ISL1209IU10Z Intersil, ISL1209IU10Z Datasheet - Page 15

• Manufacturer Part Number: ISL1209IU10Z
• Description: IC RTC LP BATT BACK SRAM 10MSOP
• Manufacturer: Intersil
• Type: Clock/Calendar/NVSRAMr

Specifications of ISL1209IU10Z

• Memory Size: 2B
• Time Format: HH:MM:SS (12/24 hr)
• Date Format: YY-MM-DD-dd
• Interface: I²C, 2-Wire Serial
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

EVENT INPUT TIME BASE HYSTERESIS SELECTION
BITS (EHYS<1:0>)
These two bits select the time base hysteresis of the EVIN
pin to filter bouncing or noise of external event detection
circuits. The time filter can be set between 0 to 31.25 ms.
NOTE: In order to use time-based hysteresis, the sampling mode
must be enabled.
EVENT DETECT ENABLE BIT (EVEN)
This bit enables/disables the Event Detect function of the
ISL1209. When this bit is set to “1”, the Event Detect is
active. When this bit is cleared to “0”, the Event Detect is
disabled.
RTC HALT ON EVENT DETECT BIT (RTCHLT)
This bit sets the RTC registers to continue or halt counting
upon an Event Detect triggered by the EV pin. The time
keeping function will cease when RTCHLT is set to “1”, the
RTC will discontinue incrementing if an event is detected.
Counting will resume when there is a valid write to the to the
RTC registers (i.e. time set). The RTCHLT is cleared to “0”
after the write to the RTC registers.
Note: This function requires that the event detection is
enabled (see EVEN bit).
EVENT OUTPUT IN BATTERY MODE ENABLE BIT
(EVBATB)
This bit enables/disables the EVDET pin during battery
backup mode (i.e. V
is set to “1”, the Event Detect Output is disabled in battery
backup mode. When the EVBATB is cleared to “0”, the Event
Detect output is enabled in battery backup mode.This
feature can be used to save power during battery mode.
EVENT CURRENT SOURCE ENABLE BIT (EVIENB)
This bit enables/disables the internal pullup current source
used for the EVIN pin. When the EVIENB bit is set to “1”, the
pullup current source is always disabled. When the EVIENB
bit is cleared to “0”, the pullup current source is enabled
(current source is approximately 1µA).
Analog Trimming Register
ANALOG TRIMMING REGISTER (ATR<5:0>)
Six analog trimming bits, ATR0 to ATR5, are provided in
order to adjust the on-chip load capacitance value for
frequency compensation of the RTC. Each bit has a different
weight for capacitance adjustment. For example, using a
EHYS1
0
0
1
1
BAT
EHYS0
0
1
0
1
pin supply ON). When the EVBATB
TABLE 11.
15
Time Base Hysteresis
0 (pullup always on)
15.625ms
31.25ms
3.9ms
ISL1209
Citizen CFS-206 crystal with different ATR bit combinations
provides an estimated ppm adjustment range from -34 to
+80ppm to the nominal frequency compensation. The
combination of analog and digital trimming can give up to -94
to +140ppm of total adjustment.
The effective on-chip series load capacitance, C
ranges from 4.5pF to 20.25pF with a mid-scale value of
12.5pF (default). C
controlled capacitors, C
and X2 pins to ground (see Figure 11). The value of C
C
The effective series load capacitance is the combination of
C
For example, C
C
20.25pF. The entire range for the series combination of load
capacitance goes from 4.5pF to 20.25pF in 0.25pF steps.
Note that these are typical values.
BATTERY MODE ATR SELECTION (BMATR <1:0>)
Since the accuracy of the crystal oscillator is dependent on
the V
to adjust the capacitance between V
device switches between power sources.
C
C
C
X2
X1
LOAD
X
LOAD
LOAD
=
is given by the following formula:
and C
DD
(
16 b5
(ATR=100000) = 4.5pF, and C
=
=
/V
⋅
⎛
⎝
---------------------------------- -
⎛
⎝
BAT
X2
---------- -
C
16 b5
---------------------------------------------------------------------------------------------------------------------------- -
1
X1
+
:
⋅
8 b4
X1
X2
operation, the ISL1209 provides the capability
1
+
FIGURE 11. DIAGRAM OF ATR
LOAD
⋅
---------- -
C
+
1
8 b4
X2
LOAD
+
⋅
4 b3
C
C
⎞
⎠
(ATR=00000) = 12.5pF,
X1
X2
⋅
+
X1
4 b3
is changed via two digitally
+
⋅
and C
2 b2
⋅
+
2 b2
2
+
⋅
X2
1 b1
⋅
, connected from the X1
Oscillator
+
DD
Crystal
1 b1
LOAD
+
⋅
and V
0.5 b0
+
⋅
(ATR=011111) =
0.5 b0
BAT
+
⋅
9
LOAD
October 17, 2006
)pF
when the
+
9
⎞ pF
⎠
X1
,
FN6109.4
and