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DS1388_08 Datasheet

Download or read online Maxim Integrated DS1388_08 I2C RTC/Supervisor with Trickle Charger and 512 Bytes EEPROM pdf datasheet.



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Rev 1; 9/08
2
I
C RTC/Supervisor with Trickle Charger
General Description
2
The DS1388 I
C real-time clock (RTC), supervisor, and
EEPROM is a multifunction device that provides a
clock/calendar, programmable watchdog timer, power-
supply monitor with reset, and 512 bytes of EEPROM.
The clock provides hundredths of seconds, seconds,
minutes, and hours, and operates in 24-hour or 12-hour
format with an AM/PM indicator. The calendar provides
day, date, month, and year information. The date at the
end of the month is automatically adjusted for months
with fewer than 31 days, including corrections for leap
year. A watchdog timer provides a reset for an unre-
sponsive microprocessor. It is programmable in 10ms
intervals from 0.01 to 99.99 seconds. A temperature-
compensated voltage reference and comparator circuit
monitors the status of V
. If a primary power failure is
CC
detected, the device automatically switches to the
backup supply and drives the reset output to the active
state. The backup supply maintains time and date
operation in the absence of V
. When V
CC
nominal levels, the reset is held low for a period to allow
the power supply and processor to stabilize. The
device also has a pushbutton reset controller, which
debounces a reset input signal. The device is
2
accessed through an I
C serial interface.
Portable Instruments
Point-of-Sale Equipment
Network Interface Cards
Wireless Equipment
Pin Configuration
TOP VIEW
+
X1
1
X2
2
DS1388
V
3
BACKUP
GND
4
SO
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
and 512 Bytes EEPROM
♦ Fast (400kHz) I
♦ RTC Counts Hundredths of Seconds, Seconds,
Minutes, Hours, Day, Date, Month, and Year with
Leap Year Compensation Valid Up to 2100
♦ Programmable Watchdog Timer
♦ Automatic Power-Fail Detect and Switch Circuitry
♦ Reset Output with Pushbutton Reset Input
Capability
♦ 512 x 8 Bits of EEPROM
♦ Integrated Trickle-Charge Capability for Backup
Supply
♦ Three Operating Voltages: 5.0V, 3.3V, and 3.0V
♦ Low Timekeeping Voltage Down to 1.3V
♦ -40°C to +85°C Temperature Range
♦ UL Recognized
returns to
CC
PART
DS1388Z-5+
Applications
DS1388Z-33+
DS1388Z-3+
+ Denotes a lead-free/RoHS-compliant package.
V
CC
V
8
CC
7
RST
6
SCL
CPU
5
SDA
RPU = t
______________________________________________ Maxim Integrated Products
Features
2
C Interface
Ordering Information
TEMP RANGE PIN-PACKAGE
-40°C to +85°C 8 SO (150 mils) DS1388-5
-40°C to +85°C 8 SO (150 mils) DS138833
-40°C to +85°C 8 SO (150 mils) DS1388-3
Typical Operating Circuit
CRYSTAL
V
V
CC
CC
X2
X1
V
CC
RPU
RPU
SCL
DS1388
SDA
RST
V
BACKUP
GND
/C
R
B
TOP
MARK
1

Summary of Contents

Page 1

... CC 7 RST 6 SCL CPU 5 SDA RPU t ___ Maxim Integrated Products Features 2 C Interface Ordering Information TEMP RANGE PIN-PACKAGE -40°C to 85° (150 mils) DS1388-5 -40°C to 85° (150 mils) DS138833 -40°C to 85° (150 mils) DS1388-3 Typical Operating Circuit ...

Page 2

I C RTC/Supervisor with Trickle Charger and 512 Bytes EEPROM ABSOLUTE MAXIMUM RATINGS Voltage Range on V Pin Relative to Ground ...-0.3V to 6.0V CC Voltage Range on Inputs Relative to Ground ...-0. Operating Temperature Range (noncondensing) ...

Page 3

I C RTC/Supervisor with Trickle Charger DC ELECTRICAL CHARACTERISTICS (continued -40°C to 85°C, unless otherwise noted.) (Note 1) CC CC(MIN) CC(MAX) A PARAMETER SYMBOL RST Logic 0 Output V Active Current, ...

