Datasheet

DC and AC parameters M41T94
30/41
Table 13. DC characteristics
Symb. Parameter Test condition
(1)
Min Typ Max Unit
I
BAT
Battery current OSC on
T
A
= 25°C, V
CC
= 0 V,
V
BAT
= 3 V
400 500 nA
Battery current OSC off 50 nA
I
CC1
Supply current f = 2 MHz 2 mA
I
CC2
Supply current (standby) SCL, SDI = V
CC
– 0.3 V 1.4 mA
I
LI
(2)
Input leakage current 0 V ≤ V
IN
≤ V
CC
±1 µA
I
LO
(3)
Output leakage current 0 V ≤ V
OUT
≤ V
CC
±1 µA
V
IH
Input high voltage 0.7V
CC
V
CC
+ 0.3 V
V
IL
Input low voltage –0.3 0.3V
CC
V
V
BAT
Battery voltage 2.5 3.5
(4)
V
V
OH
Output high voltage
(5)
I
OH
= –1.0 mA 2.4 V
V
OL
Output low voltage
(5)
I
OL
= 3.0 mA 0.4
V
Output low voltage (open drain)
(6)
I
OL
= 10 mA 0.4
Pull-up supply voltage (open drain) RST
, IRQ/FT/OUT 5.5 V
V
PFD
Power fail deselect (THS = V
CC
) 4.20 4.40 4.50
V
Power fail deselect (THS = V
SS
) 2.55 2.60 2.70
V
SO
Battery backup switchover 2.5 V
1. Valid for ambient operating temperature: T
A
= –40 to 85°C; V
CC
= 2.7 to 5.5 V (except where noted).
2. RSTIN1
and RSTIN2 internally pulled up to V
CC
through 100 KΩ resistor. WDI internally pulled-down to V
SS
through
100 KΩ resistor.
3. Outputs deselected.
4. For rechargeable back-up, V
BAT
(max) may be considered V
CC
.
5. For SQW pin (CMOS).
6. For IRQ
/FT/OUT, RST pins (open drain): if pulled up to supply other than V
CC
, this supply must be equal to, or less than
3.0 V when V
CC
= 0 V (during battery backup mode).
Table 14. Crystal electrical characteristics (externally supplied)
Symbol Parameter
(1)(2)
Typ Min Max Unit
f
0
Resonant frequency 32.768 kHz
R
S
Series resistance 50 kΩ
C
L
Load capacitance 12.5 pF
1. Load capacitors are integrated within the M41T94. 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. These characteristics are
externally supplied.
2. 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. For contact information on this crystal type,
see Section 10: References on page 39.