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The Gunning Transceiver Logic - Transceiver Voltage Clamps (GTL-TVC) provide
high-speed voltage translation with low ON-state resistance and minimal propagation
delay. The GTL2003 provides eight NMOS pass transistors (Sn and Dn) with a common
gate (GREF) and a reference transistor (SREF and DREF). The device allows
bidirectional voltage translations between 0.8 V and 5.0 V without use of a direction pin.
Voltage translation below 0.8 V can be achieved when properly biased. For more
information, refer to application note AN11127.
When the Sn or Dn port is LOW, the clamp is in the ON-state and a low resistance
connection exists between the Sn and Dn ports. Assuming the higher voltage is on the Dn
port, when the Dn port is HIGH, the voltage on the Sn port is limited to the voltage set by
the reference transistor (SREF). When the Sn port is HIGH, the Dn port is pulled to VDD1
by the pull-up resistors. This functionality allows a seamless translation between higher
and lower voltages selected by the user, without the need for directional control.
All transistors have the same electrical characteristics and there is minimal deviation from
one output to another in voltage or propagation delay. This is a benefit over discrete
transistor voltage translation solutions, since the fabrication of the transistors is
symmetrical. Because all transistors in the device are identical, SREF and DREF can be
located on any of the other eight matched Sn/Dn transistors, allowing for easier board
layout. The translator's transistors provide excellent ESD protection to lower voltage
devices and at the same time protect less ESD-resistant devices.