AT91SAM7L-STK Rev. A Starter Kit User Guide
6-1
6409A–ATARM–30-Jun-08
Section 6
Errata
6.1
Q1 Footprint Incorrect
Transistor Q1 is incorrectly connected. The schematic is right but the PCB connections of pins S and D
are swapped => the protection diode is polarized forward (permanent current flow across the bridge) and
the MOS is not operating properly (non accurate battery level measurement).
Problem Fix/Workaround
Remove Q1 in order to avoid the parasitic 150
µ
A battery drain. If battery measurement is really manda-
tory for some applications, Q1 has to be removed and soldered bottom up, taking care to apply the
correct polarity. Additionally, a 100 K
Ω
pull-up resistor is needed across gate and source.
6.2
MAX3318 Control Pull-ups
The default configuration of the MAX3318 is ON. This leads to extra power consumption discharging the
batteries when the AT91SAM7L128 enters OFF mode (or does not even drive PC7 and PC12 to put the
MAX3318 in OFF mode).
Problem Fix/Workaround
Remove R1, R2 and R3 and add a 10M
Ω
pull-down resistor on PC7. This allows to Force OFF the
MAX3318 when the AT91SAM7L128 enters OFF mode and to turn it on when the AT91SAM7L128
wakes up. The user can save power consumption by driving PC7 connected to the FORCEOFF pin of
the MAX3318.
