R
EM MICROELECTRONIC - MARIN SA
V3025
Very Low Power 8-Bit 32 kHz RTC Module with Digital
Trimming, User RAM and Battery Switch-over
Description
Features
ꢀ Built-in quartz with digital trimming and
temperature compensation facilities
The V3025 is a low power CMOS real time clock with an
integrated battery switch-over. The standby current is
typically 2.5 µA and the access time is 50 ns. The
interface is a multiplexed address and data 8 bits bus.
Multiplexing of address and data is handled by the input
ꢀ INTEL and MOTOROLA interface compatibility
ꢀ 15 ns typical access time at 5.0V
ꢀ 1.2 µA typical standby current at 3.0V
ꢀ Wide supply voltage range, 2.0 ≤ VDD ≤ 5.5V
ꢀ Integrated battery switch-over
ꢀ Battery voltage range, 2.0 ≤ VBAT ≤ 4.0V
ꢀ No busy state
line A /D. There are no busy flags in the V3025, internal
time update cycles are invisible to the user's software.
Time data can be read from the V3025 in 12 or 24 hour
data formats. An external signal puts the V3025 in
standby mode. Even in standby, the V3025 pulls the IRQ
pin active low on an internal alarm interrupt. Calendar
functions include leap year correction and week number
calculation. The V3025 can be synchronized to an
external 50 Hz signal or to the nearest second or minute.
The integrated battery switch-over supply the real time
ꢀ No external components required
ꢀ BCD format
ꢀ Frequency measurements
ꢀ Time set lock mode
ꢀ Week number calculation
clock part by VDD as long as VDD is higher than VBAT
.
ꢀ Clock counts up to 99 years
When VDD decreases under VBAT, the output PFO comes
active and the real clock is supplied by the battery or the
supercap.
ꢀ Leap year correction
ꢀ 12 or 24 hour data format
ꢀ Output programmable interrupts
ꢀ Alarm interrupt, programmable up to one month
ꢀ Timer interrupt, programmable up to 24 hours
ꢀ Time to 1/100 of a second
Applications
ꢀ Industrial controllers
ꢀ Alarm systems with periodic wake up
ꢀ PABX and telephone systems
ꢀ Point of sale terminals
ꢀ Automotive electronics
ꢀ Personal computers
ꢀ To external time reference synchronisation
ꢀ 50 Hz or nearest s/min synchronisation
ꢀ Power fail input PFI
ꢀ Power fail output or Reset output PFO
ꢀ Tri-state bus capability when power fail (PFI = 0)
ꢀ User RAM
ꢀ Temperature range -40 to +85°C
ꢀ Package SO28
Typical Operating Configuration
Pin Assignment
SO28
VBAT
AD7
AD6
AD5
AD4
RD
SYNC
PFI
AD0
AD1
AD2
AD3
WR
CS
A/D
IRQ
VOUT
VSS
V3025
PFO
VDD
VDD
VDD
VDD
VDD
VSS
VSS
VSS
VSS
Fig. 2
Fig. 1
Copyright © 2004, EM Microelectronic-Marin SA
1
www.emmicroelectronic.com