DS1338Z-18+T&R - I2C RTC with 56B NV SRAM | Analog Devices
Teilenummer: DS1338Z-18+T&R ✓ AktivDS1338Z-18+T&R Übersicht
A real-time clock is a clock-and-timing integrated circuit that preserves calendar time independently of the main processor clock. The DS1338 family belongs to the RTC and clock-and-timing hierarchy, where an RTC supplies seconds, minutes, hours, day, date, month, and year information. Its integrated nonvolatile memory allows a host controller to retain operating parameters without adding a separate memory component.
The principal features visible in the manufacturer documentation include full BCD clock and calendar data, automatic adjustment for months with fewer than 31 days, serial address and data transfer, and 56 bytes of NV SRAM. The I2C interface reduces the number of signal lines required when compared with a parallel RTC, while the narrow SOIC-8 package supports conventional surface-mount PCB assembly.
The DS1338 separates calendar management from the host processor by maintaining time whenever the system is powered by an appropriate backup supply. Calendar fields include seconds, minutes, hours, day, date, month, and year. The automatic month-end adjustment reduces firmware complexity because the device accounts for variable month lengths rather than requiring the controller to implement every calendar correction itself.
Typical uses include industrial controllers, data loggers, metering equipment, embedded instrumentation, battery-backed appliances, and connected products that need timestamps. The 56-byte NV SRAM can retain configuration, counters, calibration values, or diagnostic history, subject to the device's operating and retention limits documented by the manufacturer.
Designers should place the I2C pull-up resistors and backup-capacitor network according to the manufacturer datasheet, maintain the required logic levels and timing, and avoid assuming that the DS1338's NV SRAM has unlimited endurance. Firmware should detect and recover from invalid BCD or oscillator-start conditions where reliability is important.
This product page combines the verified manufacturer description with distributor packaging, inventory, and pricing data, plus practical guidance covering I2C implementation, backup behavior, calendar handling, and component selection. It is intended to help engineers find the correct 8-SOIC ordering code and distinguish the RTC's digital functionality from its electrical operating limits.
Drop-in-Alternativen für DS1338Z-18+T&R – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Varianten dieser Serie
Modelle derselben Serie, die drop-in-kompatibel sind mit DS1338Z-18+T&R (gleiche Bauform und Footprint) – abweichend in Device Type, Package.
DS1338Z-33+T&R
✅ Drop-InPreis auf Anfrage
Datenblatt ansehen →DS1338Z-3+T&R
✅ Drop-InPreis auf Anfrage
Datenblatt ansehen →DS1338Z-18+
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
DS1338Z-18+T&R Technische Daten
| Device Type | 1 serial real-time clock and calendar |
| Clock/Calendar Format | 1 full binary-coded decimal (BCD) clock/calendar |
| Calendar Fields | 7 fields: seconds, minutes, hours, day, date, month, and year |
| Nonvolatile SRAM | 56 bytes |
| Serial Interface | 1 I2C interface |
| Bus Width | 2 wires |
| Month-End Adjustment | 1 automatic adjustment for months with fewer than 31 days |
| Gehäuse | 8-pin SOIC |
| Package Width | 3.90 mm |
| Package Length | 0.154 inch (3.90 mm body width, as stated by DigiKey) |
DS1338Z-18+T&R 0.154 inch (3.90 mm body width, as stated by digikey) Pinbelegungsleitfaden
Pinbelegung für DS1338Z-18+T&R (0.154 inch (3.90 mm body width, as stated by digikey)-Gehäuse). Pin-Nummerierung, Funktionen und Anschlussdiagramme sind im Herstellerdatenblatt definiert. Entnehmen Sie diesem den genauen Footprint und Lötrichtlinien.
Keine detaillierten Pinbelegungsdaten verfügbar für DS1338Z-18+T&R.
Siehe die Datenblatt für die vollständige Pin-Konfiguration.
Typische Anwendungen
DS1338Z-18+T&R ist geeignet für 6 Anwendungs: Industrial Data Loggers, Battery-Backed Metering Equipment, Embedded Instrumentation, IoT Gateways and Connected Products, Battery-Powered Appliances, Communications and Access-Control Equipment.
Industrial Data Loggers
DS1338Z-18+T&R suits industrial data loggers that must attach timestamps to recorded measurements even when the main controller resets. The device provides a full BCD clock/calendar with seconds, minutes, hours, day, date, month, and year, while its 56-byte NV SRAM can retain sampling intervals, calibration flags, counters, or a limited event record. The two-wire I2C interface limits bus wiring, and the 8-SOIC package is practical for compact controller boards. Firmware should read the RTC through its device address and validate calendar values before recording them. The final temperature, supply-voltage, and accuracy requirements must be checked against the manufacturer datasheet for the deployed industrial environment.
Empfohlen
Battery-Backed Metering Equipment
DS1338Z-18+T&R can support metering equipment that must retain event time and limited operating data between main-power interruptions. Its full BCD clock/calendar provides a structured time record, and the 56-byte NV SRAM offers a compact place to retain counters, calibration identifiers, or reset-related flags. Because address and data use the I2C bus, the RTC can share a two-wire connection with other serial peripherals and reduce connector demand. The 8-SOIC format supports standard surface-mount assembly. A metering design must also provide the backup network and logic levels specified by the Analog Devices datasheet, and should budget for the NV SRAM's documented write endurance rather than treating it as unlimited flash storage.
