Pin Information (continued)
Table 1. Pin Description (continued)
Pin
22
Symbol
FSX
Type
I
23
24
25
26
27
28
IL5
IL4
IL1
IL0
VDD
VFXI
I/O
I/O
I/O
I/O
—
I
Name/Description
Transmit Frame-Sync Input. A pulse or square-wave waveform
with an 8 kHz repetition rate is applied to this input to define the start
of the transmit time slot assigned to this device (nondelayed frame
mode) or the start of the transmit frame (delayed frame mode using
the internal time-slot assignment counter). If only the receive channel is being used, it is still necessary to apply the transmit framesync every frame.
Interface Latch. See pin 6.
5 V ± 5% Power Supply.
Transmit Analog High-Impedance Input. Voice-frequency signals
present on this input are encoded as an A-law or µ-law PCM bit
stream and are shifted out on the selected DX pin.
Functional Description
control instructions into the serial control port with the
P bit set to 1, as indicated in Table 2.
Powerup Initialization
The powerdown instruction can be included within any
other instruction code. It is recommended that the chip
be powered down before executing any instructions. In
the powerdown state, all nonessential circuitry is deactivated and the DX0 and DX1 outputs are in the highimpedance condition.
When power is first applied, powerup reset circuitry initializes the T7570 and puts it into the powerdown state.
The gain control registers for the transmit and receive
gain sections are programmed to off, the hybridbalance circuit is turned off, the power amp is disabled,
and the device is in the nondelayed timing mode. The
latch direction register (LDR) is preset with all IL pins
programmed as inputs, placing the interface pins in a
high-impedance state. The CI is ready for the first control byte of the initialization sequence. Other initial
states in the control register are indicated in the Control
Register Instruction section under Programmable
Functions.
A reset to these same initial conditions can also be
forced by driving the MR pin momentarily high for at
least 1 µs. This can be done either on powerup or powerdown. For normal operation, this pin must be pulled
low.
The desired modes for all programmable functions can
be initialized via the serial control port prior to a powerup command.
Powerdown State
Following a period of activity in the powerup state, the
powerdown state can be entered by writing any of the
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The coefficients stored in the hybrid-balance circuit and
the gain control registers, the data in the LDR and ILR,
and all control bits remain unchanged in the powerdown state unless changed by writing new data via the
serial control port, which remains active. The outputs of
the interface latches also remain active, maintaining
the ability to monitor and control interface circuits like a
SLIC.
Transmit Filter and Encoder
The transmit section input, VFXI, provides a highimpedance load to the line-interface circuit. The input
signal is summed with the internal hybrid cancellation
signal. The resulting signal is the input to a programmable gain or attenuation amplifier that is controlled by the
contents of the transmit gain register (see Programmable Functions section). The signal is then passed
through an antialiasing filter followed by a fifth-order,
low-pass and third-order, high-pass, switched-capacitor
filter. After the filter, the A/D converter translates
the signal into PCM data for transmission. The A/D
5
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Functional Description (continued)
Transmit Filter and Encoder (continued)
converter has a compressing characteristic according
to the standard ITU-T A- or µ-coding laws selected by a
control instruction (see Tables 2 and 3). A precision onchip voltage reference helps ensure accurate and
highly stable transmission levels. Any offset voltage
arising in the gain-set amplifier, the filters, or the comparator is canceled by an internal autozero circuit.
Data Sheet
October 1996
mit time slot, the selected DX0/1 output shifts data out
from the PCM register on the rising edges of BCLK.
TS X0 (or TS X1 as appropriate) also pulls low for the
first 7.5 bit times of the time slot to control the highimpedance state enable of a backplane line driver.
Serial PCM data is shifted into the selected DR0/1 input
during each assigned receive time slot on the falling
edges of BCLK. DX0 or DX1 and DR0 or DR1 are selectable on the T7570 (see the Port Selection section
under Programmable Functions).
Serial Control Port
Decoder and Receive Filter
PCM data is shifted into the decoder's receive PCM
register via the DR0 or DR1 pin during the selected time
slot on eight falling edges of BCLK. The decoder consists of an expanding digital-to-analog convertor with
either A- or µ-law decoding characteristic, which is
selected by the same control instruction used to select
the encode law. Following the decoder is a fifth-order,
low-pass, switched-capacitor filter with Sin(x)/x correction for the 8 kHz sample and hold. A programmable
gain amplifier that is set by writing to the receive gain
register is included, followed by a power amplifier capable of driving a 300 Ω load to 4.0 V peak to peak.
PCM Interface
The FSX and FSR frame-sync inputs determine the
beginning of the 8-bit transmit and receive time slots,
respectively. They can have any duration from a single
cycle of BCLK high to one MCLK period low. Two different relationships can be established between the
frame-sync inputs and the actual time slots on the PCM
buses by setting bit 3 in the control register (see
Table 3). Nondelayed data mode is similar to longframe timing of other codecs for which time slots begin
nominally coincident with the rising edge of the appropriate FS input. The alternative is to use delayed-data
mode in which each FS input must be high at least a
half-cycle of BCLK earlier than the time slot. The timeslot assignment circuit on the device can only be used
with delayed-data timing.
Programmable register instructions (Table 2) are written into or read back from the T7570 via the serial control port consisting of the control clock (CCLK), the
serial data input (CI) and output (CO), and the chipselect input ( CS ) (see Figure 6). All instructions
require 2 bytes, with the exception of a single-byte
powerup/powerdown command. The bits in byte 1 are
defined as follows: bit 7 specifies powerup or powerdown; bits 6, 5, 4, and 3 specify the register address;
bit 2 specifies whether the instruction is a read or a
write; bit 1 specifies a one- or two-byte instruction; and
bit 0 is not used.
To shift control data into the T7570, CCLK must be
pulsed high eight times while CS is low. Data on the CI
input is shifted into the serial input register on the falling edge of each CCLK pulse. After all data is shifted
in, the contents of the input shift register are decoded
and can indicate that a second byte of control data
follows. This second byte can either be defined by a
second byte wide CS pulse or can follow the first contiguously; it is not mandatory for CS to return high
between the first and second control bytes.
At the end of the eighth CCLK pulse in the second control byte, the data is loaded into the appropriate programmable register. CS can remain low continuously
when programming successive registers, if desired.
However, CS should be set high when no data transfers are in progress.
The time-slot assignment capability of this device is a
subset of the Lucent concentration highway interface.
The beginning of the first time slot in a frame is identified by the appropriate FS input. The actual transmit
and receive time slots are then determined by the internal time-slot assignment counters.
To read back interface latch data or status information
from the T7570, the first byte of the appropriate instruction, as defined in Table 2, is strobed in during the first
CS pulse. CS must then be taken low for a further
eight CCLK cycles, during which the data is shifted
onto the CO pin on the rising edges of CCLK. When
CS is high, the CO pin is in the high-impedance state,
enabling the CO pins of many devices to be multiplexed
together.
