DS1338C-18# - I2C RTC with 56-Byte NV RAM | Analog Devices
N.º de pieza: DS1338C-18# ✓ ActivoDS1338C-18# Descripción general
A real-time clock is a timekeeping integrated circuit that maintains calendar information independently of a system’s main processor. In the electronic-component hierarchy, an RTC belongs to clock and timing integrated circuits and provides a dedicated time base for data logging, control, communications, and embedded systems. Unlike a software clock calculated by a microcontroller, this RTC can continue tracking elapsed time while the host is reset, asleep, or disconnected from its main power rail.
The DS1338C-18# combines a serial RTC with 56 bytes of nonvolatile SRAM. The clock/calendar automatically adjusts the end-of-month date for months containing fewer than 31 days. Address and data transfer through the I2C interface, allowing the host processor to read calendar data and access the auxiliary SRAM over the same two-wire bus. This integration reduces the number of separate serial components required in compact embedded designs.
The verified product information identifies the part as an industrial-temperature, gull-wing terminal, 16-terminal SOP package. It is specified for use with I2C-compatible controllers and is suited to systems requiring persistent timestamps, alarm functions, periodic scheduling, or limited configuration storage. The nonvolatile SRAM provides 56 bytes for counters, calibration values, serial identifiers, operating flags, or other small records that must survive a reset and power loss.
Because the RTC communicates over a shared two-wire bus, correct pull-up resistor selection and bus timing are central to implementation. The host must also distinguish the RTC’s calendar registers from the SRAM addresses and preserve adequate decoupling near the device. Reviewing the DS1338C datasheet and the specific ordering suffix ensures that supply configuration, temperature grade, and package interpretation match the assembled board.
This product page combines verified distributor and manufacturer information, technical application guidance, parameter comparisons, and practical replacement considerations. It is intended to support component selection, schematic review, sourcing, and PCB design without substituting a generic RTC for a verified pin-compatible device.
Alternativas directas para DS1338C-18# — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con DS1338C-18# (mismo factor de forma y huella) — difiere en Package, Serial Interface, Device Type, Package Width, Product Type.
DS1338C-3#
✅ Sustitución directaConsulte el precio
Ver hoja de datos →DS1338C-33#
✅ Sustitución directaConsulte el precio
Ver hoja de datos →DS1339C-33#
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
DS1302Z+
✅ Sustitución directa ⚠️ Especificaciones sin verificarConsulte el precio
Ver hoja de datos →DS1338C-18# Especificaciones
| Product Type | Serial real-time clock and calendar with nonvolatile SRAM |
| Clock and Calendar Format | Full binary-coded decimal (BCD) |
| Serial Interface | I2C, 2-wire serial |
| Nonvolatile SRAM Capacity | 56 bytes |
| Calendar Coverage | Seconds, minutes, hours, day, date, month, and year |
| Automatic Month Adjustment | End-of-month date automatically adjusted for months with fewer than 31 days |
| Encapsulado | 16-SOIC (0.295 inch, 7.50 mm width) |
| Terminal Count | 16 terminals |
| Estilo de montaje | Gull wing |
| Package Shape | Rectangular |
| Temperature Grade | Industrial |
Guía de configuración de pines de DS1338C-18# rectangular
Configuración de pines para DS1338C-18# (encapsulado rectangular). La numeración de pines, las funciones y los diagramas de conexión se definen en la hoja de datos del fabricante. Consúltela para conocer el footprint exacto y las directrices de soldadura.
No hay datos detallados de patillaje disponibles para DS1338C-18#.
Consulte la hoja de datos para ver la configuración completa de patillas.
Aplicaciones típicas
DS1338C-18# es adecuado para 6 aplicacións: Industrial Data Logger, Remote Monitoring Equipment, Embedded Control System, Communication Gateway, Security and Access Control, Battery-Powered Instrumentation.
Industrial Data Logger
The DS1338C-18# fits an industrial data logger because it combines full BCD calendar registers with 56 bytes of nonvolatile SRAM in a 16-SOIC package. The host processor can timestamp measurements through the I2C interface and retain counters, calibration flags, or batch identifiers in the auxiliary SRAM. This separates time metadata from volatile controller memory so records remain traceable after a reset or power interruption. The industrial temperature-grade marking also aligns with equipment intended for controlled industrial environments, although the exact operating range must be confirmed from the manufacturer datasheet.
