Continue to Site

Welcome to

Welcome to our site! is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

driver 7 segments display and multipexation

Not open for further replies.


Junior Member level 2
Apr 8, 2001
Reaction score
Trophy points
Activity points
hi I need an chip whit multiplexation of display of 7 segments and conversion bcd.

i need driver 3 displays whit 1 chip

u know anybody?

You can use Maxim MAX7219

The MAX7219/MAX7221 are compact, serial input/output common-cathode display drivers that interface microprocessors (µPs) to 7-segment numeric LED displays of up to 8 digits, bar-graph displays, or 64 individual LEDs. Included on-chip are a BCD code-B decoder, multiplex scan circuitry, segment and digit drivers, and an 8x8 static RAM that stores each digit. Only one external resistor is required to set the segment current for all LEDs. The MAX7221 is compatible with SPI™, QSPI™, and Microwire™, and has slew-rate- limited segment drivers to reduce EMI.
A convenient 3-wire serial interface connects to all common µPs. Individual digits may be addressed and updated without rewriting the entire display. The MAX7219/MAX7221 also allow the user to select code-B decoding or no-decode for each digit.

The devices include a 150µA low-power shutdown mode, analog and digital brightness control, a scan-limit register that allows the user to display from 1 to 8 digits, and a test mode that forces all LEDs on.

if this is to display converted analog values, you can also use the ICL7xxx family (avail. at maxim web site too)

i need chip whit in of 4 lines , serial in dont work for mi circuit( dont have micro)


hello pal,

wanna an advise?... this MAX IC's are great but they're extremelly expensive to a simple 7 segment ckt.... I'd advise you to use a 4511, some analog switches and some BC337 to do the job, simple, clean, easy to find and CHEAP....



did your try 74xx926 ??


Many years ago I made such display, using 74188 PROM like hex - BCD convertor. Because I made signature analyzers, I needed some decoder like 74145, but to yield readable codes on 7 segment indicator. For sure you can get now many other PROMS.
Then you need generator for scanning, one register of 74173 (with TRISTATE)... for every digit - one chip.

Now, when having PIC for me will be 2-3 or less hours job to make such display. So, if you asking me - try to implement some uP. Cheaper, better, faster... any kind of digits, less elements.


i will recommend that u check the maximwebsite, because previously a scheme was theere that u can order few ic's that u want for free. so check now if it is also in progress.

try this!
It's a eight 7-segment displays and have 4 input (single chip)

/ Edit - Article from Elektor Electronics 12/2002.


/ Warning #1 - No thanks at Elektroda! /

is this chip easly available?

look at appnote 557 from microchip
it explains all this, with schematic and source code for interfacing led displays and pic

you also have details for interfacing the keypad simultaneously.

**broken link removed**

Re: advise

2000 said:
wanna an advise?... this MAX IC's are great but they're extremelly expensive to a simple 7 segment ckt....

You can order free samples of all Maxim ICs online, it doesn't get cheaper than that.

Not open for further replies.

Part and Inventory Search

Welcome to