stlc1511 STMicroelectronics, stlc1511 Datasheet - Page 4

• Manufacturer Part Number: stlc1511
• Description: Northenlite?? G.lite Bicmos Analog Front-end Circuit
• Manufacturer: STMicroelectronics

STLC1511
Table 1. Pin Assignement
3.0 FUNCTIONAL DESCRIPTION
3.1 General Functional Description
The STLC1511 consists of the following functional
blocks:
The transmit path contains the 14-bit digital to analog
converter (DAC) necessary to generate the transmit
signal from a 14-bit digital input word. This transmit
signal is then scaled by the on chip programmable
gain amplifier (TxPGA) from 0 to -32dB in 2dB steps.
The scaled output signal is then driven off chip to the
external filters and power amplifier (PA) which drives
the DMT signal to the subscriber loop. The transmit
path is fully differential but may be used single ended
if both outputs from the TxPGA are terminated cor-
rectly.
The receive path contains an optional unity gain buff-
er followed by a two stage programmable gain ampli-
fier (RxPGA), a 1st order low pass anti-aliasing filter,
and a 12-bit analog to digital converter (ADC). The
RxPGA consists of two stages and the gain is digitally
programmable from 0 to 40dB in 0.5dB steps. The re-
ceive path is fully differential but may be used single
ended provided the other input to the RxPGA is
grounded.
The STLC1511 contains the circuits required to con-
4/31
Pin #
59
60
61
62
63
64
Transmit Signal Path
Receive Signal Path
Phase Lock Loop and Amplifier for an external
oscillator.
Bias Voltage and Current Generation
Digital Interface
Serial Interface
<1>HCMOS5 guidelines are for 1 pair of power/ground for 4 output drivers (4mA)
<2>Pins 35 and 43 are both connected to the analog VCC supplying the on chip oscillator. Similarly, Pins 34 and 42 are connected
to analog VSS for the oscillator. Supply line inductance is reduced using two pads for VCC (and VSS) in this manner. At the board
level, Pins 35 and 43 should be connected to analog VCC, and pins 34 and 42 should be connected to analog VSS.
QVEEDAC
RESETN
TXSIN[0]
TXSIN[1]
FRMCLK
VSSDIG1
Pin Name
VEE
DI
DI
DI
DO
VSS
Pin Type
VSSCO
TLCHT
TLCHT
TLCHT
BT4CR
VSSCO
Pad Type
struct a PLL that generates either a 17.644MHz/
when supplied with an external LC or crystal oscilla-
tor and tuning circuit. This clock is supplied to the
both the transmit and receive converters, and the se-
rial interface used to transfer the Rx/Tx data between
the STLC1511 and digital chip. The STLC1511 also
has the ability to be driven directly by an external
35.328MHz clock supplied to the FREF pin.
The bias circuitry contains a bandgap voltage refer-
ence from which the converter references and analog
ground voltage is generated. This block also gener-
ates an accurate current using an external resistor
from which all of the STLC1511 circuits are biased. In
addition, the bias circuitry also generates a 2.5V ref-
erence for the external Vco/Vcxo components and
can be used for other external circuits if necessary.
There is a 4 pin serial digital interface (DTX, DRX,
DIGCLK, ENB) that loads a one of four 8-bit control
SIN[0:1]), two receive pins (RXSOUT[1:0]), and the
necessary control signals (FRMCLK, CK35M) to
transmit the required data. For more information See
“Serial Interface” on page 18.
35.328 MHz clock from a 2.56 MHz reference clock
register that controls all the programmable features
on the STLC1511. Refer to “Digital Interface And
Memory Map” on page 20 for more information on
the programmability of the AFE.
To facilitate data transfer between the STLC1511
and the digital ASIC (STLC1510), a 2-bit wide serial
interface for the transmit path and a 2-bit wide serial
interface for the receive path is incorporated into the
AFE. This interface consists of two transmit pins (TX-
Quiet ground for DAC circuitry
ResetN for the AFE
Tx serial data (lsb) input
Tx serial data (msb) input
Tx 4.416MHz frame clock reference output
Ground (digital) for ADC and DAC
Description