Transmit and receive frames and time slots can be
skewed from each other by any number of BCLK cycles
by offsetting FSR and FSX. During each assigned trans6
Lucent Technologies Inc.
Data Sheet
October 1996
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Functional Description (continued)
included with the last programming instruction or in a
separate single-byte instruction. When the powerup or
powerdown control is entered as a single-byte instruction, bit 1 must be 0.
Programmable Functions
Any of the programmable registers can be modified
while the device is powered up or down.
When a powerup command is given, all deactivated
circuits are activated, but the PCM outputs, DX0 and
DX1, remain in the high-impedance state until the second FSX pulse after powerup.
Powerup/Powerdown Control
Following powerup initialization, powerup and powerdown control can be accomplished by writing any of the
control instructions listed in Table 2 into the T7570, with
the P bit set to 0 for powerup or 1 for powerdown. Normally, it is recommended that all programmable functions be initially programmed while the device is
powered down. Power-state control can then be
Control Register Instruction
The first byte of a read or write instruction to the control
register is as shown in Table 2. The second byte has
the bit functions shown in Tables 3, 5, 6, 7, 8, and 9.
Table 2. Programmable Register Instructions
Function
Byte 1
Address
PDN
Byte 2
R/W
P2
X
Single-byte Powerup/Powerdown
Write Control Register
Read Control Register
Write Interface Latch Register
Read Interface Latch Register
Write Latch Direction Register
Read Latch Direction Register
Write Receive Gain Register
Read Receive Gain Register
Write Transmit Gain Register
Read Transmit Gain Register
Write Hybrid-balance Register 1
Read Hybrid-balance Register 1
Write Hybrid-balance Register 2
Read Hybrid-balance Register 2
Write Hybrid-balance Register 3
Read Hybrid-balance Register 3
7
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
6
X
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
5
X
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
4
X
0
0
0
0
1
1
0
0
0
0
1
1
1
1
0
0
3
X
0
0
1
1
0
0
0
0
1
1
0
0
1
1
0
0
2
X
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Write Receive Time Slot/Port
Read Receive Time Slot/Port
Write Transmit Time Slot/Port
Read Transmit Time Slot/Port
P
P
P
P
1
1
1
1
0
0
0
0
0
0
1
1
1
1
0
0
0
1
0
1
1
1
1
1
X
X
X
X
DATA
None
See Table 3.
See Table 6.
See Table 5.
See Table 9.
See Table 8.
These bits are defined by
the Lucent T7570 hybridbalance software program. Contact your
Lucent-ME Account Representative for a copy of
this software.
See Table 7.
(receive instruction)
See Table 7.
(transmit instruction)
Notes:
Bit 7 of bytes 1 and 2 is always the first bit clocked into or out from the CI and CO pins. X = don't care.
P is the powerup/down control bit (0 = powerup, 1 = powerdown); see Powerup/Powerdown Control section.
Other register address codes are invalid and should not be used.
Lucent Technologies Inc.
7
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Data Sheet
October 1996
Functional Description (continued)
Programmable Functions (continued)
Control Register Instruction (continued)
Table 3. Control Register Byte 2 Functions
7
F1
0
0
1
1
—
—
—
—
—
—
—
—
—
—
6
F0
0
1
0
1
—
—
—
—
—
—
—
—
—
—
Bit Number and Name
5
4
3
2
MA
IA
DN DL
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
0
X
—
—
1
0
—
—
1
1
—
—
—
—
0
—
—
—
1
—
—
—
—
0
—
—
—
1
—
—
—
0
—
—
—
—
—
—
—
—
1
AL
—
—
—
—
—
—
—
—
—
0
X
1
—
—
0
PP
—
—
—
—
—
—
—
—
—
—
—
—
0
1
Function
Reserved
MCLK = 1.536 MHz or 1.544 MHz
MCLK = 2.048 MHz*
MCLK = 4.096 MHz
µ-law*
A-law, Including Even Bit Inversion
A-law, No Even Bit Inversion
Delayed Data Timing
Nondelayed Data Timing*
Normal Operation*
Digital Loopback
Analog Loopback
Power Amp Enabled in Powerdown
Power Amp Disabled in Powerdown*
* State at powerup initialization (bit 4 = 0).
Table 4. Coding Law Conventions
VIN
VIN = + Full Scale
VIN = 0 V
VIN = – Full Scale
µ-Law
MSB LSB
10000000
11111111
00000000
True A-Law With
Even Bit Inversion
MSB LSB
10101010
11010101
00101010
A-Law Without
Even Bit Inversion
MSB LSB
111111111
10000000
01111111
Note: The MSB is always the first PCM bit shifted in or out of the T7570.
Master Clock Frequency Selection
Analog Loopback
A master clock must be provided to the T7570 for operation of the filter and coding/decoding functions. The
MCLK frequency must be either 1.536 MHz,
1.544 MHz, 2.048 MHz, or 4.096 MHz and must be
synchronous with BCLK at the start of each frame. Bits
F0 and F1 (see Table 3) must be set during initialization
to select the correct internal divider.
The analog loopback mode is entered by setting the AL
and DL bits in the control register as shown in Table 3.
In the analog loopback mode, the transmit input VFXI is
isolated from the input pin and internally connected to
the VFRO output, forming a loop from the receive PCM
register back to the transmit PCM register. The VFRO
pin remains active, and the programmed settings of the
transmit and receive gains remain unchanged; therefore, care must be taken to ensure that overload levels
are not exceeded anywhere in the loop. It is recommended that the hybrid-balance filter be disabled during analog loopback.
Coding Law Selection
Bits MA and IA in Table 3 permit the selection of µ-law
coding or A-law coding, with or without even bit inversion.
8
Lucent Technologies Inc.
Data Sheet
October 1996
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Functional Description (continued)
Programmable Functions (continued)
It is recommended that during initialization, the state of
IL pins to be configured as outputs should be programmed first, followed immediately by the LDR.
Digital Loopback
Table 6. Interface Latch Data Bit Order Bit Number
The digital loopback mode is entered by setting the AL
and DL bits in the control register as shown in Table 3.
This mode provides another stage of path verification
by enabling data written into the receive PCM register
to be read back from that register in any transmit time
slot at DX0/1. In digital loopback mode, the decoder
remains functional and outputs a signal at VFRO. If this
is undesirable, the receive output can be disabled by
programming the receive gain register to all 0s.
Interface Latch Directions
Immediately following powerup, all interface latches
assume they are inputs and, therefore, all IL pins are in
a high-impedance state. Each IL pin can be individually
programmed as a logic input or output by writing the
appropriate instruction to the LDR (see Tables 2 and 5).
For minimum power dissipation, unconnected latch
pins should be programmed as outputs.
