Datenblatt-Suchmaschine für elektronische Bauteile
  German  ▼
ALLDATASHEETDE.COM

X  

FM31272 Datenblatt(PDF) 8 Page - Ramtron International Corporation

Teilenummer FM31272
Bauteilbeschribung  5V Integrated Processor Companion with Memory
Download  25 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Hersteller  RAMTRON [Ramtron International Corporation]
Direct Link  http://www.ramtron.com
Logo RAMTRON - Ramtron International Corporation

FM31272 Datenblatt(HTML) 8 Page - Ramtron International Corporation

Back Button FM31272 Datasheet HTML 4Page - Ramtron International Corporation FM31272 Datasheet HTML 5Page - Ramtron International Corporation FM31272 Datasheet HTML 6Page - Ramtron International Corporation FM31272 Datasheet HTML 7Page - Ramtron International Corporation FM31272 Datasheet HTML 8Page - Ramtron International Corporation FM31272 Datasheet HTML 9Page - Ramtron International Corporation FM31272 Datasheet HTML 10Page - Ramtron International Corporation FM31272 Datasheet HTML 11Page - Ramtron International Corporation FM31272 Datasheet HTML 12Page - Ramtron International Corporation Next Button
Zoom Inzoom in Zoom Outzoom out
 8 / 25 page
background image
FM31278/276/274/272 - 5V I2C Companion
Rev. 2.0
Dec. 2007
Page 8 of 25
The calibration setting is stored in F-RAM so is not
lost should the backup source fail. It is accessed with
bits CAL.4-0 in register 01h. This value only can be
written when the CAL bit is set to a 1. To exit the
calibration mode, the user must clear the CAL bit to a
0. When the CAL bit is 0, the CAL/PFO pin will
revert to the power fail output function.
Crystal Oscillator
The crystal oscillator is designed to use a 12.5pF
crystal without the need for external components,
such as loading capacitors. The FM3127x device has
built-in loading capacitors that match the crystal.
If a 32.768kHz crystal is not used, an external
oscillator may be connected to the FM3127x. Apply
the oscillator to the X1 pin. Its high and low voltage
levels can be driven rail-to-rail or amplitudes as low
as approximately 500mV p-p.
To ensure proper
operation, a DC bias must be applied to the X2 pin.
It should be centered between the high and low levels
on the X1 pin. This can be accomplished with a
voltage divider.
In the example, R1 and R2 are chosen such that the
X2 voltage is centered around the X1 oscillator drive
levels. If you wish to avoid the DC current, you may
choose to drive X1 with an external clock and X2
with an inverted clock using a CMOS inverter.
Figure 8. External Oscillator
Layout Requirements
The X1 and X2 crystal pins employ very high
impedance circuits and the oscillator connected to
these pins can be upset by noise or extra loading. To
reduce RTC clock errors from signal switching noise,
a guard ring must be placed around these pads and
the guard ring grounded. SDA and SCL traces should
be routed away from the X1/X2 pads. The X1 and X2
trace lengths should be less than 5 mm. The use of a
ground plane on the backside or inner board layer is
preferred. See layout example. Red is the top layer,
green is the bottom layer.
Layout for Surface Mount Crystal
Layout for Through Hole Crystal
(red = top layer, green = bottom layer)
(red = top layer, green = bottom layer)
X1 X2
Vdd
FM3127x
R1
R2
VDD
SCL
SDA
X2
X1
PFI
VBAK
VDD
SCL
SDA
X2
X1
PFI
VBAK


Ähnliche Teilenummer - FM31272

HerstellerTeilenummerDatenblattBauteilbeschribung
logo
Ramtron International C...
FM31276 RAMTRON-FM31276 Datasheet
461Kb / 26P
   5V Integrated Processor Companion with Memory
logo
Cypress Semiconductor
FM31276 CYPRESS-FM31276 Datasheet
862Kb / 26P
   5V Integrated Processor Companion with Memory
FM31276-G CYPRESS-FM31276-G Datasheet
862Kb / 26P
   5V Integrated Processor Companion with Memory
FM31276-GTR CYPRESS-FM31276-GTR Datasheet
862Kb / 26P
   5V Integrated Processor Companion with Memory
logo
Ramtron International C...
FM31278 RAMTRON-FM31278 Datasheet
461Kb / 26P
   5V Integrated Processor Companion with Memory
More results

Ähnliche Beschreibung - FM31272

HerstellerTeilenummerDatenblattBauteilbeschribung
logo
Cypress Semiconductor
FM31278 CYPRESS-FM31278 Datasheet
862Kb / 26P
   5V Integrated Processor Companion with Memory
logo
Ramtron International C...
FM32278 RAMTRON-FM32278 Datasheet
274Kb / 21P
   5V Integrated Processor Companion with Memory
FM31278 RAMTRON-FM31278_11 Datasheet
461Kb / 26P
   5V Integrated Processor Companion with Memory
logo
List of Unclassifed Man...
FM3104 ETC1-FM3104 Datasheet
252Kb / 22P
   Integrated Processor Companion with Memory
FM3204 ETC1-FM3204 Datasheet
273Kb / 20P
   Integrated Processor Companion with Memory
logo
Ramtron International C...
FM31256 RAMTRON-FM31256_11 Datasheet
455Kb / 26P
   Integrated Processor Companion with Memory
FM3104 RAMTRON-FM3104 Datasheet
546Kb / 25P
   Integrated Processor Companion with Memory
logo
Cypress Semiconductor
FM31256-GTR CYPRESS-FM31256-GTR Datasheet
773Kb / 27P
   Integrated Processor Companion with Memory
FM31256-G CYPRESS-FM31256-G Datasheet
773Kb / 27P
   Integrated Processor Companion with Memory
logo
Ramtron International C...
FM31L278 RAMTRON-FM31L278 Datasheet
330Kb / 25P
   3V Integrated Processor Companion with Memory
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25


Datenblatt Download

Go To PDF Page


Link URL




Privatsphäre und Datenschutz
ALLDATASHEETDE.COM
War ALLDATASHEET hilfreich?  [ DONATE ] 

Über Alldatasheet   |   Werbung   |   Kontakt   |   Privatsphäre und Datenschutz   |   Linktausch   |   Hersteller
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com