Low Power RTC with Battery Backed SRAM,
Integrated ±5ppm Temperature Compensation and
Auto Daylight Saving
ISL12022MR5421
Features
• Embedded 32.768kHz Quartz Crystal in the Package
The ISL12022MR5421 device is a low power real time
clock (RTC) with an embedded temperature sensor and
crystal. Device functions include oscillator compensation,
clock/calendar, power fail and low battery monitors,
brownout indicator, one-time, periodic or polled alarms,
intelligent battery backup switching, Battery Reseal™
function and 128 bytes of battery-backed user SRAM.
The device is offered in a 20 Ld SOIC module that
contains the RTC and an embedded 32.768kHz quartz
crystal. The calibrated oscillator provides less than
±5ppm drift over the full -40°C to +85°C temperature
range.
• 20 Ld SOIC Package (for DFN version, refer to the
ISL12020M)
• Calendar
• On-chip Oscillator Temperature Compensation
• 10-bit Digital Temperature Sensor Output
• 15 Selectable Frequency Outputs
• Interrupt for Alarm or 15 Selectable Frequency
Outputs
• Automatic Backup to Battery or Supercapacitor
• VDD and Battery Status Monitors
The RTC tracks time with separate registers for hours,
minutes, and seconds. The calendar registers track date,
month, year and day of the week and are accurate
through 2099, with automatic leap year correction.
• Battery Reseal™ Function to Extend Battery Shelf
Life
• Power Status Brownout Monitor
• Time Stamp for Battery Switchover
• 128 Bytes Battery-Backed User SRAM
Daylight Savings time adjustment is done automatically,
using parameters entered by the user. Power fail and
battery monitors offer user-selectable trip levels. The
time stamp function records the time and date of
2
• I C-Bus™
• RoHS Compliant
switchover from V
to V
power, and also from V
DD
BAT
BAT
to V
DD
power.
Applications
The ISL12022MR5421 has redesign package to increase
Contact and Air Discharge ESD performance.
• Utility Meters
• POS Equipment
• Printers and Copiers
• Digital Cameras
Related Literature
• See AN1549 “Addressing Power Issues in Real Time
Clock Applications”
Typical Application Circuit
Performance Curve
OSCILLATOR ERROR vs TEMPERATURE
5
1
2
3
4
5
20
19
18
17
16
4
3
2
1
GND
GND
GND
GND
GND
NC
GND
NC
3.3V
NC
NC
C1
0.1µF
SCHOTTKY DIODE
BAT54
V
= 5.5V
BAT
6
7
15
14
R1 R2 R3
10k 10k 10k
0
-1
-2
-3
-4
-5
GND
GND
V
V
DD
BAT
V
= 2.7V
8
9
13
12
11
BATTERY
3.0V
C2
0.1µF
DD
60
VDO
SCL
GND IRQ/F
OUT
MCU
INTERFACE
NC
SCL
10
NC
SDA
V
= 3.3V
SDA
GND
DD
ISL12022MR5421
IRQ/F
OUT
-40
-20
0
20
40
80
TEMPERATURE (°C)
June 4, 2010
FN7576.1
These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
2
I C Bus is a registered trademark owned by NXP Semiconductors Netherlands, B.V.
Copyright Intersil Americas Inc. 2010. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.