MCP7940NT-I/MS Microchip Technology, MCP7940NT-I/MS Datasheet - Page 13

• Manufacturer Part Number: MCP7940NT-I/MS
• Description: Real Time Clock I2C GP RTCC 64B SRAM
• Manufacturer: Microchip Technology
• Series: -r
• Type: Clock/Calendarr

Specifications of MCP7940NT-I/MS

• Features: Alarm, Leap Year, SRAM
• Memory Size: 64B
• Time Format: HH:MM:SS (12/24 hr)
• Date Format: YY-MM-DD-dd
• Interface: I²C
• Voltage - Supply: 1.8 V ~ 5.5 V
• Voltage - Supply, Battery: 1.3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

4.2.2
Pin 7 is a multi-function pin and supports the following
functions:
• Use of the OUT bit in the Control register for
• Alarm Outputs – Available in V
• FOUT mode – driven from a FOSC divider – Not
The internal control logic for the MFP is connected to
the switched internal supply bus, this allows operation
in V
operates in V
4.2.3
If the V
should be connected to GND. A low-value series
resistor is recommended between the external battery
and the V
The V
falls below 1.5V the system will continue to operate
the RTCC and SRAM using the V
following conditions apply:
TABLE 4-2:
4.2.4
The MCP7940N has been designed to operate with a
standard 32 kHz crystal. Devices with a specified load
capacitance of either 12pF or 6pF can be used. The
end user should fully validate the chosen crystal across
all the expected design parameters of the system to
ensure correct operation.
The following crystals have been tested and shown to
work with the MCP7940N:
• CM200S 12pF surface mount crystals from
• ECS-.327 12pF surface mount crystals from ECS
• CFS206 12pF leaded crystals from Citizen
This is not a definitive list and all crystals should be
tested in the target application across all temperature,
voltage and other significant environmental conditions.
4.2.5
The MCP7940N family of RTCC devices feature a
power-fail time-stamp feature. This feature will save
the time at which V
use this feature, a V
the oscillator must also be running.
 2011 Microchip Technology Inc.
V
V
V
single bit I/O
available in V
CC
CC
CC
Citizen
INC
BAT
< V
> V
> V
BAT
mode. The Alarm Output is the only mode that
BAT
Condition
TRIP
TRIP
TRIP
BAT
Supply
point is defined as 1.5V typical. When V
MFP
V
CRYSTAL SPECS
POWER-FAIL TIME-STAMP
feature is not being used, the V
, V
, V
, V
BAT
BAT
pin.
BAT
CC
CC
CC
mode, other modes are suspended.
< V
< V
> V
mode
CC
BAT
BAT
BAT
BAT
crosses the V
supply must be present and
Read/Write
Access
BAT
Yes
Yes
No
mode
BAT
TRIP
supply. The
voltage. To
Powered
V
BAT
V
V
By
BAT
CC
CC
pin
DD
There are two separate sets of registers that are used
to record this information:
• The first set located at 0x18h through 0x1Bh are
• The second set of registers, located at 0x1Ch
The power-fail time-stamp registers are cleared when
the V
loaded at the time when V
operates on the V
bit 4) bit is also set at this time.
through 0x1Fh, are loaded at the time when V
is restored and the RTCC switches to V
BAT
bit is cleared in software.
BAT
. The V
MCP7940N
CC
BAT
fails and the RTCC
(register 0x03h
DS25010A-page 13
CC
.
CC