Bits L5—L0 must be set by writing the specified instruction to the LDR with the L bits in the second byte set as
follows.
Table 5. Byte 2 Functions of Latch Direction
Register
7
L0
6
L1
Byte 2 Bit Number
5
4
3
2
L2
L3
L4
L5
1
X
0
X
Note: X = don't care.
Ln Bit
0
1
IL Direction
Input
Output
Interface Latch States
Interface latches configured as outputs assume the
state determined by the appropriate data bit in the
2-byte instruction written to the interface latch register
(ILR) as shown in Tables 2 and 6. Latches configured
as inputs sense the state applied by an external
source, such as the off-hook detect output of a SLIC.
All bits of the ILR, i.e., sensed inputs and the programmed state of outputs, can be read back in the second byte of a read of the ILR.
Lucent Technologies Inc.
7
D0
6
D1
5
D2
Bit Number
4
3
D3
D4
2
D5
1
X
0
X
Time-Slot Assignment
The T7570 can operate in either fixed time-slot or timeslot assignment mode for selecting the transmit and
receive PCM time slots. Following powerup, the device
is automatically in nondelayed timing mode, in which
the time slot always begins with the leading (rising)
edge of frame-sync inputs FSX and FSR. Time-slot
assignment can only be used with delayed-data timing
(see Figure 5). FSX and FSR can have any phase relationship with each other in BCLK period increments.
Alternatively, the internal time-slot assignment counters
and comparators can be used to access any time slot
in a frame by using the frame-sync inputs as marker
pulses for the beginning of transmit and receive time
slots of 8 bits each. A time slot is assigned by a 2-byte
instruction as shown in Tables 2 and 7. The last 6 bits
of the second byte indicate the selected time slot from
0 to 63 using straight binary notation. A new assignment becomes active on the second frame following
the end of the CS for the second control byte. The EN
bit allows the PCM inputs, DR0/1, or outputs, DX0/1, as
appropriate, to be enabled or disabled. Time-slot
assignment mode requires that the FSX and FSR pulses
must conform to the delayed-data timing format shown
in Figure 5.
Port Selection
Two transmit serial PCM ports, DX0 and DX1, and two
receive serial PCM ports, DR0 and DR1, are provided to
enable two-way space switching to be implemented.
Port selections for transmit and receive are made
within the appropriate time-slot assignment instruction
using the PS bit in the second byte. Port selection can
only be used in delayed-data timing mode.
Table 7 shows the format of the second byte of both
transmit and receive time-slot and port assignment
instructions.
9
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Data Sheet
October 1996
Functional Description (continued)
Programmable Functions (continued)
Table 7. Time-Slot and Port Assignment Instruction
7
EN
0
6
PS
0
0
1
1
0
1
1
Bit Number and Name
5
4
3
2
T5*
T4
T3
T2
X
X
X
X
1
T1
X
0
T0
X
Function
Disable DX0 Output (transmit instruction)
Disable DR0 Input (receive instruction)
X
X
X
X
X
X
Disable DX1 Output (transmit instruction)
Disable DR1 Input (receive instruction)
Assign One Binary-coded Time Slot from 0—63 Enable DX0 Output (transmit instruction)
Enable DR0 Input (receive instruction)
Assign One Binary-coded Time Slot from 0—63 Enable DX1 Output (transmit instruction)
Enable DR1 Input (receive instruction)
* T5 is the MSB of the time-slot assignment.
Transmit Gain Instruction Byte 2
The transmit gain can be programmed in 0.1 dB steps
from –0.4 dB to +19.0 dB by writing to the transmit gain
register as defined in Tables 2 and 8. This corresponds
to a range of 0 dBm0 levels at VFXI between
0.811 Vrms and 0.087 Vrms (equivalent to +0.4 dBm to
–19.0 dBm into 600 Ω).
To set transmit gain, determine the gain required of the
codec in order to achieve the overall desired transmission level point (TLP) at the PCM interface (usually
0 dBm or –2 dBm).
In order for the internal hybrid-balance circuitry to be
effective, the portion of VFRO returned to the codec
analog input must be between –2.5 dB to –10.25 dB of
the VFRO output. For instance, if a SLIC presents a
–6 dBm signal to VFXI when VFRO produces 0 dBm,
good hybrid balance can be achieved. If the returned
signal requires amplification to satisfy this requirement,
then an additional op amp in the transmit path would be
required. The T7570 will accommodate the phase
inversion. A spare op amp is provided in some Lucent
SLICs.
Once the codec gain is chosen, determine what signal
level at VFXI would provide the desired TLP output at
Dx. For our example of +6 dB gain (Gx) providing a
0 dBm TLP and working backwards from Dx, take the
antilog of minus 6 dB divided by 20 and multiply by the
0.7746 reference level to obtain the signal level at VFXI
in Vrms. As follows:
(1)
10
antilog10 (–Gx / 20) * 0.7746 = Vrms
Finally, convert the signal level to a decimal number (n)
using the following formula:
(2)
200 * log10 (Vrms / 0.08592) = n
Round n to the nearest integer and convert to binary.
This is the code required by byte 2 of this instruction.
Some examples are given in Table 8.
Table 8. Byte 2 of Transmit Gain Instructions
Bit Number
76543210
00000000
00000001
00000010
—
1 0 1 1 1 1 1 1*
—
11000010
1 1 0 0 0 0 1 1†
0 dBm0 Test Level (Vrms)
at VFXI
No Output
0.087
0.088
—
0.7746
—
0.802
0.811
* 0 dB path gain setting.
†Programming values greater than those listed in this table are
permitted. However, large signals may cause overload.
Receive Gain Instruction Byte 2
The receive gain can be programmed in 0.1 dB steps
from –17.3 dB to +2.1 dB by writing to the receive gain
register as defined in Tables 2 and 9. This corresponds
to a range of 0 dBm0 levels at VFRO between
0.987 Vrms and 0.106 Vrms (equivalent to +2.1 dBm to
–17.3 dBm into 600 Ω).
Lucent Technologies Inc.
Data Sheet
October 1996
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Functional Description (continued)
Programmable Functions (continued)
To set receive gain, first determine the gain required of
the codec. For line card use, determine the codec’s
allocation to set the overall transmission level point
(TLP) at Tip\Ring accordingly (usually 0 dBm or
–4 dBm).
Once the codec gain is chosen, determine the signal
level that would be delivered to VFRO when the reference TLP appears at DR. Take the antilog of the gain in
dB (GR) divided by 20 and multiply by the 0.7746 reference level to obtain the signal level at VFRO in Vrms. As
follows:
(3)
antilog10 (GR / 20) * 0.7746 = Vrms
Finally, convert the signal level output to a decimal
number (n) using the following formula:
(4)
200 * log10 (Vrms / 0.1045) = n
Round n to the nearest integer and convert to binary.
This is the code required by byte 2 of this instruction.
Some examples are given in Table 9.
