M4T28-BR12SH ST Microelectronics, M4T28-BR12SH Datasheet - Page 23

• Manufacturer Part Number: M4T28-BR12SH
• Description: TIMEKEEPER SNAPHAT Battery & Crystal
• Manufacturer: ST Microelectronics

Power-on Reset
The M41ST85Y/W continuously monitors V
When V
the RST pulls low (open drain) and remains low on
power-up for t
The RST pin is an open drain output and an appro-
priate pull-up resistor should be chosen to control
rise time.
Figure 20. RSTIN1 & RSTIN2 Timing Waveforms
Note: With pull-up resistor
Table 11. Reset AC Characteristics
Note: 1. Valid for Ambient Operating Temperature: T
2. Pulse width less than 50ns will result in no RESET (for noise immunity).
3. Pulse width less than 20ms will result in no RESET (for noise immunity).
4. Programmable (see Table 12, page 25).
t
t
t
t
Symbol
R1HRH
R2HRH
RLRH1
RLRH2
CC
RSTIN1
RSTIN2
RST
falls to the power fail detect trip point,
(2)
(3)
(4)
(4)
(1)
REC
after V
RSTIN1 Low to RSTIN1 High
RSTIN2 Low to RSTIN2 High
RSTIN1 High to RST High
RSTIN2 High to RST High
CC
passes V
Parameter
tRLRH1
tR1HRH
PFD
A
= –40 to 85°C; V
(1)
(max).
CC
.
tRLRH2
CC
Reset Inputs (RSTIN1 & RSTIN2)
The M41ST85Y/W provides two independent in-
puts which can generate an output reset. The du-
ration and function of these resets is identical to a
reset generated by a power cycle. Table 11 and
Figure 20 illustrate the AC reset characteristics of
this function. Pulses shorter than t
t
and RSTIN2 are each internally pulled up to V
through a 100k
RLRH2
= 4.5 to 5.5V or 2.7 to 3.6V (except where noted).
will not generate a reset condition. RSTIN1
Min
200
100
40
40
tR2HRH
resistor.
M41ST85Y, M41ST85W
Max
200
200
AI03665
RLRH1
Unit
ms
ms
ms
ns
23/33
and
CC