DS1556-70+ Maxim Integrated Products, DS1556-70+ Datasheet

IC RTC RAM Y2K 5V 70NS 32-EDIP

DS1556-70+

Manufacturer Part Number
DS1556-70+
Description
IC RTC RAM Y2K 5V 70NS 32-EDIP
Manufacturer
Maxim Integrated Products
Type
Clock/Calendar/NVSRAM/Y2Kr
Datasheet

Specifications of DS1556-70+

Memory Size
1M (128K x 8)
Time Format
HH:MM:SS (24 hr)
Date Format
YY-MM-DD-dd
Interface
Parallel
Voltage - Supply
4.5 V ~ 5.5 V
Operating Temperature
0°C ~ 70°C
Mounting Type
Through Hole
Package / Case
32-DIP Module (600 mil), 32-EDIP
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device
may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata.
FEATURES
 Integrated NV SRAM, Real-Time Clock
 Clock Registers are Accessed Identically to
 Century Byte Register (i.e., Y2K Compliant)
 Totally Nonvolatile with Over 10 Years of
 Precision Power-On Reset
 Programmable Watchdog Timer and RTC
 BCD-Coded Year, Month, Date, Day, Hours,
 Battery Voltage-Level Indicator Flag
 Power-Fail Write Protection Allows for 10%
 Lithium Energy Source is Electrically
 Also Available in Industrial Temperature
www.maxim-ic.com
19-5500; Rev 9/10
(RTC), Crystal, Power-Fail Control Circuit,
and Lithium Energy Source
the Static RAM; These Registers Reside in
the 16 Top RAM Locations
Operation in the Absence of Power
Alarm
Minutes, and seconds with Automatic Leap-
Year Compensation Valid Up to the Year
2100
V
Disconnected to Retain Freshness Until
Power is Applied for the First Time
Range: -40°C to +85°C
CC
Power-Supply Tolerance
1 of 18
1M, Nonvolatile, Y2K-Compliant
PIN CONFIGURATIONS
IRQ/FT
TOP VIEW
GND
DQ6
DQ7
DQ5
DQ4
DQ3
DQ2
DQ1
DQ0
RST
A15
A16
V
WE
OE
CE
CC
GND
DQ0
DQ1
DQ2
A16
A14
A12
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
RST
A7
A6
A5
A4
A3
A2
A1
A0
(Uses DS9034PCX PowerCap)
PowerCap Module Board
Encapsulated DIP
X1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Timekeeping RAM
GND
DS1556
DS1556
Maxim
Maxim
V
BAT
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
X2
V
A15
IRQ/FT
WE
A13
A8
A9
A11
OE
A10
CE
DQ7
DQ6
DQ5
DQ4
DQ3
CC
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
DS1556
N.C.
N.C.
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0

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DS1556-70+ Summary of contents

Page 1

... GND 16 Encapsulated DIP IRQ/FT 1 Maxim A15 2 DS1556 A16 3 RST DQ7 10 DQ6 11 DQ5 12 DQ4 13 DQ3 14 DQ2 15 DQ1 16 DQ0 X1 GND 17 GND PowerCap Module Board (Uses DS9034PCX PowerCap DS1556 A15 IRQ/ A13 A11 A10 DQ7 20 DQ6 19 DQ5 18 DQ4 17 DQ3 34 N.C. 33 N.C. 32 A14 31 A13 30 A12 29 ...

Page 2

... CC GND - Ground N. Connection X1 Crystal Connection V - Battery Connection BAT ORDERING INFORMATION PART TEMP RANGE DS1556-70+ 0°C to +70°C DS1556-70IND+ -40°C to +85°C DS1556P-70+ 0°C to +70°C DS1556P-70IND+ -40°C to +85°C DS1556W-120+ 0°C to +70°C DS1556W-120IND+ -40°C to +85°C DS1556WP-120+ 0°C to +70°C DS1556WP-120IND+ -40° ...

Page 3

... RTC alarm, watchdog timer, power-on reset, battery monitor, and 128k x 8 nonvolatile static RAM. User access to all registers within the DS1556 is accomplished with a byte-wide interface as shown in Figure 1. The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour BCD format ...

Page 4

... DATA WRITE MODE The DS1556 is in the write mode whenever WE and CE are in their active state. The start of a write is referenced to the latter occurring transition CE. The addresses must be held valid throughout the cycle. CE and WE must return inactive for a minimum write cycle ...

