DS1556P Maxim Integrated Products, Inc., DS1556P Datasheet

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DS1556P

Manufacturer Part Number
DS1556P
Description
1m, Nonvolatile, Y2k-compliant Timekeeping Ram
Manufacturer
Maxim Integrated Products, Inc.
Datasheet

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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
PowerCap is a registered trademark of Dallas Semiconductor.
(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 21
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
Encapsulated DIP
X1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Semiconductor
Semiconductor
Timekeeping RAM
GND
DS1556
DS1556
Dallas
Dallas
®
Module Board
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
REV: 071305
N.C.
N.C.
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0

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DS1556P Summary of contents

Page 1

FEATURES § Integrated NV SRAM, Real-Time Clock (RTC), Crystal, Power-Fail Control Circuit, and Lithium Energy Source § Clock Registers are Accessed Identically to the Static RAM; These Registers Reside in the 16 Top RAM Locations § Century Byte Register ...

Page 2

... EMOD (0.740a) 5.0 32 EMOD (0.740a) 5.0 32 EMOD (0.740a) 5.0 32 EMOD (0.740a) 5.0 34 PowerCap* 5.0 34 PowerCap* 5.0 34 PowerCap* 5.0 34 PowerCap* 3.3 32 EMOD (0.740a) 3.3 32 EMOD (0.740a) 3.3 32 EMOD (0.740a) 3.3 34 PowerCap* 3.3 34 PowerCap* 3.3 34 PowerCap* 3.3 34 PowerCap TOP MARK** DS1556-070 DS1556070 DS1556-070 DS1556070 DS1556P-70 DS1556P+70 DS1556P-70 DS1556P+70 DS1556W-120 DS1556W-120 DS1556W120 DS1556WP-120 DS1556WP+120 DS1556WP-120 DS1556WP+120 ...

Page 3

... This design allows the PowerCap to be mounted on top of the DS1556P after the completion of the surface mount process. Mounting the PowerCap after the surface mount process prevents damage to the crystal and battery due to the high temperatures required for solder reflow ...

Page 4

Figure 1. Block Diagram Table 1. Operating Modes > < V < ...

Page 5

OE signal will be high during a write cycle. However, OE can be active provided that care is taken with the data bus to avoid bus contention low prior to WE transitioning low, ...

Page 6

CLOCK OPERATIONS Table 2 and the following paragraphs describe the operation of RTC, alarm, and watchdog functions. Table 2. Register Map ADDRESS 1FFFFh 10 Year 1FFFEh X X 1FFFDh X X 1FFFCh X Ft 1FFFBh X ...

Page 7

READING THE CLOCK When reading the RTC data recommended to halt updates to the external set of double-buffered RTC Registers. This puts the external registers into a static state allowing data to be read without register values changing ...

Page 8

USING THE CLOCK ALARM The alarm settings and control for the DS1556 reside within Registers 1FFF2h to 1FFF5h. Register 1FFF6h contains two alarm enable bits: Alarm Enable (AE) and Alarm in Backup Enable (ABE). The AE and ABE bits must ...

Page 9

Figure 3. Clearing IRQ Waveforms CE=0 The IRQ/FT pin can also be activated in the battery-backed mode. The IRQ/FT will go low if an alarm occurs and both ABE and AE are set. The ABE and AE bits are cleared ...

Page 10

USING THE WATCHDOG TIMER The watchdog timer can be used to detect an out-of-control processor. The user programs the watchdog timer by setting the desired amount of time-out into the 8-bit Watchdog Register (Address 1FFF7h). The five Watchdog Register bits ...

Page 11

ABSOLUTE MAXIMUM RATINGS Voltage Range on Any Pin Relative to Ground……………………..………………………-0.3V to +6.0V Storage Temperature Range………………………………………………………………...-40°C to +85°C Soldering Temperature…………………………………...See IPC/JEDEC Standard J-STD-020A (Note 8) This is a stress rating only and functional operation of the device at these or ...

Page 12

DC ELECTRICAL CHARACTERISTICS (V = 3.3V ±10%, Over the Operating Range.) CC PARAMETER Active Supply Current TTL Standby Current ( CMOS Standby Current (CE ³ 0.2V) CC Input Leakage Current (Any Input) Output Leakage ...

Page 13

AC CHARACTERISTICS—READ CYCLE (Over the Operating Range) PARAMETER Read Cycle Time Address Access Time Low-Z CE Access Time CE Data Off Time Low-Z OE Access Time OE Data Off Time Output Hold from Address ...

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-UP/DOWN CHARACTERISTICS— 5.0V ±10%, Over the Operating Range.) CC PARAMETER Before IH Power-Down V Fall Time PF(MAX) PF(MIN) V Fall Time PF(MIN ...

Page 16

POWER-UP/DOWN CHARACTERISTICS—3. 3.3V ±10%, Over the Operating Range.) CC PARAMETER Before IH Power-Down V Fall Time PF(MAX) PF(MIN) V Rise Time PF(MIN) PF(MAX) V ...

Page 17

AC TEST CONDITIONS Output Load 1TTL Gate Input Pulse Levels: 0.0 to 3.0V Timing Measurement Reference Levels: Input: 1.5V Output: 1.5V Input Pulse Rise and Fall Times NOTES: 1. Voltage referenced to ground. 2. Typical ...

Page 18

PACKAGE INFORMATION (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/DallasPackInfo.) DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM PKG 32-PIN DIM MIN A IN. 1.670 MM 38.42 ...

Page 19

... PACKAGE INFORMATION (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/DallasPackInfo.) DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM DS1556P PKG DIM MIN A 0.920 B 0.980 C — D 0.052 E 0.048 F 0.015 G 0.025 ...

Page 20

... PACKAGE INFORMATION (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/DallasPackInfo.) DS1556P WITH DS9034PCX ATTACHED DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM ...

Page 21

... The Maxim logo is a registered trademark of Maxim Integrated Products, Inc. The Dallas logo is a registered trademark of Dallas Semiconductor Corporation. ...

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