Table 9. Byte 2 of Receive Gain Instructions
Bit Number
76543210
00000000
00000001
00000010
—
1 0 1 0 1 1 1 0*
—
11000010
1 1 0 0 0 0 1 1†
0 dBm0 Test Level (Vrms)
at VFRI
No Output (low Z to GND)
0.106
0.107
—
0.7746
—
0.975
0.987
* 0 dB path gain setting.
†Programming values greater than those listed in this table are
permitted. However, large signals may cause overload.
low-frequency signals across a transformer SLIC, and
the first-order section is intended to balance midrange
to higher audio-frequency signals.
As a second-order section, Hybal1 has a pair of lowfrequency zeros and a pair of complex conjugate
poles. When configuring the Hybal1, matching the
phase of the hybrid at low- to midband frequencies is
most critical. Once the echo path is correctly balanced
in phase, the magnitude of the cancellation signal can
be corrected by the programmable attenuator.
The second-order mode of Hybal1 is most suitable for
balancing interfaces with transformers having high
inductance of 1.5 H or more. An alternative configuration for smaller transformers is available by converting
Hybal1 to a simple first-order section with a single real
low-frequency pole and zero. In this mode, the
pole/zero frequency can be programmed.
Many line interfaces can be adequately balanced by
use of the Hybal1 filter only, in which case the Hybal2
filter should be deselected to bypass it.
Hybal2, the higher-frequency first-order section, is provided for balancing an electronic SLIC and is also helpful with a transformer SLIC in providing additional
phase correction for mid- and high-band frequencies,
typically 1 kHz to 3.4 kHz. Such a correction is particularly useful if the test balance impedance includes a
capacitor of 100 nF or less, such as the loaded and
nonloaded loop test networks in the United States.
Independent placement of the pole and zero location is
provided.
Figure 3 shows a simplified diagram of the local echopath for a typical application with a transformer interface. The magnitude and phase of the local echo signal, measured at VFXI, are a function of the termination
impedance ZT, the line transformer, and the impedance
of the two-wire loop, ZL. If the impedance reflected
back into the transformer primary is expressed as ZL',
then the echo path transfer function from VFRO to VFXI
is the following:
(5)
Hybrid-Balance Filter
The hybrid-balance filter on the T7570 is a programmable filter consisting of a second-order section, Hybal1,
followed by a first-order section, Hybal2, and a programmable attenuator. Either of the filter sections can
be bypassed if only one is required to achieve good
cancellation. A selectable 180° inverting stage is
included to compensate for interface circuits that invert
the transmit input relative to the receive output signal.
The second-order section is intended mainly to balance
Lucent Technologies Inc.
H(W) = ZL' /(ZT + ZL')
The signal level returned at VFXI must be between
–2.5 dB to –10.25 dB over the voice band, relative to
the output at VFRO, in order for the hybrid balance
function to be effective. Signals outside this range
exceed the range of programmability of the hybrid
path, and the software will provide unacceptable hybrid
balance performance over the voice band.
11
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Data Sheet
October 1996
Functional Description (continued)
Hybrid-Balance Filter (continued)
VFXI
TIP
–
+
RVFXI
TO TX
GAIN BLOCK
SEL
ZL'
SEL 2
HYBAL2
1ST-ORDER
HI FREQ.
FILTER
(REG 3)
ZL
2.4
RING
±1
ZT
INV
VFRO
SET IN REG 2
HYBAL1
1ST- OR
2ND-ORDER
FILTER
(REG 2)
ATTENUATOR
GAIN
+2.4
FROM RX
GAIN BLOCK
5-2788 (C)
Figure 3. Block Diagram Hybrid-Balance Filter Network
Programming the Filter
On initial powerup, the hybrid-balance filter is disabled.
Before the hybrid-balance filter can be programmed, it
is necessary to design the transformer and termination
impedance to meet system 2-wire input return loss
specifications, which are normally measured against a
fixed test impedance (600 Ω or 900 Ω in most countries). Only then can the echo path be modeled and the
hybrid-balance filter programmed. Hybrid balancing is
also measured against a fixed test impedance, specified by each national telecommunication administration
to provide adequate control of talker and listener echo
over the majority of their network connections. This test
impedance is ZL in Figure 3. The echo signal and the
degree of transhybrid loss obtained by the programmable filter must be measured from the PCM digital input,
DR0/1, to the PCM digital output, DX0/1, either by digital
test signal analysis or by conversion back to analog by
a PCM codec/filter.
7
6
SEL INV
Byte 2 of Register 1
5
4
3
2
1
0
SEL2
GAIN (All “0” = MAX)
Register 2: Select/deselect Hybal1 filter;
set Hybal1 to biquad or first order;
select pole and zero frequency.
Register 3: Program pole frequency in Hybal2 filter;
program zero frequency in Hybal2 filter.
Standard filter design techniques can be used to model
the echo path (see Equation 5) and design a matching
hybrid-balance filter configuration. Alternatively, the frequency response of the echo path can be measured
and the hybrid-balance filter designed to replicate it.
T7570 hybrid-balance software is available from your
Lucent Account Representative to aid in selecting the
best balance filter register settings.
Three registers must be programmed in the T7570 to
fully configure the hybrid-balance filter (refer to Table 2
for Byte 1 addressing):
Register 1: Select/deselect hybrid-balance filter;
invert/noninvert cancellation signal;
select/deselect Hybal2 filter section;
set attenuator.
12
Lucent Technologies Inc.
Data Sheet
October 1996
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Functional Description (continued)
Hybrid-Balance Filter (continued)
Power Supply
While the pins of the T7570 devices are well protected against electrical misuse, it is recommended that the standard CMOS practice of applying GND to the device before any other connections are made should always be followed. In applications where the printed-circuit card can be plugged into a hot socket with power and clocks
already present, an extra-long ground pin on the connector should be used.
To minimize noise sources, all ground connections to each device should meet at a common point as close as possible to the device GND pin to prevent the interaction of ground return currents flowing through a common-bus
impedance. A power-supply decoupling capacitor of 0.1 µF should be connected from this common point to VDD, as
close to the device pins as possible. The power supply should also be decoupled with a low, effective series resistance capacitor of at least 10 µF, located near the card edge connector.
Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are absolute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess
of those given in the operational sections of this data sheet. Exposure to absolute maximum ratings for extended
periods can adversely affect device reliability.
Parameter
Storage Temperature Range
Power Supply Voltage
Voltage on Any Pin with Respect to Ground
Maximum Power Dissipation (package limit)
Symbol
Tstg
VDD
—
PDISS
Min
–55
—
–0.5
—
Max
150
6.5
0.5 + VDD
600
Unit
°C
V
V
mW
Handling Precautions
Although protection circuitry has been designed into this device, proper precautions should be taken to avoid exposure to electrostatic discharge (ESD) during handling and mounting. Lucent employs a human-body model (HBM)
and a charged-device model (CDM) for ESD susceptibility testing and protection design evaluation. ESD voltage
thresholds are dependent on the circuit parameters used to define the model. No industry-wide standard has been
adopted for CDM. However, a standard HBM (resistance = 1500 Ω, capacitance = 100 pF) is widely used and
therefore can be used for comparison purposes. The HBM ESD threshold presented here was obtained using
these circuit parameters.
