MAX6909EO33 Maxim Integrated, MAX6909EO33 Datasheet - Page 23

• Manufacturer Part Number: MAX6909EO33
• Description: Real Time Clock
• Manufacturer: Maxim Integrated
• Series: MAX6909, MAX6910r

Specifications of MAX6909EO33

• Function: Clock, Calendar, Watchdog Timekeeper, NV SRAM Control
• Rtc Bus Interface: Serial
• Time Format: HH
• Rtc Memory Size: 31 B
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 3 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Package / Case: QSOP-20

Figure 12. Chip-Enable Timing
Figure 13. Chip-Enable Timing Including MR
The MAX6909/MAX6910 PFI is compared to an internal
reference. If the PFI voltage is less than the power-fail
threshold (V
parator is intended for use as an undervoltage detector
to signal a failing power supply and can monitor either
positive or negative supplies using a voltage-divider to
PFI (Figure 26). However, the comparator does not
need to be dedicated to this function because it is
completely separate from the rest of the circuitry.
Any time V
the state of PFI. Any time V
active low (during the reset timeout period), PFO is
forced high, regardless of the state of PFI. If the com-
parator is unused, connect PFI to V
floating. Figure 15 shows PFI and PFO timing.
V
CE OUT
RESET
CE IN
CE OUT
RESET
CC
CE IN
MR
V
BATT
CC
PFT
< V
I
), PFO goes low. The power-fail com-
V
RST
2
RST
______________________________________________________________________________________
t
t
RP
RP
C-Compatible Real-Time Clocks with µP
, PFO is forced low, regardless of
Power-Fail Comparator
CC
t
RCE
Supervisor and NV RAM Controller
> V
t
t
RST
CC
RP
RP
V
RST
and leave PFO
and RESET is
t
RCE
Figure 14. CE Propagation-Delay Test Circuit
Figure 15. PFI and
V
V
RST
BATT
*C
RESET
PFO
PFI
V
CC
L
INCLUDES LOAD CAPACITANCE AND SCOPE PROBE CAPACITANCE.
V
RST
50Ω
V
CC
t
RST
25Ω EQUIVALENT
SOURCE IMPEDANCE
50Ω CABLE
PFO Timing
3.6V
50Ω
V
BATT
CE IN
V
PFT
RST
MAX6909/
MAX6910
VCC
GND
V
CC
CE OUT
V
BATT
50pF
C
L
*
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