How to convert digital logic from 3.3V <--> 1.8V ?

[wylee]

how to convert 5 logic to 3.3

I would like to

1. convert a digital logic signal from 3.3V to 1.8V
2. convert a digital logic sginal from 1.8V to 3.3V

What kind of circuit which can achieve this without degrading the signal quality (e.g: duty cycle) ?

 

[IanP]

convert 1.8v to 3.3v

FXLP34 Single Bit Uni-Directional Translator

- 1.0V to 3.6V VCC supply operation ..
- Converts any voltage (1.0V to 3.6V) to (1.0V to 3.6V) ..
- 4.6V tolerant inputs and outputs ..

General Description

The FXLP34 is a single translator with two separate supply voltages: V CC1
for input translation voltages and V CC for output translation voltages ..

https://www.fairchildsemi.com/ds/FX/FXLP34.pdf

Regards,
IanP

 

[wylee]

how to convert 1.8v to 3.3v

IanP,

Actually, I was hoping to know the internal circuit/schematics of such translator instead of buying/using the chip you recommended.

 

[DenisMark]

converting 3.3v to 1.8v logic

1. Input buffer with pass transistor see "Basic ESD and I/O design" book for example or resistor attenuator, or diff. pair
2. Differential logic and it's other modification

 

[wylee]

ic which convert 3.3v dc to 1.8v dc

DenisMark,

This is the book you are referring right?

Basic ESD and I/O Design
by Sanjay Dabral, Timothy Maloney

Hardcover: 328 pages ; Dimensions (in inches): 0.88 x 9.52 x 6.41
Publisher: Wiley-Interscience; 1 edition (November 30, 1998)

 

[DenisMark]

3.3 to 1.8 v logic

Yes.
For differential logic (aka levelshift circuits) go to uspto.org to us patents searching, there are many examples. Full patents in pdf format it's easy download from wikipatents.com. See also IEEE publication if u have.

 

[PaulHolland]

1.8 to 3.3 converter digital

Hi, You can use a small N MOSFET !. Not as inverter but by connecting the gate to vcc1 and using two resistors for pull-up. VCC1 < VCC2.

Connect the gate to VCC1 and use a pull-up from VCC1 to source, also use a pull-up from VCC2 to drain. the source is now the low voltage logic input/output and the drain the high voltage logic input/output.

use Si1912EDH MOSFET's or other low threshold mosfets. Do not use 2N7002 since they have a to high threshold voltage.

works perfect.

Paul.

 

[goldy.]

1.8 logic thresholds

one can convert a digital signal in to digital but can change its o/p acc to his needs

it can be possible with the help of dc-dc (dc to dc) converter.

 

[wylee]

convert from 1.8v to 3.3

Hi, You can use a small N MOSFET !. Not as inverter but by connecting the gate to vcc1 and using two resistors for pull-up. VCC1 < VCC2.

Connect the gate to VCC1 and use a pull-up from VCC1 to source, also use a pull-up from VCC2 to drain. the source is now the low voltage logic input/output and the drain the high voltage logic input/output.

use Si1912EDH MOSFET's or other low threshold mosfets. Do not use 2N7002 since they have a to high threshold voltage.

works perfect.

Paul.

Can you attached a small diagram describing the connection for proper understading? And I am using this in chip level IC design...so I won't be getting discrete component like 2N7002