Table 10. Human-Body Model ESD Threshold
Device
T7570
Lucent Technologies Inc.
Voltage
≥2000 V
13
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Data Sheet
October 1996
Electrical Characteristics
For all tests, TA = –40 °C to +85 °C, VDD = 5 V ± 5%, and GND = 0 V, unless otherwise noted. Typical values are for
TA = 25 °C and nominal supply values.
dc Characteristics
Table 11. Digital Interface
Parameter
Input Voltage
Low
High
Output Voltage
Low
High
Input Current
Symbol
Test Conditions
VIL
All digital inputs
VIH
All digital inputs
VOL
DX0, DX1, CO, IL = 3.2 mA
All other digital outputs, IL = –1 mA
VOH
DX0, DX1, CO, IL = 3.2 mA
Low
High
Output Current
in Highimpedance
State
IIL
IIH
IOZ
All other digital outputs except TS X,
IL = –1 mA
All digital outputs, IL = –100 µA
Any digital input, GND < VIN < VIL
Any digital input except MR,
VIH < VIN < VCC
MR only
DX0, DX1, CO,
IL5—IL0 when selected as inputs,
GND < VOUT < VCC
TA (°C)
—
—
—
—
—
—
Min
—
2.0
—
—
2.4
2.4
Max
0.7
—
0.4
0.4
—
—
Unit
V
V
V
V
V
V
—
—
—
VCC – 0.5
–10
–10
—
10
10
V
µA
µA
—
–40 to 0
0 to 85
–10
–30
–10
100
30
10
µA
µA
µA
Typ
0.3
Max
0.9
Unit
mA
14.0
20.0
mA
4.0
6.0
mA
Table 12. Power Dissipation
Parameter
Powerdown Current
Powerup Current
Powerdown Current
14
Symbol
Test Conditions
IDD0
CCLK, CI, CO = 0.4 V, CS = 2.4 V, interface latches
set as outputs with no load, all other inputs active,
power amp disabled
IDD1
CCLK, CI, CO = 0.4 V, CS = 2.4 V, no load on power
amp, interface latches set as outputs with no load
IDD2
CCLK, CI, CO = 0.4 V, CS = 2.4 V, interface latches
set as outputs with no load, all other inputs active,
power amp disabled, no load on power amp
Lucent Technologies Inc.
Data Sheet
October 1996
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Transmission Characteristics
Table 13. Analog Interface
Parameter
Input Resistance
Input Offset Voltage at VFXI
Load Resistance
Load Capacitance
Symbol
RVFXI
VOSX
RLVFRO
CLVFRO
Output Resistance
Output Offset Voltage
at VFRO
Output Offset Voltage at
VFRO, Powerdown
Output Voltage Swing
ROVFRO
VOSR
VOSRPD
VSWR
Test Conditions
0.25 V < VFXI < 4.75 V
—
—
RLVFRO ≥ 300 Ω
CLVFRO from VFRO to GND
Steady zero PCM code applied to DR0 or DR1
Alternating ± zero PCM code applied to DR0
or DR1, maximum receive gain
Control register byte 2, bit 7 = 0
Min Typ Max
390 585 —
2.3 —
2.5
300 —
—
—
— 200
RL = 300 Ω, maximum receive gain
Unit
kΩ
V
Ω
pF
—
2.3
1.6
—
3.0
2.5
Ω
V
2.3
—
2.5
V
4.01
—
—
VPP
Table 14. Gain and Dynamic Range
Parameter
Absolute Levels
Transmit Gain
Absolute Accuracy
Transmit Gain Variation
with Temperature
Transmit Gain Variation
with Programmed Gain
Lucent Technologies Inc.
Symbol
Test Conditions
GAL
Maximum 0 dBm0 levels:
VFXI (gain set to 11000011)
VFRO (gain set to 11000011)
Minimum 0 dBm0 levels:
VFXI (gain set to 00000001)
VFRO (gain set to 00000001)
Transmit gain programmed for
GXA
maximum 0 dBm0 test level,
measured deviation of digital
code from ideal 0 dBm0 PCM
code at DX0/1, TA = 25 °C
GXAT
Measured relative to GXA,
VDD = 5 V, minimum
gain < GX < maximum gain
GXAG Measured transmit gain over
the range from maximum to
minimum, calculated the deviation from the programmed gain
relative to GXA (i.e., GXAF =
Gactual – Gprog – GXA),
TA = 25 °C, VDD = 5 V
TA (°C)
Min
Typ
Max
Unit
—
—
—
—
0.811
0.987
—
—
Vrms
Vrms
—
—
—
—
—
–0.15
87.0
106.0
—
—
—
0.15
mVrms
mVrms
dB
–40 to 0
0 to 85
–0.15
–0.1
—
—
0.15
0.1
dB
dB
—
–0.1
—
0.1
dB
15
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Data Sheet
October 1996
Transmission Characteristics (continued)
Table 14. Gain and Dynamic Range (continued)
Parameter
Transmit Gain Variation
with Frequency
Transmit Gain Variation
with Signal Level
Receive Gain Absolute
Accuracy
Receive Gain
Variation with
Temperature
Receive Gain Variation
with Programmed Gain
16
Symbol
Test Conditions
TA (°C)
GXAF
Relative to 1020 Hz, minimum
gain < GX < maximum gain,
DR0 or DR1 = 0 dBm0 code:
f = 16.67 Hz
—
f = 50 Hz
—
f = 60 Hz
—
f = 200 Hz
—
f = 300 Hz to 3000 Hz
—
f = 3140 Hz
—
f = 3380 Hz
—
f = 3860 Hz
—
—
f ≥ 4600 Hz (measured
response at alias frequency
from 0 kHz to 4 kHz)
GXAL
Sinusoidal test method, reference level = 0 dBm0:
VFXI = –40 dBm0 to +3 dBm0
—
VFXI = –50 dBm0 to –40 dBm0
—
VFXI = –55 dBm0 to –50 dBm0
—
Receive gain programmed for
—
GRA
maximum 0 dBm0 test level,
applied 0 dBm0 PCM code to
DR0 or DR1, measured VFRO,
TA = 25 °C, load = 10 kΩ
GRAT
Measured relative to GRA, VDD = –40 to 0
5 V, minimum gain < GR < maxi- 0 to 85
mum gain
GRAG Measured receive gain over the
—
range from maximum to minimum setting, calculated the
deviation from the programmed
gain relative to GRA, i.e.,
GRAG = Gactual – Gprog – GRA,
TA = 25 °C, VDD = 5 V
Min
Typ
Max
Unit
—
—
—
–1.8
–0.125
–0.57
–0.885
—
—
–35
–33
–40
–0.5
±0.04
0.01
–0.6
–9.9
—
–30
–30
–30
0
0.125
0.125
0.012
–8.98
–32
dB
dB
dB
dB
dB
dB
dB
dB
dB
–0.2
–0.4
–1.2
–0.15
—
—
—
—
0.2
0.4
1.2
0.15
dB
dB
dB
dB
–0.15
–0.1
—
—
0.15
0.1
dB
dB
–0.1
—
0.1
dB
Lucent Technologies Inc.
