ISL12022MIBZ-T7A Datasheet, PDF (17/31 Pages) Intersil Corporation – Low Power RTC with Battery Backed SRAM, Integrated ±5ppm Temperature Compensation and Auto Daylight Saving

ISL12022M
VB85Tp2
0
0
0
0
1
1
1
TABLE 8. VB85T ALARM LEVEL
VB85Tp1
VB85Tp0
BATTERY ALARM TRIP
LEVEL
(V)
0
0
2.125
0
1
2.295
1
0
2.550
1
1
2.805
0
0
3.060
0
1
4.250
1
0
4.675
BATTERY LEVEL MONITOR TRIP BITS (VB75TP <2:0>)
Three bits select the second alarm (75% of Nominal V_BAT) level for
the battery voltage monitor. There are total of 7 levels that could be
selected for the second alarm. Any of the of levels could be selected
as the second alarm with no reference as to nominal Battery voltage
level. See Table 9.
TABLE 9. BATTERY LEVEL MONITOR TRIP BITS (VB75TP <2:0>)
VB75Tp2
VB75Tp1
VB75Tp0
BATTERY ALARM TRIP
LEVEL
(V)
0
0
0
1.875
0
0
1
2.025
0
1
0
2.250
0
1
1
2.475
1
0
0
2.700
1
0
1
3.750
1
1
0
4.125
Initial AT and DT Setting Register (ITRO)
These bits are used to trim the initial error (at room temperature)
of the crystal. Both Digital Trimming (DT) and Analog Trimming
(AT) methods are available. The digital trimming uses clock pulse
skipping and insertion for frequency adjustment. Analog
trimming uses load capacitance adjustment to pull the oscillator
frequency. A range of +62.5ppm to -61.5ppm is possible with
combined digital and analog trimming.
Initial values for the ITR0 register are preset internally and recalled
to RAM registers on power-up. These values are pre-set in device
production and are READ-ONLY. They cannot be overwritten by the
user. If an application requires adjustment of the IATR bits outside
the preset values, the user should contact Intersil.
AGING AND INITIAL TRIM DIGITAL TRIMMING BITS
(IDTR0<1:0>)
These bits allow ±30.5ppm initial trimming range for the crystal
frequency. This is meant to be a coarse adjustment if the range
needed is outside that of the IATR control. See Table 10. The
IDTR0 register should only be changed while the TSE (Temp
Sense Enable) bit is “0”.
The ISL12022M has a preset Initial Digital Trimming value
corresponding to the crystal in the module. This value is recalled
on initial power-up and is READ-ONLY. It cannot be overwritten by
the user.
IDTR01
0
0
1
1
TABLE 10. IDTR0 TRIMMING RANGE
IDTR00
TRIMMING RANGE
0
Default/Disabled
1
+30.5ppm
0
0ppm
1
-30.5ppm
AGING AND INITIAL ANALOG TRIMMING BITS
(IATR0<5:0>)
The Initial Analog Trimming Register allows +32ppm to -31ppm
adjustment in 1ppm/bit increments. This enables fine frequency
adjustment for trimming initial crystal accuracy error or to
correct for aging drift.
The ISL12022M has a preset Initial Analog Trimming value
corresponding to the crystal in the module. This value is recalled on
initial power-up, is preset in device production and is READ-ONLY. It
cannot be overwritten by the user.
TABLE 11. INITIAL AT AND DT SETTING REGISTER
ADDR 7
6
5
4
3
2
1
0
0Bh IDTR01 IDTR00 IATR05 IATR04 IATR03 IATR02 IATR01 IATR00
TABLE 12. IATRO TRIMMING RANGE
TRIMMING
IATR05 IATR04 IATR03 IATR02 IATR01 IATR00 RANGE
0
0
0
0
0
0
+32
0
0
0
0
0
1
+31
0
0
0
0
1
0
+30
0
0
0
0
1
1
+29
0
0
0
1
0
0
+28
0
0
0
1
0
1
+27
0
0
0
1
1
0
+26
0
0
0
1
1
1
+25
0
0
1
0
0
0
+24
0
0
1
0
0
1
+23
0
0
1
0
1
0
+22
0
0
1
0
1
1
+21
0
0
1
1
0
0
+20
0
0
1
1
0
1
+19
0
0
1
1
1
0
+18
0
0
1
1
1
1
+17
0
1
0
0
0
0
+16
0
1
0
0
0
1
+15
0
1
0
0
1
0
+14
17
FN6668.9
June 20, 2012