DS12R885-5 MAXIM [Maxim Integrated Products], DS12R885-5 Datasheet

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DS12R885-5

Manufacturer Part Number
DS12R885-5
Description
RTC with Constant-Voltage Trickle Charger
Manufacturer
MAXIM [Maxim Integrated Products]
Datasheet
The DS12R885 is a functional drop-in replacement for
the DS12885 real-time clock (RTC). The device pro-
vides an RTC/calendar, one time-of-day alarm, three
maskable interrupts with a common interrupt output, a
programmable square wave, and 114 bytes of battery-
backed static RAM. The date at the end of the month is
automatically adjusted for months with fewer than 31
days, including correction for leap years. It also oper-
ates in either 24-hour or 12-hour format with an AM/PM
indicator. A precision temperature-compensated circuit
monitors the status of V
detected, the device automatically switches to a back-
up supply. The V
battery or a super cap and includes an integrated,
always enabled trickle charger. The DS12R885 is
accessed through a multiplexed byte-wide interface,
which supports both Intel and Motorola modes. The
DS12CR887 and DS12R887 integrate the DS12R885
die with a crystal and battery.
Rev 1; 4/04
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Embedded Systems
Utility Meters
Security Systems
Network Hubs, Bridges, and Routers
DS83C520
RTC with Constant-Voltage Trickle Charger
Typical Operating Circuit
BACKUP
General Description
CC
AS
R/W
DS
CS
AD(0–7)
IRQ
MOT
X1
CRYSTAL
pin supports a rechargeable
. If a primary power failure is
DS12R885
X2
GND
Applications
V
BACKUP
V
V
RESET
______________________________________________ Maxim Integrated Products
RCLR
CC
CC
SQW
±
SUPER
CAP
♦ Trickle-Charge Capability for a Rechargeable
♦ Selectable Intel or Motorola Bus Timing
♦ RTC Counts Seconds, Minutes, Hours, Day, Date,
♦ Interrupt Output with Three Independently
♦ Time-of-Day Alarm is Once-per-Second to Once-
♦ Periodic Rates from 122µs to 500ms
♦ End-of-Clock Update Cycle Flag
♦ 14 Bytes of Clock and Control Registers
♦ 114 Bytes of General-Purpose RAM with Clear Input
♦ Programmable Square-Wave Output
♦ Automatic Power-Fail Detect and Switch Circuitry
♦ +5.0V or +3.3V Operation
♦ Industrial Temperature Range
♦ DS12CR887 Encapsulated DIP (EDIP) Module with
♦ DS12R887 BGA Module Surface-Mountable
*Future product—contact factory for availability.
Pin Configurations appear at end of data sheet.
DS12R885-5
DS12R885-33
DS12CR887-5
D S 12C R887- 33
DS12R887-5*
DS12R887-33*
Battery or Super Cap
Month, and Year with Leap-Year Compensation to
2100
Maskable Interrupt Flags
per-Day
Integrated Battery and Crystal
Package with Integrated Crystal and Rechargeable
Battery
PART
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C 48 BGA
-40°C to +85°C 48 BGA
TEMP RANGE
Ordering Information
PIN-
PA CKA GE
24 SO
(300 mils)
24 SO
(300 mils)
24 EDIP
(700 mils)
24 EDIP
(700 mils)
Features
DS12R885-5
DS12R885-33
DS12CR887-5
DS12CR887-33
DS12R887-5
DS12R887-33
TOP MARK
1

Related parts for DS12R885-5

DS12R885-5 Summary of contents

Page 1

... Pin Configurations appear at end of data sheet. ______________________________________________ Maxim Integrated Products Features Ordering Information PIN- TEMP RANGE TOP MARK PA CKA -40°C to +85°C DS12R885-5 (300 mils -40°C to +85°C DS12R885-33 (300 mils) 24 EDIP -40°C to +85°C DS12CR887-5 (700 mils) ...

Page 2

... V (Note (Note 2) IL -33 CC1 -5 -5 CCS - (Note 5) OL (Note 6) MOT I (Note (Note -33 TRIP -5 R1 DS12R885 Only DS12R885 Only OUT J-STD-020A Specification MIN TYP MAX UNITS 2.97 3.3 3.63 V 4.5 5.0 5.5 2 OUT 2.2 V 0.3 -0.3 +0 0.8 2 0.250 0.5 mA 0.140 ...

Page 3

... RTC with Constant-Voltage Trickle Charger DC ELECTRICAL CHARACTERISTICS (DS12R885 Only 0V 3.2V -40°C to +85°C, unless otherwise noted.) (Note 1) CC BACKUP A PARAMETER SYMBOL V Current (OSC On); BACKUP I BACKUP2 T = +25° 3.0V A BACKUP V Current (Oscillator Off) I BACKUP BACKUPDR AC ELECTRICAL CHARACTERISTICS (V = 4.5V to 5.5V -40°C to +85°C.) (Note 1) ...

Page 4

RTC with Constant-Voltage Trickle Charger AC ELECTRICAL CHARACTERISTICS (V = 2.97V to 3.63V -40°C to +85°C.) (Note PARAMETER SYMBOL Cycle Time Pulse Width, DS Low or R/W High PW Pulse Width, DS High or R/W ...

Page 5

RTC with Constant-Voltage Trickle Charger ASD AD0–AD7 WRITE AD0–AD7 READ AS PW ASH t ASD DS t ASD R ASL AD0–AD7 WRITE _____________________________________________________________________ Motorola Bus Read/Write Timing ASH t ASED ...

