phpmyadmin logs out after 1440 secs

Add this line to /config.inc.php:

$cfg['LoginCookieValidity'] = 36000;

In /setup/lib/index.lib.php

$cf->getValue('LoginCookieValidity') > 36000;

If you don't already have a .htaccess file for your phpMyAdmin site, create one, and add the following line to override the default PHP session timeout:

php_value session.gc_maxlifetime 36000

I would not recommend altering this value in your main php.ini file, as it will allow a ridiculously long session timeout for all your PHP sites.

source: http://www.sitekickr.com/blog/increase-phpmyadmin-timeout/

Go to PHPMyAdmin in your browser

Settings > Features > Change the value of Login cookie validity > Save

NOTE: You will have to do this per session.