more notes

diff --git a/Notebook b/Notebook
index 3542ca466275d10827d419fcf0032ee0a1c6a6af..82cd96a59973becf65f792458cca71a953c62152 100644 (file)
--- 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.
+