DS1341_12 Datasheet, PDF (15/16 Pages) Maxim Integrated Products – Low-Current I2C RTCs for High-ESR Crystals

Low-Current I²C RTCs for High-ESR Crystals
reads data with ACK or NACK as applicable, and
generates a STOP condition. See Figure 6 for a read
example using the repeated START condition to
specify the starting memory location.
Reading Multiple Bytes from a Slave: The read
operation can be used to read multiple bytes with a
single transfer. When reading bytes from the slave,
the master simply ACKs the data byte if it desires to
read another byte before terminating the transaction.
After the master reads the last byte it must NACK to
indicate the end of the transfer and then it generates
a STOP condition.
Bus Timeout
To avoid an unintended I²C interface timeout, SCL
should not be held low longer than tTIMEOUTMIN. The
I²C interface is in the reset state and can receive a
new START condition when SCL is held low for at least
tTIMEOUTMAX. When the device detects this condition,
SDA is released and allowed to be pulled high by the
external pullup resistor. For the timeout function to work,
the oscillator must be enabled and running.
Applications Information
Power-Supply Decoupling
To achieve the best results when using the DS1341/
DS1342, decouple the VCC power supply with a 0.01FF
and/or 0.1FF capacitor. Use a high-quality, ceramic, sur-
face-mount capacitor if possible. Surface-mount compo-
nents minimize lead inductance, which improves perfor-
mance, and ceramic capacitors tend to have adequate
high-frequency response for decoupling applications.
Using Open-Drain Outputs
The CLKIN/INTA output is open drain and, therefore,
requires an external pullup resistor to realize a logic-high
output level.
SDA and SCL Pullup Resistors
SDA is an open-drain output and requires an external
pullup resistor to realize a logic-high level.
Because the DS1341/DS1342 do not use clock cycle
stretching, a master using either an open-drain output
with a pullup resistor or CMOS output driver (push-pull)
could be used for SCL.
Chip Information
SUBSTRATE CONNECTED TO GROUND
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maxim-ic.com/packages. Note that a
“+”, “#”, or “-” in the package code indicates RoHS status only.
Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
PACKAGE
TYPE
8 FSOP
8 TDFN-EP
PACKAGE
CODE
U8+1
T833+2
OUTLINE
NO.
21-0036
21-0137
LAND
PATTERN NO.
90-0092
90-0059
15