NLSX4378_12 Datasheet, PDF (8/9 Pages) ON Semiconductor – 4-Bit 24 Mb/s Dual-Supply Level Translator

NLSX4378
APPLICATIONS INFORMATION
Level Translator Architecture
The NLSX4378 auto sense translator provides
bi−directional voltage level shifting to transfer data in
multiple supply voltage systems. This device has two
supply voltages, V_L and V_CC, which set the logic levels on
the input and output sides of the translator. When used to
transfer data from the V_L to the V_CC ports, input signals
referenced to the V_L supply are translated to output signals
with a logic level matched to V_CC. In a similar manner, the
V_CC to V_L translation shifts input signals with a logic level
compatible to V_CC to an output signal matched to V_L.
The NLSX4378 consists of two bi−directional channels
that independently determine the direction of the data flow
without requiring a directional pin. The one−shot circuits
are used to detect the rising input signals. In addition, the
one shots decrease the rise time of the output signal for
low−to−high transitions.
Each input/output channel has an internal 10 kW pull.
The magnitude of the pullup resistors can be reduced by
connecting external resistors in parallel to the internal
10 kW resistors.
Input Driver Requirements
The rise (t_R) and fall (t_F) timing parameters of the open
drain outputs depend on the magnitude of the pull−up
resistors. In addition, the propagation times (t_PD), skew
(t_PSKEW) and maximum data rate depend on the impedance
of the device that is connected to the translator. The timing
parameters listed in the data sheet assume that the output
impedance of the drivers connected to the translator is less
than 50 W.
Enable Input (EN)
The NLSX4378 has an Enable pin (EN) that provides
tri−state operation at the I/O pins. Driving the Enable pin
to a low logic level minimizes the power consumption of
the device and drives the I/O V_CC and I/O V_L pins to a high
impedance state. Normal translation operation occurs
when the EN pin is equal to a logic high signal. The EN pin
is referenced to the V_L supply and has Overvoltage
Tolerant (OVT) protection.
Power Supply Guidelines
During normal operation, supply voltage V_L can be
greater than, less than or equal to V_CC. The sequencing of
the power supplies will not damage the device during the
power up operation.
For optimal performance, 0.01 mF to 0.1 mF decoupling
capacitors should be used on the V_L and V_CC power supply
pins. Ceramic capacitors are a good design choice to filter
and bypass any noise signals on the voltage lines to the
ground plane of the PCB. The noise immunity will be
maximized by placing the capacitors as close as possible to
the supply and ground pins, along with minimizing the
PCB connection traces.
ORDERING INFORMATION
Device
Package
Shipping^†
NLSX4378FCT1G
mBump12
(Pb−Free)
3000 / Tape & Reel
NLSX4378BFCT1G
mBump12
(Backside Laminate Coating)
(Pb−Free)
3000 / Tape & Reel
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
http://onsemi.com
8