73M1903-IVTR/F Maxim Integrated Products, 73M1903-IVTR/F Datasheet - Page 10

• Manufacturer Part Number: 73M1903-IVTR/F
• Description: IC MODEM AFE V.22BIS 20-TSSOP
• Manufacturer: Maxim Integrated Products

Specifications of 73M1903-IVTR/F

• Number Of Channels: 2
• Voltage - Supply, Analog: 3 V ~ 3.6 V
• Voltage - Supply, Digital: 3 V ~ 3.6 V
• Package / Case: 20-TSSOP (0.173", 4.40mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power (watts): -
• Number Of Bits: -

2.1
2.2
as either an input or an output by a bit in a direction register. If the bit in the direction register is set high,
the corresponding pin is an input whose value is read from the GPIO data register. If it is low, the pin will
be treated as an output whose value is set by the GPIO data register.
To avoid unwanted current contention and consumption in the system from the GPIO port before the
GPIO is configured after a reset, the GPIO port I/Os are initialized to a high impedance state. The input
structures are protected from floating inputs, and no output levels are driven by any of the GPIO pins.
The GPIO pins are configured as inputs or outputs when the host controller (or DSP) writes to the GPIO
direction register. The GPIO direction and data registers are initialized to all ones (FFh) upon reset.
transmit and receive signals to and from the external circuitry.
The hybrid driver in the 73M1903 IC is capable of connecting directly, but not limited to, a transformer-
based Direct Access Arrangement (DAA). The hybrid driver is capable of driving the DAA’s line coupling
transformer, which carries an impedance on the primary side that is typically rated at 600 Ω, depending
on the transformer and matching network. The hybrid drivers can also drive high impedance loads
without modification. The class AB behavior of the amplifiers provides load dependent power
consumption.
An on-chip band gap voltage is used to provide an internal voltage reference and bias currents for the
analog receive and transmit channels. The reference derived from the bandgap, nominally 1.25 Volts, is
multiplied to 1.36 Volts and output at the VREF pin. Several voltage references, nominally 1.25 Volts, are
used in the analog circuits. The band gap and reference circuits are disabled after a chip reset since the
ENFE bit is reset to a default state of zero. When ENFE=0, the band gap voltage and the analog bias
currents are disabled. In this case all of the analog circuits are powered down and draw less than 5 μA of
current.
A clock generator (CKGN) is used to create all of the non-overlapping phase clocks needed for the time
sampled switched-capacitor circuits, ASDM, DAC1, and TLPF. The CKGN input is two times the
analog/digital interface sample rate or 3.072 MHz clock for Fs=8 kHz.
73M1903 Data Sheet
The 73M1903 modem AFE device provides 8 user defined I/O pins. Each pin is programmed separately
2.1.1 GPIO Data (GPIO): Address 02h
Reset State FFh
Bits in this register will be asserted on the GPIO(7:0) pins if the corresponding direction register bit is a 0.
Reading this address will return data reflecting the values of pins GPIO(7:0).
2.1.2 GPIO Direction (DIR): Address 03h
Reset State FFh
This register is used to designate the GPIO pins as either inputs or outputs. If the register bit is low, the
corresponding GPIO pin is programmed as an output. If the register bit is a 1, the corresponding pin will
be treated as an input.
Figure 4
10
Bit 7
GPIO7
Bit 7
DIR7
GPIO
Analog I/O
shows the block diagram of the analog front end. The analog interface circuit uses differential
Bit 6
GPIO6
Bit 6
DIR6
Bit 5
GPIO5
Bit 5
DIR5
Bit 4
GPIO4
Bit 4
DIR4
Bit 3
GPIO3
Bit 3
DIR3
Bit 2
GPIO2
Bit 2
DIR2
Bit 1
GPIO1
Bit 1
DIR1
Bit 0
DIR0
Bit 0
GPIO0
DS_1903_032
Rev. 2.1