Datasheet

DC and AC parameters M41T81
22/29 Doc ID 7529 Rev 10
Figure 15. Power down/up mode AC waveforms
Table 9. DC characteristics
Sym Parameter Test condition
(1)
1. Valid for ambient operating temperature: T
A
= –40 to 85°C; V
CC
= 2.0 to 5.5 V (except where noted).
Min Typ Max Unit
I
LI
Input leakage current 0V ≤ V
IN
≤ V
CC
±1 µA
I
LO
Output leakage current 0V ≤ V
OUT
≤ V
CC
±1 µA
I
CC1
Supply current Switch freq = 400 kHz 400 µA
I
CC2
Supply current (standby) SCL,SDA = V
CC
– 0.3V 100 µA
V
IL
Input low voltage –0.3 0.3V
CC
V
V
IH
Input high voltage 0.7V
CC
V
CC
+ 0.3 V
V
OL
Output low voltage I
OL
= 3.0 mA 0.4 V
Output low voltage (open
drain)
(2)
2. For IRQ/FT/OUT/SQW pin (open drain)
I
OL
= 10 mA 0.4 V
Pull-up supply voltage
(open drain)
IRQ
/OUT/FT/SQW 5.5 V
V
BAT
(3)
3. STMicroelectronics recommends the RAYOVAC BR1225 or BR1632 (or equivalent) as the battery supply.
Battery supply voltage 2.5
(4)
4. After switchover (V
SO
), V
BAT
(min) can be 2.0 V for crystal with R
S
= 40 kΩ.
33.5
(5)
5. For rechargeable backup, V
BAT
(max) may be considered V
CC
.
V
I
BAT
Battery supply current
T
A
= 25 °C, V
CC
= 0 V
oscillator on, V
BAT
= 3 V
0.6 1 µA
Table 10. Crystal electrical characteristics
Sym Parameter
(1)(2)
1. Externally supplied. STMicroelectronics recommends the KDS DT-38: 1TA/1TC252E127, Tuning Fork
Type (thru-hole) or the DMX-26S: 1TJS125FH2A212, (SMD) quartz crystal for industrial temperature
operations. KDS can be contacted at [e-mail] or http://www.kdsj.co.jp for further information on
this crystal type.
2. Load capacitors are integrated within the M41T81. Circuit board layout considerations for the 32.768 kHz
crystal of minimum trace lengths and isolation from RF generating signals should be taken into account.
Min Typ Max Units
f
O
Resonant frequency - 32.768 kHz
R
S
Series resistance - 60 kΩ
C
L
Load capacitance - 12.5 pF
AI00596
V
CC
trec
tPD
V
SO
SDA
SCL
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