Data Sheet
October 1996
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Transmission Characteristics (continued)
Table 14. Gain and Dynamic Range (continued)
Parameter
Receive Gain
Variation with
Frequency
Receive Gain
Variation with
Signal Level
Symbol
Test Conditions
GRAF Relative to 1020 Hz,
DR0 or DR1 = 0 dBm0 code,
minimum gain < GR < maximum gain:
f ≤ 3000 Hz
f = 3140 Hz
f = 3380 Hz
f = 3860 Hz
f ≥ 4600 Hz
GRAL Sinusoidal test method,
reference level = 0 dBm0:
DR0 = –40 dBm0 to +3 dBm0
DR0 = –50 dBm0 to –40 dBm0
DR0 = –55 dBm0 to –50 dBm0
TA (°C)
—
—
—
—
—
Min
Typ
–0.125 ±0.04
–0.57 0.01
–0.885 –0.58
—
–10.7
—
—
—
—
—
–0.2
–0.4
–1.2
—
—
—
Min
—
—
—
—
—
—
—
—
—
–40
–30
—
—
—
Max
315
220
145
75
40
75
105
155
200
—
—
90
125
175
Unit
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
Max
Unit
0.125
0.125
+0.012
–8.98
–28
dB
dB
dB
dB
dB
0.2
0.4
1.2
dB
dB
dB
Table 15. Envelope Delay Distortion
Parameter
Tx Delay, Absolute
Tx Delay, Relative
to 1600 Hz
Symbol
DXA
DXR
Rx Delay, Absolute
Rx Delay, Relative
to 1600 Hz
DRA
DRR
Lucent Technologies Inc.
Test Conditions
f = 1600 Hz
f = 500 Hz—600 Hz
f = 600 Hz—800 Hz
f = 800 Hz—1000 Hz
f = 1000 Hz—1600 Hz
f = 1600 Hz—2600 Hz
f = 2600 Hz—2800 Hz
f = 2800 Hz—3000 Hz
f = 1600 Hz
f = 500 Hz—1000 Hz
f = 1000 Hz—1600 Hz
f = 1600 Hz—2600 Hz
f = 2600 Hz—2800 Hz
f = 2800 Hz—3000 Hz
17
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Data Sheet
October 1996
Transmission Characteristics (continued)
Table 16. Noise
Parameter
Transmit Noise, C Message
Weighted, µ-law Selected
Transmit Noise, P Message
Weighted, A-law Selected
Receive Noise, C Message
Weighted, µ-law Selected
Receive Noise, P Message
Weighted, A-law Selected
Noise, Single Frequency
Symbol
Test Conditions
NXC
All 1s in gain register
Power Supply Rejection, Transmit
PPSRX
Power Supply Rejection, Receive
Spurious Out-of-Band Signals at
the Channel Output
Min Typ Max
—
—
15
Unit
dBrnC0
NXP
All 1s in gain register
—
—
–67
dBm0p
NRC
PCM code is alternating positive and
negative zeros
PCM code equals positive one LSB
—
—
13
dBrnC0
—
—
–79
dBm0p
f = 0 kHz—100 kHz, analog to analog
measurement (DX0 is externally connected to DR0), VFXI = 0 Vrms
VDD = 5.0 Vdc + 100 mVrms:
f = 0 kHz—4 kHz*
f = 4 kHz—50 kHz
PCM code equals positive one LSB,
VDD = 5.0 + 100 mVrms,
measured VFRO:
f = 0 Hz—4000 Hz
f = 4 kHz—25 kHz
f = 25 kHz—50 kHz
0 dBm0, 300 Hz—3400 Hz input
PCM code applied at DR0 (or DR1):
4600 Hz—7600 Hz
7600 Hz—8400 Hz
8400 Hz—50,000 Hz
—
—
–53
dBm0
36
30
—
—
—
—
dBC
dBC
36
40
36
—
—
—
—
—
—
dBC
dB
dB
—
—
—
—
—
—
–30
–40
–30
dB
dB
dB
NRP
NRS
PPSRR
SOS
* PPSRX is measured with a –50 dBm0 activation signal applied to VFXI.
18
Lucent Technologies Inc.
Data Sheet
October 1996
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Transmission Characteristics (continued)
Table 17. Distortion
Parameter
Signal to Total Distortion
Transmit or Receive
Half-channel, µ-law Selected
Single Frequency Distortion,
Transmit
Single Frequency Distortion,
Receive
Intermodulation Distortion
Symbol
STDX
STDR
SFDX
Test Conditions
Sinusoidal test method level:
3.0 dBm0
0 dBm0 to –30 dBm0
–40 dBm0
–45 dBm0
—
—
SFDR
IMD
Transmit or receive two frequencies
in the range (300 Hz—3400 Hz)
Min
Max
Unit
33
36
30
25
—
—
—
—
—
–46
dBC
dBC
dBC
dBC
dB
—
–46
dB
—
–41
dB
Table 18. Crosstalk
Parameter
Transmit to Receive Crosstalk,
0 dBm0 Transmit Level
Receive to Transmit Crosstalk,
0 dBm0 Receive Level
Symbol
Test Conditions
CTX–R f = 300 Hz—3400 Hz
DR = steady PCM code
CTR–X f = 300 Hz—3400 Hz*
Typ
–90
Max
–75
Unit
dB
–90
–70
dB
* CTR–X and PPSRX are measured with a –50 dBm0 activation signal applied to VFXI.
Lucent Technologies Inc.
19
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Data Sheet
October 1996
Timing Characteristics
A signal is valid if it is above VIH or below VIL and invalid if it is between VIL and VIH. For the purposes of this specification, the following conditions apply:
■
All input signals are defined as VIL = 0.4 V, VIH = 2.7 V, tR < 10 ns, tF < 10 ns.
tR is measured from VIL to VIH. tF is measured from VIH to VIL.
■
■
Delay times are measured from the input signal valid to the output signal valid.
■
Setup times are measured from the data input valid to the clock input invalid.
■
Hold times are measured from the clock signal valid to the data input invalid.
■
Pulse widths are measured from VIL to VIL or from VIH to VIH.
