DS12885SN+ Maxim Integrated Products, DS12885SN+ Datasheet - Page 10

• Manufacturer Part Number: DS12885SN+
• Description: IC RTC W/RAM 128 BYTE IND 24SOIC
• Manufacturer: Maxim Integrated Products
• Type: Clock/Calendar/NVSRAMr

Specifications of DS12885SN+

• Memory Size: 114B
• Time Format: HH:MM:SS (12/24 hr)
• Date Format: YY-MM-DD-dd
• Interface: Parallel
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Real-Time Clocks
10
PDIP
SO,
19
20
21
23
24
____________________________________________________________________
DS12C887A)
(DS12887A/
EDIP
21
19
23
24
—
PIN
PLCC
25
23
24
27
28
TQFP
21
22
24
26
28
NAME
RCLR
V
SQW
V
IRQ
BAT
CC
Active-Low Interrupt Request Output. The IRQ pin is an active-low output of the
device that can be used as an interrupt input to a processor. The IRQ output
remains low as long as the status bit causing the interrupt is present and the
corresponding interrupt-enable bit is set. The processor program normally
reads the C register to clear the IRQ pin. The RESET pin also clears pending
interrupts. When no interrupt conditions are present, the IRQ level is in the high-
impedance state. Multiple interrupting devices can be connected to an IRQ
bus, provided that they are all open drain. The IRQ pin is an open-drain output
and requires an external pullup resistor to V
Connection for a Primary Battery. (DS12885 Only.) Battery voltage must be held
between the minimum and maximum limits for proper operation. If a backup
supply is not supplied, V
the V
prevent proper operation. UL recognized to ensure against reverse charging
when used with a lithium battery.
Active-Low RAM Clear. The RCLR pin is used to clear (set to logic 1) all the
general-purpose RAM, but does not affect the RAM associated with the RTC. To
clear the RAM, RCLR must be forced to an input logic 0 during battery-backup
mode when V
through a human interface (shorting to ground manually or by a switch) and not
to be driven with external buffers. This pin is internally pulled up. Do not use an
external pullup resistor on this pin.
Square-Wave Output. The SQW pin can output a signal from one of 13 taps
provided by the 15 internal divider stages of the RTC. The frequency of the
SQW pin can be changed by programming Register A, as shown in Table 1.
The SQW signal can be turned on and off using the SQWE bit in Register B. The
SQW signal is not available when V
DC Power Pin for Primary Power Supply. When V
limits, the device is fully accessible and data can be written and read. When
V
CC
is below V
BAT
pin. Diodes in series between the V
CC
PF
is not applied. The RCLR function is designed to be used
reads and writes are inhibited.
BAT
must be grounded. Connect the battery directly to
Pin Description (continued)
FUNCTION
CC
is less than V
CC
BAT
.
CC
pin and the battery may
PF
is applied within normal
.