DS1337 RTC+Supercap+7805 I2C module v3
author: Heisenbug
2 layer board of 1.00 x 0.90 inches (25.4 x 22.9 mm)
Uploaded:
March 28, 2015
Shared:
March 29, 2015
Total Price:
$4.45
$4.45 / set of 3
Physical assembly designed with the intent to be used in more of a vertical orientation, e.g. on a right-angle header plugged into a breadboard.
Batteryless clock module - now more shrinky than the old version!
Features access to all DS1337 IO pins plus a separate IO voltage supply for their pull-up resistors, and accessible connections to both sides of the discharge-blocking diode between the supercap and regulator.
DS1337S on top, Supercap (I chose a 1.5F that happens to have 30+ohm ESR) and 78L05 (SOIC version 5-volt regulator) on bottom, and one or a pair of [low-Vf] diodes makes for a batteryless clock module that will happily keep time with somewhere around monthly charging, on anything from 7+v (using regulator) or can be run direct on 1.8-5v.
Other passives on board bottom include 2 ceramic SMD caps (0.1u suggested) and 3 of the 4 SMD 0805 10k resistors, and on board top, 2 small electrolytic/tantalum, the last SMD 0805 10k resistor and the optional alternate PTH 10k resistor.
Charge session[s] should total 24-48 hours per month for better results with high-ESR supercaps.
The regulator can also power other small circuitry; just keep in mind power dissipation and current rating (~1W or 100mA).
$4.45 / set of 3
Physical assembly designed with the intent to be used in more of a vertical orientation, e.g. on a right-angle header plugged into a breadboard.
Batteryless clock module - now more shrinky than the old version!
Features access to all DS1337 IO pins plus a separate IO voltage supply for their pull-up resistors, and accessible connections to both sides of the discharge-blocking diode between the supercap and regulator.
DS1337S on top, Supercap (I chose a 1.5F that happens to have 30+ohm ESR) and 78L05 (SOIC version 5-volt regulator) on bottom, and one or a pair of [low-Vf] diodes makes for a batteryless clock module that will happily keep time with somewhere around monthly charging, on anything from 7+v (using regulator) or can be run direct on 1.8-5v.
Other passives on board bottom include 2 ceramic SMD caps (0.1u suggested) and 3 of the 4 SMD 0805 10k resistors, and on board top, 2 small electrolytic/tantalum, the last SMD 0805 10k resistor and the optional alternate PTH 10k resistor.
Charge session[s] should total 24-48 hours per month for better results with high-ESR supercaps.
The regulator can also power other small circuitry; just keep in mind power dissipation and current rating (~1W or 100mA).