Table 19. Master Clock Timing (See Figures 4 and 5.)
Symbol
fMCLK
Parameter
Frequency of MCLK—Selection
Frequency Is Programmable
(See Table 3.)
Test Conditions
—
tMCHMCL
tMCLMCH
tMCH1MCH2
tMCL2MCL1
tBCLMCH
Time of MCLK High
Time of MCLK Low
Rise Time of MCLK
Fall Time of MCLK
Hold Time, BCLK Low to MCLK
High
Period of FSX or FSR Low
tFSLFSH
20
Measured from VIH to VIH
Measured from VIL to VIL
Measured from VIL to VIH
Measured from VIH to VIL
—
Min
—
—
—
—
80
80
—
—
50
Typ
1536
1544
2048
4096
—
—
—
—
—
Max
—
—
—
—
—
—
30
30
—
Unit
kHz
kHz
kHz
kHz
ns
ns
ns
ns
ns
Measured from VIL to VIL
1
—
—
MCLK
Period
Lucent Technologies Inc.
Data Sheet
October 1996
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Timing Characteristics (continued)
Table 20. PCM Interface Timing (See Figures 4 and 5.)
Symbol
fBCLK
tBCHBCL
tBCLBCH
tBCH1BCH2
tBCL2BCL1
tBCLFXL
tBCLFRL
tFXHBCL
tFRHBCL
tBCHDXV
tBCLDXZ
tBCHTXL
tBCLTXH
tFXHDXV
tDRVBCL
tBCLDRX
tBCLMCH
Parameter
Frequency of BCLK (can vary
from 64 kHz to 4096 kHz in
8 kHz increments)
Time of BCLK High
Time of BCLK Low
Rise Time of BCLK
Fall Time of BCLK
Hold Time, BCLK Low
FSX/R to High or Low
Setup Time FSX/R,
High to BCLK Low
Delay Time, BCLK High
to Data Valid
Delay Time, BCLK Low to
DX0/1 Disabled if FSX Low,
FSX Low to DX0/1 Disabled if
Eighth BCLK Low, or BCLK
High to DX0/1 Disabled if FSX
High
Delay Time, BCLK High to TS X
Low if FSX High, or FSX High
to TS X Low if BCLK High
High-impedance Time, BCLK
Low to TS X High if FSX Low,
or FSX BCLK High to TS X
High if FSX High
Delay Time, FSX/R
High to Data Valid
Setup Time, DR0/1
Valid to BCLK Low
Hold Time, BCLK Low to DR0/1
Invalid
BCLK Low to MCLK High at the
End of the First Data Bit
Period
Lucent Technologies Inc.
TA (°C)
—
Min
64
Max
4096
Unit
kHz
—
—
—
—
—
80
80
—
—
30
—
—
30
30
—
ns
ns
ns
ns
ns
—
30
—
ns
—
—
90
ns
–40 to 0
0 to 85
10
15
80
80
ns
ns
—
—
60
ns
—
—
15
60
ns
Load = 100 pF plus two
LSTTL loads, applies if FSX/R
rises later than BCLK rising
edge in nondelayed-data
mode only
—
—
—
80
ns
—
30
—
ns
–40 to 0
0 to 85
—
15
20
50
—
—
—
ns
ns
ns
Test Conditions
—
Measured from VIH to VIH
Measured from VIL to VIL
Measured from VIL to VIH
Measured from VIH to VIL
—
—
Load = 100 pF plus two
LSTTL loads
—
Load = 100 pF plus two
LSTTL loads
—
—
21
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Data Sheet
October 1996
Timing Characteristics (continued)
tMCH1MCH2
tMCHMCL
tMCL2MCL1
MCLK
(MC)
tBCL2BCL1
tBCLMCH
BCLK
(BC)
tMCLMCH
tBCH1BCH2
1
2
tBCHBCL
3
4
5
6
7
8
9
tBCLBCH
tBCLFXL
tFXHBCL
FSX
(FX)
tFXHDXV
tBCLDXZ
tBCHDXV
DX 0/1
(DX)
1
2
3
4
5
6
7
tBCHTXL
8
tBCLTXH
tBCHTXL
TSX0/1
(TX)
tFRHBCL
tBCLFRL
FSR
(FR)
tDRVBCL
DR 0/1
(DR)
1
tBCLDRX
2
3
4
5
6
7
8
5-2789 (C)
Note: Bit 1 = sign bit.
Figure 4. Nondelayed-Data Timing Mode
tMCH1MCH2
tMCL2MCL1
tMCHMCL
MCLK
(MC)
tBCLMCH
tBCL2BCL1
tMCLMCH
tBCH1BCH2
BCLK
(BC)
1
tBCHBCL
2
3
4
6
5
7
8
tBCLFXL
9
tBCLBCH
tFXHBCL
FSX
(FX)
tBCHDXV
DX 0/1
(DX)
tBCLDXZ
1
2
3
4
5
6
7
tBCHTXL
8
tBCLTXH
TSX0/1
(TX)
tBCLFRL
tFRHBCL
FSR
(FR)
tDRVBCL
DR 0/1
(DR)
1
2
tBCLDRX
3
4
5
6
7
8
5-2790 (C)
Note: Bit 1 = sign bit.
Figure 5. Delayed-Data Timing Mode
22
Lucent Technologies Inc.
Data Sheet
October 1996
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Timing Characteristics (continued)
Table 21. Serial Control Port Timing (See Figure 6.)
Symbol
fCCLK
tCCHCCL
tCCLCCH
tCCH1CCH2
tCCL2CCL1
tCCLCSL
tCCLCSH
Parameter
Frequency of CCLK
Time of CCLK High
Time of CCLK Low
Rise Time of CCLK
Fall Time of CCLK
Hold Time, CCLK Low to
CS Low
Hold Time, CCLK Low to
CS High
Test Conditions
—
Measured from VIH to VIH
Measured from VIL to VIL
Measured from VIL to VIH
Measured from VIH to VIL
Measured from first CCLK low transition
Min
—
160
160
—
—
10
Max
2048
50
50
—
Unit
kHz
ns
ns
ns
ns
ns
Measured from eighth CCLK low transition
100
—
ns
60
—
ns
tCSLCCH
Setup Time, CS Transition to CCLK Low
tCSHCCH
—
Setup Time, CS Transition to CCLK High
Setup Time, CI Data In to
—
CCLK Low
Hold Time, CCLK Low to
—
CI Invalid
Delay Time, CCLK High to Load = 100 pF plus 2 LSTTL loads
CO Data Out Valid
50
—
ns
50
—
ns
50
—
ns
—
80
ns
tCSLCOV
Delay Time, CS Low to
CO Valid
Applies only if separate CS used for byte 2
—
80
ns
tCSHCOZ
Delay Time, CS High to
CO High Impedance
Applies when CS high occurs before ninth
CCLK high
15
80
ns
Min
100
Max
—
Unit
ns
50
—
ns
—
200
ns
tCIVCCL
tCCLCIX
tCCHCOV
—
Table 22. Interface Latch Timing (See Figure 6.)
