Extremely Accurate I
2
C-Integrated
RTC/TCXO/Crystal
Maxim Integrated 19
DS3231
Revision History
REVISION
NUMBER
REVISION
DATE
DESCRIPTION
PAGES
CHANGED
0 1/05 Initial release. —
Changed Digital Temp Sensor Output from ±2°C to ±3°C. 1, 3
Updated Typical Operating Circuit. 1
Changed T
A
= -40°C to +85°C to T
A
= T
MIN
to T
MAX
. 2, 3, 4
1 2/05
Updated Block Diagram. 8
Added “UL Recognized” to Features; added lead-free packages and removed S from
top mark info in Ordering Information table; added ground connections to the N.C. pin
in the Typical Operating Circuit.
1
Added “noncondensing” to operating temperature range; changed V
PF
MIN from 2.35V
to 2.45V.
2
Added aging offset specification. 3
Relabeled TOC4. 7
Added arrow showing input on X1 in the Block Diagram. 8
Updated pin descriptions for V
CC
and V
BAT
. 9
Added the I
2
C Interface section. 10
Figure 1: Added sign bit to aging and temperature registers; added MSB and LSB. 11
Corrected title for rate select bits frequency table. 13
Added note that frequency stability over temperature spec is with aging offset register
= 00h; changed bit 7 from Data to Sign (Crystal Aging Offset Register).
14
Changed bit 7 from Data to Sign (Temperature Register); correct pin definitions in I
2
C
Serial Data Bus section.
15
2 6/05
Modified the Handing, PC Board Layout, and Assembly section to refer to
J-STD-020 for reflow profiles for lead-free and leaded packages.
17
3 11/05 Changed lead-free packages to RoHS-compliant packages. 1
Changed RST and UL bullets in Features. 1
Changed EC condition “V
CC
> V
BAT
” to “V
CC
= Active Supply (see Table 1).” 2, 3
Modified Note 12 to correct t
REC
operation. 6
Added various conditions text to TOCs 1, 2, and 3. 7
Added text to pin descriptions for 32kHz, V
CC
, and RST. 9
Table 1: Changed column heading “Powered By” to “Active Supply”; changed
“applied” to “exceeds V
PF
” in the Power Control section.
10
Indicated BBSQW applies to both SQW and interrupts; simplified temp convert
description (bit 5); added “output” to INT/SQW (bit 2).
13
4 10/06
Changed the Crystal Aging section to the Aging Offset section; changed “this bit
indicates” to “this bit controls” for the enable 32kHz output bit.
14
Added Warning note to EC table notes; updated Note 12. 6
Updated the Typical Operating Characteristics graphs. 7
In the Power Control section, added information about the POR state of the time and
date registers; in the Real-Time Clock section, added to the description of the RST
function.
10
5 4/08
In Figure 1, corrected the months date range for 04h from 00–31 to 01–31. 11
