On Thu, 12 May 2011 21:16:15 +0100, "Ian Field"
wrote:
"Jim Thompson" wrote in
message ...
On Thu, 12 May 2011 20:38:39 +0100, "Ian Field"
wrote:
"Jim Thompson" wrote
in
message ...
On Thu, 12 May 2011 19:48:06 +0100, "Ian Field"
wrote:
"Sjouke Burry" wrote in message
.. .
Ian Field wrote:
Running at the full Vcc of 16V and the full frequency of 500kHz the
555
got so hot I had to add a clip-on heatsink.
Tried slowing it down to about 140kHz and the heatsink still gets
pretty
warm.
Is this normal?
Thanks.
Try again at a somewhat lower voltage, you may have exceeded
vcc for this particular unit and/or caused latching somewhere,
in which case almost the black magic smoke comes out.
Almost every datasheet I've seen says 16V - ISTR the Hitachi DS says
18V.
Perhaps a large capacitive load?
Been bench testing with no load (apart from driving the CR) and then with
a
BC327/337 complementary emitter follower pair.
Post your schematic or a link.
Its at the same location as my other PC with no internet.
Vcc is clamped by a 16V zener and has 680u + 334 mylar all fed by 68 Ohm
from VDD.
With CR= 3n3 & 8k2 its a standard astable except the CR is driven by pin 3
instead of pin 7 + pullup resistor.
There is the customary 10n from pin 5 to GND.
How do you post to SED ?:-)
...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice
480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at
http://www.analog-innovations.com | 1962 |
Obama is not the solution, Obama is the problem!