Functional Blocks - Revision history

Arclight: /* Real-time Clock */

2011-11-20T22:04:34Z

Real-time Clock

← Older revision		Revision as of 15:04, 20 November 2011
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	** NXP		** NXP
	***PCF8563		***PCF8563
			*Crystal
			** [http://www.maxim-ic.com/app-notes/index.mvp/id/58 Maxim Crystal Selection Notes]

	=== External Power Rails ===		=== External Power Rails ===

2011-11-12T22:58:54Z

General PCB layout

2011-11-12T22:57:20Z

Terminals

← Older revision		Revision as of 15:57, 12 November 2011
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	**Pluggable, right-angle		**Pluggable, right-angle
	**Non-Pluggable		**Non-Pluggable

			===General PCB layout===

			*PCB Specs
			**FR4 PCB material
			**0.62" substrate thickness
			**1oz Copper
			**HASL finish or Gold
			**Double-sided with PTH and vias
			**Solder Mask both sides
			**Silk-screened legend on both sides

			*Grounding
			**Continuous ground plane or mesh on bottom layer
			**Optional double ground or power plane on top layer
			**Exposed ground plane at case screw holes
			**Separate ground for differential signals as needed

2011-11-12T22:50:52Z

External Power Rails

← Older revision		Revision as of 15:50, 12 November 2011
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	=== External Power Rails ===		=== External Power Rails ===
	* Overvoltage protection		* Overvoltage protection
			** MOVs
			**TVS diodes

	*Overcurrent protection		*Overcurrent protection
			**High-side switching ICs with built-in protection
			**Polyfuses
	* ESD Protection		* ESD Protection
	**TVS diodes		**TVS diodes
	**Decoupling caps		**Decoupling caps
	**High-side switching ICs with built-in protection
	**Polyfuses

	=== Terminals ===		=== Terminals ===

2011-11-12T22:49:21Z

Logic pull-up

← Older revision		Revision as of 15:49, 12 November 2011
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	=== Logic pull-up ===		=== Logic pull-up ===
	* Internal pull-up resistor (software addressable)		* Internal pull-up resistor (software addressable)
			**Provides ~50K impedence
			**Some logic pins may not have pull-ups avialable
			**Weak compared to external resistor/state easily changed
	* External 10K resistor		* External 10K resistor
			**Robust, simple
			**Not as flexible as internal pull-ups
			**Can be configurable via jumper

	=== RS-485 Circuit ===		=== RS-485 Circuit ===

2011-11-12T22:47:17Z

Logic input protection

← Older revision		Revision as of 15:47, 12 November 2011
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	***May cause problems with data signals		***May cause problems with data signals
	*ESD Suppression chips		*ESD Suppression chips
			*Op-Amp on inputs
			**Provides impedence matching and logic buffering
			**Good choice for high-impedence and other non-standard devices

	=== Logic pull-up ===		=== Logic pull-up ===

2011-11-12T22:46:01Z

Relays

← Older revision		Revision as of 15:46, 12 November 2011
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	** Omron G5LE-14 DC12 (10A, square)		** Omron G5LE-14 DC12 (10A, square)
	* No ground plane on output traces		* No ground plane on output traces
	* ~~Spacing~~ for 250V+ voltage rating		* Trace separation for 250V+ voltage rating

	=== Logic input protection ===		=== Logic input protection ===

2011-11-12T22:45:16Z

Power Input Protection

← Older revision		Revision as of 15:45, 12 November 2011
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	*** Quick rise time		*** Quick rise time
	* LC or capacitor filtering		* LC or capacitor filtering
	** Good for fast pulses, general ESD filtering		** Good for fast pulses, general ESD filtering and immunity

	=== Internal Power Supply ===		=== Internal Power Supply ===

2011-10-31T20:13:06Z

External Power Supply

← Older revision		Revision as of 13:13, 31 October 2011
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	* Integrated or external battery backup		* Integrated or external battery backup
	** 12V sealed lead-acid		** 12V sealed lead-acid
			** Connection point for monitoring DC/Battery voltage

	===Power Input Protection===		===Power Input Protection===

2011-10-31T17:43:31Z

Logic input protection

← Older revision		Revision as of 10:43, 31 October 2011
Line 47:		Line 47:
	***May cause problems with data signals		***May cause problems with data signals
	*ESD Suppression chips		*ESD Suppression chips

			=== Logic pull-up ===
			* Internal pull-up resistor (software addressable)
			* External 10K resistor

	=== RS-485 Circuit ===		=== RS-485 Circuit ===