Rainbow Electronics DS1500 User Manual
www.maxim-ic.com
GENERAL DESCRIPTION
The DS1500 is a full-function, year 2000-compliant
real-time clock/calendar (RTC) with an alarm,
watchdog timer, power-on reset, battery monitors,
256 bytes of on-board nonvolatile (NV) SRAM, NV
control for backing up an external SRAM, and a
32.768kHz output. User access to all registers within
the DS1500 is accomplished with a byte-wide
interface, as shown in Figure 7. The RTC registers
contain century, year, month, date, day, hours,
minutes, and seconds data in 24-hour binary-coded
decimal (BCD) format. Corrections for day of month
and leap year are made automatically.
APPLICATIONS
Remote Systems
Battery-Backed Systems
Telecom Switches
Office Equipment
Consumer Electronics
ORDERING INFORMATION
PART TEMP RANGE PIN-PACKAGE
DS1500YEN
DS1500WEN -40°C to +85°C 32 TSOP
Selector Guide appears at end of data sheet.
Typical Operating Circuit appears at end of data sheet.
-40°C to +85°C 32 TSOP
DS1500
Y2K Watchdog RTC with
Nonvolatile Control
FEATURES
§ BCD-Coded Century, Year, Month, Date, Day,
Hours, Minutes, and Seconds with Automatic
Leap-Year Compensation Valid Up to the Year
2100
§ Programmable Watchdog Timer and RTC Alarm
§ Century Register; Y2K-Compliant RTC
§ Automatic Battery Backup and Write Protection
to External SRAM
§ +5V Operation
§ Precision Power-On Reset
§ Power-Control Circuitry Supports System Power-
On from Date/Day/Time Alarm or Key Closure
§ 256 Bytes User NV RAM
§ Auxiliary Battery Input
§ Accuracy Better than ±1 Minute/Month at +25°C
§ Day-of-Week/Date Alarm Register
§ Battery Voltage-Level Indicator Flags
§ Industrial Temperature Range: -40°C to +85°C
PIN CONFIGURATION
TOP VIEW
Dallas
Semiconductor
DS1500
TSOP
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
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REV: 030603
.
DS1500 Y2KC Watchdog RTC with Nonvolatile Control
ABSOLUTE MAXIMUM RATINGS
Voltage Range on Any Pin Relative to Ground -0.5V to +6.0V
Operating Temperature Range
Storage Temperature Range
Soldering Temperature
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only,
and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is
not implied. Exposure to the absolute maximum rating conditions for extended periods may affect device.
See IPC/JEDEC J-STD-020A Specification
-40°C to +85°C (Note 1)
-55°C to +125°C
RECOMMENDED DC OPERATING CONDITIONS
(TA = -40°C to +85°C)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Power Supply Voltage (Note 2)
Logic 1 Voltage All Inputs (Note 2)
Pullup Voltage, IRQ, PWR, and RST Outputs
Logic 0 Voltage All Inputs (Note 2)
Battery Voltage (Note 2)
Auxiliary Battery Voltage (Note 2)
VCC
V
VPU
VIL
V
V
BAUX
IH
BAT
5V (Y) 4.5 5.0 5.5
3.3V (W) 3.0 3.3 3.6
+
V
V
CC
0.3
CC
0.3
+
Y 2.2
W 2.0
(Note 2) 5.5 V
Y -0.3 +0.8
W -0.3 +0.6
2.5 3.0 3.7 V
Y 2.5 3.0 5.3
W 2.5 3.0 3.7
V
V
V
V
DC ELECTRICAL CHARACTERISTICS
(V
< V
CCMIN
CCI
< V
, TA = -40°C to +85°C.)
CCMAX
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Active Supply Current (Note 3) ICC
TTL Standby Current (CS = VIH) I
CMOS Standby Current
(CS ³ V
- 0.2V)
CCI
I
CC1
CC2
Y 15
W 10
Y 5
W 4
Y 5
W 4
Input Leakage Current (Any Input) IIL -1 +1
Output Leakage Current (Any Output) IOL -1 +1
Output Logic 1 Voltage (I
Output Logic 0 Voltage (I
DQ0–7,
I
OUT
CEO I
= 5.0mA, IRQ,
OUT
= 7.0mA PWR, and RST)
Battery Low, Flag Trip Point (Note 2) V
Output Voltage (I
= 85mA ) (Note 5) V
CCO1
Power-Fail Voltage (Note 2) VPF
Battery Switchover Voltage VSO (Notes 2, 6)
Output Voltage (I
= 50µA) V
CCO2
Battery Leakage Current I
= -1.0mA) VOH (Note 2) 2.4 V
OUT
= 2.1mA,
OUT
V
(Note 2) 0.4 V
OL1
(Notes 2, 4) 0.4 V
V
OL2
Y 2.0
BLF
CCO1
W 1.9
Y
W
V
CCI
0.3
-
Y 4.20 4.50
W 2.75 2.97
V
BAT,
V
BAUX,
or V
PF
-
V
(Note 7)
CCO2
10 100 nA
LKG
BAT
0.3
V
V
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mA
mA
mA
mA
mA
V
V
V
DS1500 Y2KC Watchdog RTC with Nonvolatile Control
DC ELECTRICAL CHARACTERISTICS
(VCC = 0V, TA = -40°C to +85°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Battery Current, BB32 = 0, EOSC = 0
Battery Current, BB32 = 0, EOSC = 1
V
Current BB32 = 1, SQW Open I
BAUX
BAT1
I
BAT2
BAUX
(Notes 8, 9)
(Notes 8, 9)
(Notes 8, 9) 2 µA
0.27 1.0 µA
0.01 0.1 µA
I
CRYSTAL SPECIFICATIONS*
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Nominal Frequency fO 32.768 kHz
Series Resistance ESR 45 kΩ
Load Capacitance CL 6 pF
*The crystal, traces, and crystal input pins should be isolated from RF generating signals. Refer to Application Note 58: Crystal Considerations
for Dallas Real-Time Clocks for additional specifications.
