From: Bdale Garbee <bdale@gag.com>
Date: Sat, 27 Feb 2010 22:44:56 +0000 (-0700)
Subject: more notes
X-Git-Tag: quote-v1.0~6
X-Git-Url: https://git.gag.com/?p=hw%2Ftelemetrum;a=commitdiff_plain;h=9bfe68963e4c1be20c1249887a6b7a3998e434d1

more notes
---

diff --git a/Notebook b/Notebook
index 3542ca4..82cd96a 100644
--- a/Notebook
+++ b/Notebook
@@ -153,3 +153,43 @@
 	AT45DB161D-SU-ND in SOIC-8 for $2.26 each
   appears to compare favorably against $4.40 for current 128kx8 part
   minor concern about write power, but probably red herring
+
+2010.02.08
+- looking at LiPo charger alternatives
+
+	MAX8808		DFN8, not carried by DK
+	MAX8814		DFN8, not carried by DK
+
+	LTC4095		DFN8, LTC4095EDC#TRMPBFCT-ND 2.91 2.34@100
+		950mA, resistor current set, rate limit input, suspend input,
+		NTC thermal control option, smart CHRG led with 4 states
+	LTC4065		DFN6, LTC4065EDC#TRMPBFCT-ND 2.77 2.23@100
+		750mA, resistor current set, CHRG led, enable input
+	LTC4065A	DFN6, LTC4065AEDC#TRMPBFCT-ND 2.77 2.23@100
+		750mA, resistor current set, CHRG led, supply present out
+		
+	MCP73811	SOT23-5, MCP73811T-420I/OTCT-ND 0.63@1 0.39@100
+		input selects 85 vs 450mA charge current
+
+	MCP73837	DFN10, MCP73837T-FCI/MFCT-ND 1.37@1 0.85@100
+		usb rate select, power good output, dual inputs, dual status
+
+	LX2206		DFN10, LX2206CT-ND 2.68@1 2.01@100
+		rate select, power good output... needs more passives?
+
+	LM3658		DFN10, 
+		dual input, dual rate, two status outputs .. not obvious win
+
+	MCP73855	DFN10, MCP73855T-I/MFCT-ND 1.85@1 1.18@100
+		see Microchip app note 971
+
+
+  Talking to Keith, there's no reason we couldn't use an 8-pin PIC to augment
+  a standalone LiPo charger, implementing a timer after vusb application 
+  before switching the regulator to high current, to allow the cc1111 time to
+  finish the USB bus negotiation phase.  We could also monitor various state
+  bits and multiplex signaling onto one LED.  A combo like the MCP73837 plus
+  a PIC10F206 or 220 would net under $1.50 at 100 pieces and be pretty 
+  powerful.  Since the PIC has avilable weak pull-ups on the gpio lines, the
+  open-drain state outputs from the regulator don't need resistors to be read.
+