From 9bfe68963e4c1be20c1249887a6b7a3998e434d1 Mon Sep 17 00:00:00 2001 From: Bdale Garbee Date: Sat, 27 Feb 2010 15:44:56 -0700 Subject: [PATCH] more notes --- Notebook | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) 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. + -- 2.30.2