Symbol
Parameter
Test Conditions
tILXCCL Setup Time, IL to Eighth
Interface latch inputs only
CCLK of Byte 1
tCCLILX Hold Time, IL Valid from
—
Eighth CCLK Low (byte 1)
tCCLILV Delay Time CCLK 8 of
Interface latch outputs only CL = 50 pF
Byte 2 to IL
Table 23. Master Reset Pin
Symbol
Parameter
tMRHRML Duration of Master Reset High
Lucent Technologies Inc.
Min
1
Max
—
Unit
µs
23
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Data Sheet
October 1996
Timing Characteristics (continued)
CCLK
(CC)
1
2
3
4
5
6
tCCLCSL
7
8
1
3
4
6
7
8
tCCL2CCL1
tCCLCSL
tCCH1CCH2
BYTE 2
CS
tCCLCSH
tCSHCCH
tCIVCCL
CI:
BYTE 1 &
BYTE 2 WHEN
INPUT TO CI
5
tCSLCCH
tCCHCCL
tCCLCCH
tCSLCCH
2
tCCLCIX
7
6
5
4
3
2
1
0
7
6
tCCLCSH
5
4
3
2
1
tCSLCOV
0
tCSHCOZ
tCCHCOV
CO: BYTE 2
WHEN OUTPUT
FROM CO
(CO)
7
6
tILXCCL
tCCLILX
5
4
3
2
1
0
tCCLILV
IL5—IL0
(IL)
INPUTS ONLY
OUTPUTS ONLY
5-2791 (C)
Figure 6. Serial Control Port Timing
24
Lucent Technologies Inc.
Data Sheet
October 1996
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Applications
Figure 7 illustrates a T7570 codec interfaced to a Lucent L7554 SLIC. Interface components were chosen for a
basic 600 Ω resistive only termination and balance network. Overall receive path gain is 0 dB (PCM to T/R). Overall
transmit path gain is –2 dB (T/R to PCM). Codec receive gain is 0 dB. The signal level returned to VFXI is
–3.658 dBm. This satisfies the transmission level point requirement for hybrid cancellation. That is, the signal at
VFXI relative to the output at VFRO must be within –2.5 dB to –10.25 dB. Transmit gain of the codec is set at
+1.658 dB in order to achieve a transmission level point at Dx of –2 dBm.
Transmit and receive paths are capacitively coupled to accommodate different SLIC and codec bias levels. The
codec’s inputs are self-biased so that no additional external resistors are necessary with ac coupling. Capacitor
values are sized appropriately to pass low-frequency requirements of relevant gain versus frequency templates.
Resistive values were ascertained from SLIC documentation.
An optional 20 kΩ resistor from RCVN to ground and a 30 pF capacitor across RGP can be added for stability.
Gain and hybrid-balance register values are shown in hex. Gain values were obtained from Tables 8 and 9. Hybridbalance values were obtained by removing the codec and inserting a network analyzer to measure the phase and
gain returned by the loop to VFXI when a signal is injected at VFRO. Gain and phase are then measured at 14 frequencies. The results obtained from this exercise are plugged into the hybrid-balance software that provides the
register settings as shown.
L7554
RPT
35 Ω
T7570
CC1
0.47 µF
VITR
PT
VFXI
RT1
86.6 kΩ
TZ
600 Ω
RPT
35 Ω
CRCV1
0.1 µF
RCVN
PR
2.4 V
RCVP
RRCV
48.7 kΩ
SEE REGISTER
SETTINGS
BELOW
VFRO
RGP
20 kΩ
SLIC
CODEC
Register Settings
Register
Register Number Value
RX GAIN
TX GAIN
HYBRID 1
HYBRID 2
HYBRID 3
04
05
06
07
08
AE
AE
A4
51
88
Description
0 dB
1.658 dB
—
—
—
5-4716.a C
Figure 7. 600 Ω Resistive SLIC Interface
Lucent Technologies Inc.
25
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Data Sheet
October 1996
Outline Diagrams
28-Pin PLCC
Dimensions are shown in inches.
12.57 MAX
11.58 MAX
PIN #1 IDENTIFIER
ZONE
4
1
26
25
5
11.58
MAX
12.57
MAX
19
11
12
18
4.57 MAX
SEATING PLANE
1.27 TYP
0.51 MIN
TYP
0.10
0.53 MAX
5-2608r.4
26
Lucent Technologies Inc.
Data Sheet
October 1996
T7570 Programmable PCM Codec
with Hybrid-Balance Filter
Ordering Information
Device Code
T - 7570 - - - ML2
T - 7570 - - - ML2 -TR
Lucent Technologies Inc.
Package
28-Pin PLCC
28-Pin PLCC, Tape and Reel
Temperature
–40 °C to +85 °C
–40 °C to +85 °C
Comcode
107055782
107056525
27
For additional information, contact your Microelectronics Group Account Manager or the following:
INTERNET: http://www.lucent.com/micro
U.S.A.: Microelectronics Group, Lucent Technologies Inc., 555 Union Boulevard, Room 30L-15P-BA, Allentown, PA 18103,
1-800-372-2447, FAX 610-712-4106 (In CANADA: 1-800-553-2448, FAX 610-712-4106), e-mail docmaster@micro.lucent.com
ASIA PACIFIC: Microelectronics Group, Lucent Technologies Singapore Pte. Ltd., 77 Science Park Drive, #03-18 Cintech III, Singapore 118256
Tel. (65) 778 8833, FAX (65) 777 7495
JAPAN: Microelectronics Group, Lucent Technologies Japan Ltd., 7-18, Higashi-Gotanda 2-chome, Shinagawa-ku, Tokyo 141, Japan
Tel. (81) 3 5421 1600, FAX (81) 3 5421 1700
For data requests in Europe:
MICROELECTRONICS GROUP DATALINE: Tel. (44) 1734 324 299, FAX (44) 1734 328 148
For technical inquiries in Europe:
CENTRAL EUROPE: (49) 89 95086 0 (Munich), NORTHERN EUROPE: (44) 1344 865 900 (Bracknell UK),
FRANCE: (33) 1 47 67 47 67 (Paris), SOUTHERN EUROPE: (39) 2 6601 1800 (Milan) or (34) 1 807 1700 (Madrid)
Lucent Technologies Inc. reserves the right to make changes to the product(s) or information contained herein without notice. No liability is assumed as a result of their use or application. No
rights under any patent accompany the sale of any such product(s) or information.
Copyright © 1996 Lucent Technologies Inc.
All Rights Reserved
October 1996
DS96-223ALC (Replaces DS92-224TCOM and AY93-026TCOM)
Printed On
Recycled Paper