MAXIM INTEGRATED PRODUCTS DS1602 Elapsed Time Counter Product Data Sheet
Summary
Measure precise real-time or elapsed time with this advanced dual 32-bit Real-Time Clock and Counter. Designed for embedded system developers, the DS1602 provides unparalleled timing accuracy, maintaining count data even during power failures by utilizing robust battery backup functionality. The device features low pin count serial communication and independently tracks time via both a continuous crystal oscillator and a voltage-powered counter. This guide details the complete operation, electrical specifications, communication protocols, and performance data necessary for integrating reliable, long-term timekeeping solutions into electronic circuits.
Page 1 Text Content
DS1602
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Elapsed Time Counter
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FEATURES PIN ASSIGNMENT § Two 32-bit counters keep track of real-time
RST VCC
and elapsed time
DQ X1
§ Counters keep track of seconds for over 125
years CLK X2
§ Battery powered counter counts seconds from GND VBAT the time battery is attached until VBAT is less
DS1602
than 2.5V
8-Pin DIP (300mil)
§ VCC powered counter counts seconds while VCC is above VTP and retains the count in the
absence of VCC under battery backup power RST VCC
§ Clear function resets selected counter to 0 DQ X1 § Read/write serial port affords low pin count
CLK X2
§ Maximum current drain of less than 1 µA
GND VBAT
from VBAT pin when serial port is disabled
DS1602
§ One byte protocol defines read/write, counter
8-Pin SOIC (208mil)
address and software clear function § 8-pin DIP or optional 8-pin SOIC
Package Dimension Information
§ Operating temperature range of -40°C to
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+85°C § Reduced performance operation down to
PIN DESCRIPTION
VCC = 2.5V
RST - Reset
§ Underwriters Laboratory (UL) recognized
CLK - Clock DQ - Data Input/Output GND - Ground X1, X2 - Crystal Inputs VBAT - + Battery Input VCC - +5V
DESCRIPTION The DS1602 is a real-time clock/elapsed time counter designed to count seconds when VCC power is applied and continually count seconds under battery backup power with an additional counter regardless of the condition of VCC. The continuous counter can be used to derive time of day, week, month, and year by using a software algorithm. The VCC powered counter will automatically record the amount of time that VCC power is applied. This function is particularly useful in determining the operational time of equipment in which the DS1602 is used. Alternatively, this counter can also be used under software control to record real-time events. Communication to and from the DS1602 takes place via a 3-wire serial port. A 1-byte protocol selects read/ write functions, counter clear functions and oscillator trim. A low cost 32.768k Hz crystal attaches directly to the X1 and X2 pins. If battery powered-only operation is desired, the VBAT pin must be grounded and the VCC pin must be connected to the battery.
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. 1 of 10 093002
Page Summary Contents For MAXIM INTEGRATED PRODUCTS DS1602 Elapsed Time Counter Product Data Sheet
Manual Details
| Brand | Maxim Integrated |
|---|---|
| Pages | 8 |
| File Size | 212.54 KB |
| Published | May 26, 2026 |
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Frequently Asked Questions
How does battery backup work on the DS1602?
When V is less than 2.5V, the unit enters battery backup mode. The continuous counter keeps running, and the serial port disables to conserve power.
What steps are necessary for battery-only operation?
To run solely on battery power, you must ground the V pin and connect that pin directly to the battery terminals.
How do I read or write data from the two counters?
Communication uses a 3-wire serial port. A protocol register is loaded first (using RST), which selects the target counter before data can be read or written.
What are the minimum required inputs and operational limits?
The device operates over an industrial temperature range of -40°C to +85°C, and uses a 32.768kHz low cost crystal attached to X1 and X2 pins.