Recomendado
Remote Monitoring Equipment
The DS1338C-18# provides a dedicated time base for remote monitoring equipment where environmental samples or alarms must be associated with real calendar time. Its low-power RTC and 56 bytes of nonvolatile SRAM allow a controller to preserve a small event history, retry counter, or device status without relying on an external memory component. The I2C bus shares address and data lines, which simplifies the physical connection to the monitoring controller. Firmware should implement rollover handling and timestamp validation using the register behavior defined in the DS1338C datasheet.
Recomendado
Embedded Control System
The DS1338C-18# is suitable for embedded control systems that require calendar scheduling independently of the main microcontroller. Seconds, minutes, hours, day, date, month, and year registers provide a structured time reference, while automatic end-of-month adjustment reduces calendar-maintenance code. The 56-byte nonvolatile SRAM can hold configuration values that must persist across resets. Because the device communicates through I2C, pull-up resistors, bus capacitance, and pull-up voltage must be checked against the electrical limits in the manufacturer documentation.
Recomendado
Communication Gateway
The DS1338C-18# can support communication gateways that must attach accurate event times to messages, alarms, or diagnostic records. Its I2C interface avoids dedicating separate serial lines to the timekeeping function, and the 56-byte SRAM can retain a sequence number or communication state across resets. The 16-SOIC package is practical for compact boards where a larger parallel-interface RTC would be unnecessary. Designers should define how the host resolves time-synchronization conflicts between the RTC and an external network time source.
Recomendado
Security and Access Control
The DS1338C-18# is useful in access-control and security equipment where event logs must retain a valid timestamp through controller restarts. The BCD clock/calendar supplies structured date and time information, while the 56-byte nonvolatile SRAM can preserve a small audit counter, configuration checksum, or operating state. The I2C interface allows a low-pin-count implementation, although clock and calendar registers should be protected against unintended writes through appropriate firmware access controls. For certification-sensitive systems, verify the exact operating and reliability requirements separately.
Recomendado
Battery-Powered Instrumentation
The DS1338C-18# can support battery-powered instruments that need accurate event time without continuously running a microcontroller timer. Its dedicated real-time clock and 56-byte nonvolatile SRAM separate timekeeping and small persistent state from the host processor, potentially simplifying low-power control. The verified material identifies a low-power design and industrial temperature grade, but no numerical current consumption was supplied. Power-budget analysis must therefore use the manufacturer datasheet values and include the current required by the backup supply path.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para DS1338C-18# — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | DS1338C-3# | DS1338C-33# | DS1339C-33# | DS1302 |
|---|---|---|---|---|---|
| Package | 16-SOIC (0.295 inch, 7.50 mm width) | 16-pin NSOIC | 16-SOIC | 16-SOIC | 16-SOIC |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
Diferenciadores clave
- Integrated calendar clock and persistent auxiliary memory (frente a DS1339C-33#)
- Direct same-family pin-compatible sourcing path (frente a DS1338C-3#)
- Compact 16-SOIC implementation (frente a DS1338C-33#)
Notas de diseño
Place the DS1338C-18# near the system I2C controller and route the SDA and SCL traces as a compact, matched pair. Keep the device away from noisy switching nodes and provide local supply decoupling as specified in the manufacturer datasheet. The supplied verified data does not include capacitor values, so capacitor selection must follow the official recommended application circuit rather than an assumed generic value.
Account separately for normal operation and backup-supply current because the RTC may continue timing when the primary system supply is removed. The verified snippets confirm low-power operation but provide no numerical current limits, so use the DS1338C datasheet values in the battery and standby budget. Do not select backup capacitance or leakage assumptions without the manufacturer’s minimum-battery-life guidance.
Do not assume that any I2C RTC is interchangeable with DS1338C-18#. Verify the complete pin map, device address, alarm and square-wave outputs, interrupt behavior, backup-supply threshold, and BCD register implementation against the manufacturer datasheet. The supplied data confirms a 16-SOIC package and I2C architecture, but it does not include the full pin table, so an unqualified substitution can cause address conflicts or persistent-state failures.
Size I2C pull-ups for the actual bus voltage, capacitance, clock rate, and number of connected devices. Excessive pull-up current can increase rise-time violations, while insufficient pull-up strength can prevent valid high levels at the DS1338C-18#. Include bus capacitance from PCB traces and other peripherals when checking timing, and consult the manufacturer’s I2C timing limits before increasing the clock frequency.
Información de cumplimiento
The supplied verified snippets mention industrial temperature grade and cross-reference comparisons involving RoHS and REACH, but they do not provide explicit compliance conclusions for DS1338C-18#. Compliance fields are therefore left unknown rather than inferred.
