r5548 - trunk/gta02-core/docs/ecn

rehar at docs.openmoko.org rehar at docs.openmoko.org
Wed Aug 26 23:39:54 CEST 2009


Author: rehar
Date: 2009-08-26 23:39:54 +0200 (Wed, 26 Aug 2009)
New Revision: 5548

Modified:
   trunk/gta02-core/docs/ecn/ecn0032.txt
   trunk/gta02-core/docs/ecn/ecn0033.txt
Log:
- removed CRLF in ECN0032
- changed C3008 to C3006, added C4406 and added possible capacitors to ECN0033

Modified: trunk/gta02-core/docs/ecn/ecn0032.txt
===================================================================
--- trunk/gta02-core/docs/ecn/ecn0032.txt	2009-08-26 21:37:47 UTC (rev 5547)
+++ trunk/gta02-core/docs/ecn/ecn0032.txt	2009-08-26 21:39:54 UTC (rev 5548)
@@ -1,26 +1,27 @@
-Add EMI and ESD protection to headset jack
-
-
-To prevent destroying the codec from any discharge we need to add a proper 
-ESD protection.
-We might still get RF feeding through the headset jack into the codec/system. 
-To be 100% sure it's best to add low pass EMI filter in all signal lines of the
-headset jack.
-
-based on Joerg's proposal!
-
-ESD protection 
-- add varistors (D4403/4404/4405) 5.6Vac to all headset jack signal pins
-  (same as D4402)
-
-EMI protection 
+Add EMI and ESD protection to headset jack
+
+
+To prevent destroying the codec from any discharge we need to add a proper
+ESD protection.
+We might still get RF feeding through the headset jack into the codec/system.
+To be 100% sure it's best to add low pass EMI filter in all signal lines of the
+headset jack.
+
+based on Joerg's proposal!
+
+ESD protection
+- add varistors (D4403/4404/4405) 5.6Vac to all headset jack signal pins
+  (same as D4402)
+
+EMI protection 
 - add Pi-filter to all signal lines of the headset jack 
-  (see ecn0032/pi-filter.png)
-  C1=47pF C2=47pF B=BLM15HD102SN1 1R25(DC) 
-  possible references C4408-C4415, B4415-B4419
-- remove 22pF capacitors C4403/4404/4405
-- remove common mode choke B4102 
-
-attenuation: f=1..3GHz approx 55dB(IN)/68dB(OUT) (150pF varistor)
-
+  (see ecn0032/pi-filter.png)
+  C1=47pF C2=47pF B=BLM15HD102SN1 1R25(DC) 
+  possible references C4408-C4415, B4415-B4419
+- remove 22pF capacitors C4403/4404/4405
+- remove common mode choke B4102 
+
+attenuation: f=1..3GHz approx 55dB(IN)/68dB(OUT) (150pF varistor)
+
+
 Author: Rene Harder <rehar at saweb.de>

Modified: trunk/gta02-core/docs/ecn/ecn0033.txt
===================================================================
--- trunk/gta02-core/docs/ecn/ecn0033.txt	2009-08-26 21:37:47 UTC (rev 5547)
+++ trunk/gta02-core/docs/ecn/ecn0033.txt	2009-08-26 21:39:54 UTC (rev 5548)
@@ -6,14 +6,18 @@
 To follow Wolfson's recommendation we will change all line input/output 
 coupling capacitors to 1uF.
 
-Replace the following capacitors with 1uF (CM105X5R105M16AT):
+Replace the following capacitors with 1uF/6.3V SMD-0402 :
 - C4304 and C4303 (MIC input)
-- C3007 and C3008 (GSM modem input)
+- C3007 and C3006 (GSM modem input)
 - C3018 and C3011 (GSM modem output)
-- C3016 (headset MIC)
+- C3016 and C4406 (headset MIC)
 
 
 [1] http://www.wolfsonmicro.com/uploads/documents/en/WM8753.pdf (p. 88)
 
+Todo:
+find a suitable and easy to source capacitor e.g. TDK C1005X5R0J105K (Digi-Key)
+or AVX 04026D105KAT2A (Digi-Key & Farnell) 
 
+
 Author: Rene Harder <rehar at saweb.de>




More information about the commitlog mailing list