Page 5

... The DS1556 has a lithium power source that is designed to provide energy for the clock activity, and clock and RAM data retention when the V supply is sufficient to power the DS1556 continuously for the life of the equipment in which it is installed. For specification purposes, the life expectancy is 10 years at 25C with the internal clock oscillator running in the absence of V source disconnected, guaranteeing full energy capacity ...

Page 6

... The OSC bit is the MSB of the Seconds Register (B7 of 1FFF9h). Setting stops the oscillator, setting starts the oscillator. The DS1556 is shipped from Maxim with the clock oscillator turned off, OSC bit set DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM ...

Page 7

... CLOCK ACCURACY (DIP MODULE) The DS1556 is guaranteed to keep time accuracy to within 1 minute per month at 25C. The RTC is calibrated at the factory by Maxim using nonvolatile tuning elements, and does not require additional calibration. For this reason, methods of field clock calibration are not available and not necessary. The electrical environment also affects clock accuracy, and caution should be taken to place the RTC in the lowest-level EMI section of the PC board layout ...

Page 8

... The alarm can be programmed to activate on a specific day of the month or repeat every day, hour, minute, or second. It can also be programmed to go off while the DS1556 is in the battery-backed state of operation to serve as a system wake-up. Alarm mask bits AM1 to AM4 control the alarm mode. Table 3 shows the possible settings ...

Page 9

... AF. Therefore, the AF bit can be read after system power-up to determine if an alarm was generated during the power-up sequence. Figure 4 illustrates alarm timing during the battery-backup mode and power-up states. Figure 4. Backup Mode Alarm Waveforms DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM ...

Page 10

... Register is cleared. If the watchdog function is set to output to the IRQ/FT output and the frequency test function is activated, the watchdog function prevails and the frequency test function is denied. POWER-ON DEFAULT STATES Upon application of power to the device, the following register bits are set WDS = 0, BMB0 to BMB4 = 0, RB0 to RB1 = ABE = 0. DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM ...

Page 11

... Input Leakage Current (Any Input) Output Leakage Current (Any Output) Output Logic 1 Voltage (I = -1.0 mA) OUT Output Logic 0 Voltage Write Protection Voltage Battery Switchover Voltage DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM TEMP RANGE 0°C to +70°C -40°C to +85°C SYMBOL CONDITIONS = 5V 10 3.3V 10% ...

Page 12

... Input) Output Leakage Current (Any Output) Output Logic 1 Voltage (I = -1.0 mA) OUT Output Logic 0 Voltage Write Protection Voltage Battery Switchover Voltage Figure 5. Read Cycle Timing Diagram DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM SYMBOL CONDITIONS I (Notes (Notes 2, 3) CC1 I (Notes 2, 3) CC2 ...

Page 13

... Address Access Time WE Pulse Width CE Pulse Width Data Setup Time Data Hold Time (Note 9) Data Hold Time (Note 10) Address Hold Time (Note 9) Address Hold Time (Note 10) WE Data Off Time Write Recovery Time DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM = 5.0V 10 SYMBOL MIN MAX ...

Page 14

... Figure 6. Write Cycle Timing, Write-Enable Controlled Figure 7. Write Cycle Timing, Chip-Enable Controlled DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM ...

Page 15

... Power-Down V Fall Time PF(MAX) PF(MIN) V Fall Time PF(MIN Rise Time PF(MIN) PF(MAX) to RST High V PF Expected Data-Retention Time (Oscillator On) Figure 8. Power-Up/Down Waveform Timing (5V Device) DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM SYMBOL CONDITIONS REC (Notes MIN TYP MAX UNITS s 0 s 300 s 10  ...

Page 16

... V CC PF(MIN) PF(MAX) to RST High V PF Expected Data-Retention Time (Oscillator On) Figure 9. Power-Up/Down Waveform Timing (3.3V Device) CAPACITANCE (T = +25°C) A PARAMETER Capacitance on All Input Pins Capacitance on IRQ/FT, RST, and DQ Pins DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM SYMBOL CONDITIONS REC t (Notes SYMBOL CONDITIONS C (Note 1) IN ...

Page 17

... Battery switchover occurs at the lower of either the battery voltage The IRQ/FT and RST outputs are open drain. 6. Data-retention time is at +25C. 7. Each DS1556 has a built-in switch that disconnects the lithium source until V user. The expected t is defined for DIP modules and PowerCap modules as a cumulative time in the ...

Page 18

... 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  2010 Maxim Integrated Products DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM DESCRIPTION Maxim and the Dallas logo are registered trademarks of Maxim Integrated Products. ...

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