DS1685S-3 Maxim Integrated Products, DS1685S-3 Datasheet - Page 17

• Manufacturer Part Number: DS1685S-3
• Description: Real Time Clock
• Manufacturer: Maxim Integrated Products

Specifications of DS1685S-3

• Function: Clock, Calendar, Alarm
• Rtc Memory Size: 242 B
• Supply Voltage (max): 3.7 V
• Supply Voltage (min): 2.7 V
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Rtc Bus Interface: Multiplexed
• Package / Case: SOIC-24
• Time Format: HH:MM:SS, Binary
• Date Format: DW:DM:M:Y, Binary
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 4. Update-Ended And Periodic-Interrupt Relationship
EXTENDED FUNCTIONS
The extended functions provided by the DS1685/DS1687 that are new to the RAMified RTC family are accessed by
a software-controlled bank-switching scheme, as illustrated in Figure 5. In bank 0, the clock/calendar registers and
50 bytes of user RAM are in the same locations as for the DS1287. As a result, existing routines implemented
within BIOS, DOS, or application software packages can gain access to the DS1685/DS1687 clock registers with
no changes. Also in bank 0, an extra 64 bytes of RAM are provided at addresses just above the original locations
for a total of 114 directly addressable bytes of user RAM.
UIP
PF
UF
t
t
PI
BUC
= PERIODIC INTERRUPT TIME INTERNAL PER TABLE 3.
= DELAY BEFORE UPDATE CYCLE = 244s.
t
BUC
17 of 34
1 second
t
PI
t
PI/2
DS1685/DS1687 3V/5V Real-Time Clocks
t
PI/2