Empfohlen
Embedded Instrumentation
The DS1338Z-18+T&R is appropriate for embedded instrumentation that must display or report the date and time while retaining a small amount of setup information. The seven calendar fields map directly to a full BCD clock/calendar, allowing the host processor to convert or format time without implementing leap-year and month-length bookkeeping alone. The 56-byte NV SRAM can preserve instrument configuration between power cycles. Its two-wire I2C connection also helps limit pin usage on compact control boards, while the 3.90 mm-wide 8-SOIC package remains easy to route alongside a microcontroller. Designers should account for oscillator startup and accuracy requirements, then use the manufacturer datasheet to confirm supply limits and environmental ratings for laboratory or field equipment.
Empfohlen
IoT Gateways and Connected Products
DS1338Z-18+T&R can supply local timekeeping for an IoT gateway when network time may be unavailable or when events must retain a local timestamp. The device maintains a full BCD clock/calendar and offers 56 bytes of NV SRAM for compact configuration or event metadata. Its two-wire I2C interface is useful in connected products because it allows the RTC to share a serial bus with sensors or memory, and the 8-SOIC package is suitable for automated surface-mount assembly. Firmware should synchronize to a trusted network clock when possible, retain the last valid RTC value, and detect implausible calendar states after power restoration. The designer must verify the backup-supply arrangement, oscillator tolerance, and operating-temperature range before using the part in outdoor equipment.
Empfohlen
Battery-Powered Appliances
DS1338Z-18+T&R is suitable for battery-powered appliances that need to remember elapsed events or operating history during main-power loss. The RTC maintains calendar information independently of the processor's main timing resources, while the 56-byte NV SRAM can preserve a small number of counters, fault flags, or configuration values. A two-wire I2C link keeps the interface compact, and the 8-SOIC package permits conventional PCB placement. For a low-power appliance, firmware should avoid unnecessary polling and disable or manage peripheral functions according to the device documentation. The backup capacitor, supply sequencing, and minimum operating voltage must be designed exactly as specified by the manufacturer, since those details determine how long time and SRAM data remain available.
Empfohlen
Communications and Access-Control Equipment
DS1338Z-18+T&R can support communications and access-control products that associate records with a calendar timestamp. The full BCD clock/calendar provides seconds through year, and the 56-byte NV SRAM can hold a short event index or configuration snapshot. The two-wire I2C interface is well suited to a compact embedded controller, while the 8-SOIC package allows reuse of an existing narrow-SOIC footprint. Systems should synchronize the RTC to an external reference where accuracy requirements are stringent and should handle invalid calendar data following a prolonged unpowered interval. The backup source, oscillator accuracy, I2C timing, and reset behavior must follow the official Analog Devices datasheet, and security-sensitive designs should not rely on the RTC's time value as an anti-tamper mechanism.
Empfohlen
Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für DS1338Z-18+T&R – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | DS1338Z-33+T&R | DS1338Z-3+T&R | DS1338Z-18+ |
|---|---|---|---|---|
| Package | 8-SOIC, 3.90 mm wide | SOIC-narrow-8 | 8-SOIC | 8-SOIC |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Device Function | I2C real-time clock/calendar with NV SRAM | DS1338Z-family real-time clock | DS1338Z-family real-time clock | I2C real-time clock/calendar with 56-byte NV SRAM |
| Voltage-Option Suffix | -18 | -33 | -3 | -18 |
| Delivery Format | Tape & Reel | Tape & Reel | Tape & Reel | Orderable designation without T&R suffix |
Wichtigste Unterscheidungsmerkmale
- Combines calendar timekeeping with retained configuration memory (vs. DS1338Z-33+T&R)
- Uses a narrow two-wire serial interface (vs. DS1338Z-3+T&R)
- Matches the established -18 core ordering option (vs. DS1338Z-18+)
Designhinweise
Design the main and backup supplies from the DS1338 manufacturer datasheet before fixing capacitor values or switching components. The verified excerpts establish that the device supports battery-backed operation but do not provide its minimum operating voltage, backup threshold, or supply current. Confirm those limits in the official PDF, then validate that the backup source can maintain the RTC and its 56-byte NV SRAM long enough for the application's expected power interruption.
Place the DS1338 close to the I2C controller and route SDA and SCL as short, clean traces. The two-wire interface reduces pin count, but excessive capacitance or long branches can still distort clock edges and violate timing. Use the pull-up values and bus capacitance permitted by the manufacturer data, keep ground return paths continuous, and avoid routing the RTC clock and data beneath noisy switching nodes.
Do not treat the 56-byte NV SRAM as unlimited nonvolatile storage. Budget writes deliberately, avoid rewriting unchanged values on every polling cycle, and preserve data during unexpected resets. Firmware should also validate the full BCD calendar after power restoration because an uninitialized or interrupted backup interval may leave implausible time and date values that require recovery through the host controller.
Apply the manufacturer's I2C timing, pull-up, and voltage-level guidance for the complete bus rather than only at the DS1338. Account for every device connected to SDA and SCL when calculating the effective pull-up resistance and bus capacitance. If the RTC sits on a long cable or a separate board segment, add appropriate buffering rather than assuming that the two-wire interface will remain reliable at low speed across the full interconnect.
Compliance-Informationen
The supplied verified results did not provide authoritative compliance declarations for this ordering code. AEC-Q100 is not applicable to the RTC function; an automotive qualification grade would require a specifically qualified orderable part and supporting manufacturer data.