Re: AVR32 availablilty ?
- From: "Ulf Samuelsson" <ulf@xxxxxxxxxxxxx>
- Date: Wed, 7 Nov 2007 22:59:56 +0100
Hey, how come the AVR32 requires so many decoupling caps, you guys use
26(!) for your 64 pin eval board, i think that's a record for a 64 pin
device
Someone wanted to clean out the stock of capacitors I guess.
STM32 recommends 7 on their 100 pin parts.
Here is the recommendation from the product line:
For VDDPLL, VDDCORE and VDDIO, you should place a
10nF and 100nF capacitors in parallel per a group of 4 pins.
In addition you need to place one common 'bulk' for
VDDPLL, VDDCORE and VDDIO with a value equal to C = I*dT/dV
dT = frequency of this application
dV = maximum of noise acceptable (50mV is a good choice)
I = current consumption of circuit
In that case the AVR32 needs 11 capacitors for a 64 pins.
================================================================
STM32F10 (from http://www.st.com/stonline/products/literature/an/13675.pdf)
VDD pins: (five 100 nF ceramic capacitor + one Tantalum capacitor (min. 4.7
?F typ.10 ?F).
VBAT pin must be connected to the external battery (1.8 V < VBAT < 3.6 V).
if no external battery is used, this pin must be connected to
VDD with a 100 nF external ceramic stabilization capacitor.
The VDDA pin must be connected to two external stabilization capacitors
(10 nF ceramic + 1 ?F Tantalum).
The VREF+ pin can be connected to the VDDA external power supply.
If a separate, external reference voltage is applied on VREF+,
two 10 nF and 1 ?F capacitors must be connected on this pin.
In all cases, VREF+ must be kept between 2.0 V and VDDA.
VDD: 6 caps
VBAT: 1 cap or 1 battery
VDDA: 2 caps
VREF: 0/2 caps
Looks like STM32F10x need 8-11 caps, depending on configuration.
--
Best Regards,
Ulf Samuelsson
This is intended to be my personal opinion which may,
or may not be shared by my employer Atmel Nordic AB
.
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