DS1338Z-18+T&R - I2C RTC with 56B NV SRAM | Analog Devices
MPN: DS1338Z-18+T&R ✓ Hoạt độngDS1338Z-18+T&R Tóm tắt
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.
Bộ thay thế dễ dàng lắp đặt cho DS1338Z-18+T&R — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với DS1338Z-18+T&R (cùng hình factor và footprint) — khác nhau ở Device Type, Package.
DS1338Z-33+T&R
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →DS1338Z-3+T&R
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →DS1338Z-18+
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
DS1338Z-18+T&R Thông số kỹ thuật
| 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 |
| Hộp | 8-pin SOIC |
| Package Width | 3.90 mm |
| Package Length | 0.154 inch (3.90 mm body width, as stated by DigiKey) |
Hướng dẫn cấu hình chân DS1338Z-18+T&R 0.154 inch (3.90 mm body width, as stated by digikey)
Cấu hình chân cho DS1338Z-18+T&R (0.154 inch (3.90 mm body width, as stated by digikey) gói). Số thứ tự chân, chức năng và sơ đồ kết nối được xác định trong tài liệu thông số kỹ thuật của nhà sản xuất. Tham khảo nó để biết footprint và hướng dẫn hàn chính xác.
Không có dữ liệu chân cụ thể sẵn có cho DS1338Z-18+T&R.
Tham khảo: tài liệu kỹ thuật cho cấu hình chân đầy đủ.
Ứng dụng tiêu biểu
DS1338Z-18+T&R phù hợp cho 6 Áp dụngs: 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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho DS1338Z-18+T&R — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | 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 |
Bảo phân biệt quan trọng
- Combines calendar timekeeping with retained configuration memory (vsDS1338Z-33+T&R)
- Uses a narrow two-wire serial interface (vsDS1338Z-3+T&R)
- Matches the established -18 core ordering option (vsDS1338Z-18+)
Ghi chú thiết kế
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.
Thông tin tuân thủ
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.