Voltage mode driver with enhanced transmit hybrid circuit

1. A voltage mode transceiver having an input/output (I/O) node for coupling to a bidirectional signaling link, the transceiver comprising:

a transmit circuit having an output coupled to the node, the transmit circuit including

a transmit digital-to-analog converter (DAC) circuit including

a transmit impedance network to generate an analog transmit version of a digital data signal, wherein the analog transmit version of the data signal comprises a signal having one of at least three possible voltage levels, and

a hybrid impedance network coupled to the transmit impedance network to generate an analog minor version of the digital data signal; and

a receive circuit having a first input coupled to the I/O node, and a second input coupled to receive the analog mirror version of the digital data signal;

wherein the transmit circuit and the receive circuit are operable to transmit and receive signals along the bidirectional signaling link simultaneously.

2. The transceiver according to claim 1 wherein the bidirectional signaling link exhibits a characteristic impedance and the receive circuit includes a receiver impedance network, and wherein:

the transmit impedance network, the hybrid impedance network, and the receiver impedance network substantially match the characteristic impedance of the bidirectional signaling link.

3. The transceiver according to claim 2 wherein the hybrid receiver impedance network is interposed between the transmit impedance network and the receiver impedance network.

4. The transceiver according to claim 1 wherein:

the transmit impedance network comprises a plurality of resistor branches disposed in parallel for selective activation by a control circuit, each resistor branch including first and second resistors joined at a common output node, the first resistor coupled to a first power supply voltage, the second resistor coupled to a second power supply voltage.

5. The transceiver according to claim 4 wherein the first power supply voltage comprises V DD , and the second power supply voltage comprises V SS .

6. The transceiver according to claim 1 wherein:

the transmit impedance network comprises a plurality of resistor branches disposed in parallel for selective activation by a control circuit, each resistor branch including first, second and third resistors joined at a common output node, the first resistor coupled to a first power supply voltage of a first value, the second resistor coupled to a second power supply voltage of a second value, and the third resistor coupled to a voltage source having a third value between the first and second values.

7. The transceiver according to claim 1 wherein:

the hybrid impedance network comprises a plurality of resistor branches disposed in parallel for selective activation by a control circuit, each resistor branch including first and second resistors joined at a common output node, the first resistor coupled to a first power supply voltage, the second resistor coupled to a second power supply voltage.

8. The transceiver according to claim 7 wherein the first power supply voltage comprises V DD , and the second power supply voltage comprises V SS .

9. The transceiver according to claim 8 wherein:

the hybrid impedance network comprises a plurality of hybrid resistor branches disposed in parallel for selective activation by the control circuit, each hybrid resistor branch including first, second and third hybrid resistors joined at a common output node, the first hybrid resistor coupled to a first power supply voltage of a first value, the second hybrid resistor coupled to a second power supply voltage of a second value, and the third hybrid resistor coupled to a voltage source having a third value between the first and second values.

10. The transceiver according to claim 1 embodied as a 10GBASE-T Ethernet transceiver circuit.