Page 4

I C RTC/Supervisor with Trickle Charger and 512 Bytes EEPROM AC ELECTRICAL CHARACTERISTICS ( -40°C to 85°C, unless otherwise noted.) (Note 1) CC CC(MIN) CC(MAX) A PARAMETER SYMBOL SCL Clock Frequency Bus ...

Page 5

I C RTC/Supervisor with Trickle Charger POWER-UP/POWER-DOWN CHARACTERISTICS (T -40°C to 85°C) (Note 1) (Figures PARAMETER V Detect to Recognize Inputs CC (V Rising Fall Time PF(MAX) PF(MIN) V ...

Page 6

I C RTC/Supervisor with Trickle Charger and 512 Bytes EEPROM WARNING: Under no circumstances are negative undershoots, of any amplitude, allowed when device is in write protection. Note 1: Limits at -40°C are guaranteed by design and are not ...

Page 7

I C RTC/Supervisor with Trickle Charger (V 3.3V 25°C, unless otherwise noted SUPPLY CURRENT VOLTAGE BACKUP vs. V BACKUP 500 450 400 350 300 250 1.3 1.7 2.1 2.5 ...

Page 8

I C RTC/Supervisor with Trickle Charger and 512 Bytes EEPROM PIN NAME Connections for a Standard 32.768kHz Quartz Crystal. The internal oscillator circuitry is designed for 1 X1 operation with a crystal having a specified load capacitance (C oscillator ...

Page 9

I C RTC/Supervisor with Trickle Charger Detailed Description 2 The DS1388 I C RTC, supervisor, and EEPROM is a multifunction device that provides a clock/calendar, programmable watchdog timer, power-supply monitor with reset, and 512 bytes of EEPROM. The clock ...

Page 10

I C RTC/Supervisor with Trickle Charger and 512 Bytes EEPROM LOCAL GROUND PLANE (LAYER 2) NOTE: AVOID ROUTING SIGNAL LINES IN THE CROSSHATCHED AREA (UPPER LEFT QUADRANT) OF THE PACKAGE UNLESS THERE IS A GROUND PLANE BETWEEN THE SIGNAL ...

Page 11

I C RTC/Supervisor with Trickle Charger ADDRESS BIT 7 BIT 6 BLK WORD 0H 00H Tenth Seconds 0H 01H 0 10 Seconds 0H 02H 0 10 Minutes 0H 03H 0 12/24 0H 04H 05H 0 0 ...

Page 12

I C RTC/Supervisor with Trickle Charger and 512 Bytes EEPROM Watchdog Alarm Counter The contents of the watchdog alarm counter, which is a separate two-byte BCD down counter, are accessed in the address range 08h09h in block 0h. It ...

Page 13

I C RTC/Supervisor with Trickle Charger BIT 7 BIT 6 BIT 5 EOSC 0 Control Register (00Ch) Bit 7: Enable Oscillator (EOSC). When set to logic 0, the oscillator is started. When set to logic 1, the oscillator is ...

Page 14

I C RTC/Supervisor with Trickle Charger and 512 Bytes EEPROM TRICKLE-CHARGE REGISTER (00Ah) BIT 6 BIT 5 BIT 4 BIT 7 TCS3 TCS2 TCS1 TCS0 SELECT NOTE: ONLY 1010b ENABLES CHARGER V CC Figure 5. Programmable ...

Page 15

I C RTC/Supervisor with Trickle Charger Each data transfer is initiated with a START condition and terminated with a STOP condition. The number of data bytes transferred between the START and the STOP conditions is not limited, and is ...

Page 16

I C RTC/Supervisor with Trickle Charger and 512 Bytes EEPROM Device Addressing The slave address byte is the first byte received follow- ing the START condition from the master device. The slave address byte consists of a 4-bit control ...

Page 17

I C RTC/Supervisor with Trickle Charger Acknowledge Polling Since the DS1388 does not acknowledge during an EEPROM write cycle, acknowledge polling can be used to determine when the cycle is complete (this feature can be used to maximize bus ...

Page 18

I C RTC/Supervisor with Trickle Charger and 512 Bytes EEPROM S 1101BBB 1 A XXXXXXXX B - BLOCK SELECT MASTER TO SLAVE S - START A - ACKNOWLEDGE (ACK STOP A - ...

Page 19

... Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ___ 19 © 2008 Maxim Integrated Products is a registered trademark of Dallas Semiconductor Corporation ...

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