Page 6

RTC with Constant-Voltage Trickle Charger AS t ASD DS t ASD R/W CS AD0–AD7 IRQ Release Delay Timing DS RESET IRQ t IRDS PF(MAX) V PF(MIN) RECOGNIZED INPUTS VALID OUTPUTS 6 _____________________________________________________________________ t CYC PW ASH t ...

Page 7

RTC with Constant-Voltage Trickle Charger POWER-UP/POWER-DOWN CHARACTERISTICS (T = -40°C to +85°C) (Note 1) A PARAMETER SYMBOL Recovery at Power-Up V Fall Time PF(MAX) V PF(MIN) V Rise Time PF(MIN) V PF(MAX) CAPACITANCE (T ...

Page 8

... TEMPERATURE (°C) 8 _____________________________________________________________________ Typical Operating Characteristics BACKUP 2.5 2.8 3.0 (V) 32768.10 32768.08 32768.06 32768.04 32768.02 32768.00 32767.98 32767.96 32767.94 32767.92 32767. vs. V vs. I BACKUP CC BACKUP (DS12R885) DS12R885 toc02 3.0 0µA -15µA 2.8 -30µA 2.6 -45µA 2.4 -60µA 2.2 2.0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5 OSCILLATOR FREQUENCY vs. SUPPLY VOLTAGE 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY (V) ...

Page 9

... DS12R885 by the falling edge of AS. Write data is latched by the falling edge of DS (Motorola timing) or the rising edge of R/W (Intel timing read cycle, the DS12R885 outputs data during the latter portion of DS (DS and R/W high for Motorola timing, DS low and R/W high for Intel timing). The read cycle is terminated and the bus returns to a high-impedance state as DS transitions low in the case of Motorola timing transitions high in the case of Intel timing ...

Page 10

... Ground Chip-Select Input. The active-low chip-select signal must be asserted low for a bus cycle in the DS12R885 to be accessed. CS must be kept in the active state during DS and AS for Motorola timing and during DS and R/W for Intel timing. Bus cycles that take place without asserting CS latch addresses, but no access occurs. When V the DS12R885 inhibits access by internally disabling the CS input ...

Page 11

... In a typical application, RESET can be connected to V DS12R885 and out of power fail without affecting any of the control registers. Interrupt Request Output. The IRQ pin is an active-low output of the DS12R885 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 ...

Page 12

... A circuit using a crystal with the recommended characteristics and proper layout usually starts within one second. An external 32.768kHz oscillator can also drive the DS12R885. In this configuration, the X1 pin is connected to the external oscillator signal and the X2 pin is floated. Table 1. Crystal Specifications* ...

Page 13

RTC with Constant-Voltage Trickle Charger Clock Accuracy The accuracy of the clock is dependent upon the accu- racy of the crystal and the accuracy of the match between the capacitive load of the oscillator circuit and the capacitive load for ...

Page 14

RTC with Constant-Voltage Trickle Charger The three alarm bytes can be used in two ways. First, when the alarm time is written in the appropriate hours, minutes, and seconds alarm locations, the alarm inter- rupt is initiated at the specified ...

Page 15

RTC with Constant-Voltage Trickle Charger Table 2B. Time, Calendar, and Alarm Data Modes—Binary Mode ( ADDRESS BIT 7 BIT 6 BIT 5 00H 0 0 01H 0 0 02H 0 0 03H 0 0 AM/PM 04H 0 0 ...

Page 16

... RTC with Constant-Voltage Trickle Charger Control Registers The DS12R885 has four control registers that are accessible at all times, even during the update cycle. BIT 7 BIT 6 BIT 5 UIP DV2 DV1 Bit 7: Update-In-Progress (UIP). This bit is a status flag that can be monitored. When the UIP bit the update transfer occurs soon. When UIP the update transfer does not occur for at least 244µ ...

Page 17

... The AF bit does not initiate the IRQ signal when the AIE bit is set to 0. The internal functions of the DS12R885 do not affect the AIE bit, but is cleared RESET. Bit 4: Update-Ended Interrupt Enable (UIE). This bit is a read/write bit that enables the update-end flag (UF) bit in Register C to assert IRQ ...

Page 18

RTC with Constant-Voltage Trickle Charger BIT 7 BIT 6 BIT 5 IRQF PF Bit 7: Interrupt Request Flag (IRQF). This bit is set to 1 when any of the following are true PIE = AIE ...

Page 19

... RTC with Constant-Voltage Trickle Charger Nonvolatile RAM (NV RAM) The 114 general-purpose NV RAM bytes are not dedi- cated to any special function within the DS12R885. They can be used by the processor program as battery-backed memory and are fully available during the update cycle. The DS12R885 includes three separate, fully automatic sources of interrupt for a processor ...

Page 20

... Update Cycle The DS12R885 executes an update cycle once per second regardless of the SET bit in Register B. When the SET bit in Register B is set to 1, the user copy of the double-buffered time, calendar, and alarm bytes is frozen and does not update as the time increments. ...

Page 21

... The BGA package can be reflowed as long as the fol- lowing conditions are met: 1. Preheating (below 160°C) is within 90 seconds. 2. Maximum time above 150°C is less than 180 seconds. TOP VIEW MOT AD0 4 AD1 5 DS12R885 AD2 6 AD3 7 AD4 8 AD5 9 AD6 10 AD7 11 GND 12 SO (0.300" ...

Page 22

RTC with Constant-Voltage Trickle Charger Pin Configurations (continued) TOP VIEW (BUMP SIDE DOWN DS12R887 RESET IRQ V SQW CC 4 RCLR V MOT ...

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