AC OPERATING CHARACTERISTICS
(V
= 5.0V ±10%, TA = -40°C to +85°C.)
CCI
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Read Cycle Time tRC
Address Access Time tAA
CS to DQ Low-Z
CS Access Time
CS Data Off Time
OE to DQ Low-Z (0°C to +85°C)
OE to DQ Low-Z (-40°C to 0°C)
OE Access Time
OE Data Off Time
Output Hold from Address tOH
Write Cycle Time
Address Setup Time
WE Pulse Width
CS Pulse Width
Data Setup Time
Data Hold Time
Address Hold Time
WE Data Off Time
Write Recovery Time
CEI to CEO Propagation Delay
Pulse Width, OE, WE, or CS High
Pulse Width, OE, WE, or CS Low
PW
PW
t
(Note 10)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
t
t
t
t
t
t
CSL
CSA
CSZ
OEL
OEL
OEA
OEZ
70 ns
t
WC
0 ns
t
AS
t
50 ns
WEW
t
55 ns
CSW
30 ns
t
DS
t
5 ns
DH
0 ns
t
AH
t
(Note 10) 25 ns
WEZ
t
15 ns
WR
10 ns
t
CEPD
20 ns
HIGH
70 ns
LOW
70 ns
70 ns
5 ns
70 ns
25 ns
5 ns
2 ns
35 ns
25 ns
5 ns
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DS1500 Y2KC Watchdog RTC with Nonvolatile Control
AC OPERATING CHARACTERISTICS (continued)
(V
= 3.3V ±10%, TA = -40°C to +85°C.)
CCI
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Read Cycle Time
Address Access Time
CS to DQ Low-Z
CS Access Time
CS Data Off Time
OE to DQ Low-Z (0°C to +85°C)
OE to DQ Low-Z (-40°C to 0°C)
OE Access Time
OE Data Off Time
Output Hold from Address
Write Cycle Time
Address Setup Time
WE Pulse Width
CS Pulse Width
Data Setup Time
Data Hold Time
Address Hold Time
WE Data Off Time
Write Recovery Time
CEI to CEO Propagation Delay
Pulse Width, OE, WE, or CS High
Pulse Width, OE, WE, or CS Low
Figure 1. Read Cycle Timing
120 ns
t
RC
120 ns
t
AA
(Note 10) 5 ns
t
CSL
t
120 ns
CSA
t
(Note 10) 40 ns
CSZ
(Note 10) 5 ns
t
OEL
t
(Note 10) 2 ns
OEL
t
100 ns
OEA
t
(Note 10) 35 ns
OEZ
5 ns
t
OH
120 ns
t
WC
0 ns
t
AS
t
100 ns
WEW
t
110 ns
CSW
80 ns
t
DS
5 ns
t
DH
0 ns
t
AH
t
(Note 10) 40 ns
WEZ
15 ns
t
WR
t
10 ns
CEPD
PW
PW
40 ns
HIGH
100 ns
LOW
t
RC
A0-A4
t
CS
OE
DQ0-DQ7
t
AA
t
CSA
t
CSL
t
OEA
t
OEL
VALID
t
OEZ
OH
t
CSZ
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DS1500 Y2KC Watchdog RTC with Nonvolatile Control
Figure 2. Write Cycle Timing, Write-Enable-Controlled
t
WC
A0-A4
VALID VALID
DATA INPUT
t
AH
t
DH
t
CS
WE
DQ0-DQ7
AS
t
AS
DATA OUTPUT DATA INPUT
t
WEW
t
WEZ
t
D
S
Figure 3. Write Cycle Timing, Chip-Select-Controlled
t
WR
A0-A4
CS
WE
DQ0-DQ7
t
WC
VALID VALID
t
AS
t
AS
t
CSW
t
DS
DATA INPU T
t
AH
t
WR
t
DH
DATA INPUT
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Figure 4. Burst Mode Timing Waveform
O
DS1500 Y2KC Watchdog RTC with Nonvolatile Control
A0–A4
E, WE, OR CS
DQ0–DQ7
13h
LOW
PW
HIGH
PW
POWER-UP/DOWN CHARACTERISTICS (Figure 5)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
CS, CEI, or WE at V
V
Fall Time: V
CCI
V
Fall Time: V
CCI
V
Rise Time: V
CCI
PF(MAX)
PF(MIN)
PF(MIN)
VPF to RST High
t
t
REC
PF
FB
F
R
Before Power-Fail
IH
to V
t
PF(MIN)
to VSO t
to V
t
PF(MAX)
0
300
10
0
ms
ms
ms
ms
35 200 ms
CAPACITANCE
(TA = +25°C)
PARAMETER SYMBOL MIN TYP MAX UNITS
Capacitance on All Input Pins CIN 10 pF
10 pF
Capacitance on IRQ, PWR, RST, and DQ Pins
C
IO
AC TEST CONDITIONS
OUTPUT LOAD
(Y) 50pF + 1TTL Gate Input: 1.5V
(W) 25pF + 1 TTL Gate
INPUT PULSE
LEVELS
0V to 3.0V for
5V operation
TIMING MEASUREMENT
REFERENCE LEVELS
Output: 1.5V
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INPUT PULSE RISE
AND FALL TIMES
5ns
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