DS1338C-33#T&R - 3.3V I2C RTC with 56B NV RAM | ADI
N.º de pieza: DS1338C-33#T&R ✓ ActivoDS1338C-33#T&R Descripción general
A real-time clock, or RTC, is a clock-and-timing IC that maintains time independently of the host processor or system clock. Its place in the broader hierarchy is RTC → serial RTC → clock and timing IC → integrated circuit. The DS1338 stores its time and calendar data in binary-coded decimal form, automatically adjusts the end-of-month date for months with fewer than 31 days, and supports leap-year information through its clock/calendar functions.
The principal feature of the DS1338C-33#T&R is the combination of a complete calendar clock and 56 bytes of battery-backed nonvolatile memory in one serial device. The I2C interface transfers both address and data over two wires, reducing the pin and routing burden compared with a parallel RTC. Additional documented functions include a square-wave output, leap-year handling, and automatic month-end adjustment. The specified operating supply range is 3 V to 5.5 V, while the backup battery input accepts 1.3 V to 3.7 V.
The device is designed for low-power timekeeping, with a verified timekeeping current range of 125 µA to 200 µA. Its backup supply allows the clock and calendar, as well as information retained in the nonvolatile memory, to continue operating when the main supply is absent, subject to the device-specific backup implementation. The 16-pin SOIC package supports conventional surface-mount assembly and provides separate access for serial data, timekeeping crystals, supplies, reset, and square-wave functionality, although the supplied source excerpts do not include the complete pin map.
Typical uses include industrial embedded systems, data-logging equipment, metering products, medical instruments, and networked embedded controllers. The 56-byte NV SRAM is useful for small pieces of persistent information such as counters, calibration flags, calibration offsets, event counters, or configuration records. The 3.3 V configuration is particularly appropriate for systems whose logic rails operate at 3.3 V, while the 3 V to 5.5 V main supply range provides flexibility across mixed-voltage equipment.
When designing around this RTC, budget for the exact crystal load capacitance and layout recommended by the manufacturer, and verify startup behavior across the complete temperature range. The I2C pull-up network must tolerate the active bus voltage, while the backup cell or supply path requires careful leakage control to preserve retained data. Because the supplied excerpts do not publish a complete verified pinout, timing accuracy, oscillator trim range, or all lifecycle and environmental limits, engineers should confirm those details in the manufacturer datasheet before release.
This page combines verified manufacturer and distributor information, price and sourcing details as of 2026-10-29, same-package alternative assessment, and application-focused design guidance. It also separates documented facts from unverified parameters so that procurement and engineering decisions can be made without treating unsupported specifications as guaranteed.
Alternativas directas para DS1338C-33#T&R — 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-33#T&R (mismo factor de forma y huella) — difiere en Package, Serial Interface.
DS1338C-3#
✅ Sustitución directaConsulte el precio
Ver hoja de datos →DS1338C-18
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
DS1339C-33#
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
DS1340C-33#T&R
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
DS1338C-33#T&R Especificaciones
| Product Type | Serial real-time clock and calendar with 56 bytes of NV SRAM |
| Nominal Supply Voltage | 3.3 V |
| Main Supply Voltage Range | 3 V to 5.5 V |
| Battery Backup Voltage Range | 1.3 V to 3.7 V |
| Timekeeping Current Consumption | 125 µA to 200 µA |
| Serial Interface | I2C, 2-wire |
| Nonvolatile RAM Capacity | 56 bytes |
| Calendar Format | Full binary-coded decimal (BCD) |
| Tracked Time Fields | Seconds, minutes, hours, day, date, month, and year |
| Month-End Adjustment | Automatic for months with fewer than 31 days |
| Leap-Year Support | Yes |
| Square-Wave Output | Yes |
| Encapsulado | 16-pin SOIC, 0.295-inch body width, 7.50 mm width |
| Tipo de montaje | Surface mount |
| Ordering Format | Tape and reel |
Guía de configuración de pines de DS1338C-33#T&R 16-pin soic, 0.295-inch body width, 7.50 mm width
Configuración de pines para DS1338C-33#T&R (encapsulado 16-pin soic, 0.295-inch body width, 7.50 mm width). 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-33#T&R.
Consulte la hoja de datos para ver la configuración completa de patillas.
Aplicaciones típicas
DS1338C-33#T&R es adecuado para 6 aplicacións: Battery-Backed Industrial Data Logger, Smart Utility Metering, Medical Device Time Stamping, Industrial Control and Automation Node, Networked Embedded Equipment, IoT Sensor Node.
Battery-Backed Industrial Data Logger
The DS1338C-33#T&R fits battery-backed industrial data loggers that must preserve timestamps after a power interruption. Its I2C interface connects efficiently to a 3.3 V microcontroller, while the 56-byte NV SRAM can hold counters, a sample index, or a compact calibration offset. The documented 3 V to 5.5 V operating range and 1.3 V to 3.7 V backup range support systems in which the main rail is switched while the backup source remains available. Its 125 µA to 200 µA timekeeping current is a useful baseline, but the complete battery-life calculation must also include pull-ups, the crystal network, and leakage paths.
Recomendado
Smart Utility Metering
DS1338C-33#T&R is suitable for electricity, water, gas, and environmental meters requiring event timestamps and a limited persistent data area. The 56-byte NV RAM can preserve a limited number of counters, calibration flags, or status bytes without using nonvolatile flash, while the BCD calendar automatically handles month-end date changes. With a 3.3 V system supply and a 125 µA to 200 µA timekeeping-current range, it supports low-duty-cycle metering. Designers should verify the meter's required accuracy, temperature range, oscillator tolerances, and battery backup current directly in the manufacturer documentation before production.
Recomendado
Medical Device Time Stamping
The DS1338C-33#T&R can provide persistent event timestamps in connected medical and diagnostic equipment where maintaining time through a main-power interruption is important. Its I2C bus reduces connection requirements, and the 56 bytes of NV SRAM are appropriate for small counters or configuration markers rather than bulk patient data. The 3.3 V configuration is suitable for common embedded rails, and the backup input can maintain calendar information when the primary supply is unavailable. Medical designs must additionally verify accuracy, safety requirements, operating temperature, retention behavior, and the applicable product qualification; those details are not supplied in the verified excerpts.
Recomendado
Industrial Control and Automation Node
DS1338C-33#T&R supports industrial control nodes that need local event time, periodic scheduling, and persistent counters. The square-wave output can serve as a timing reference where the host system needs a predictable cadence, while the RTC maintains calendar information independently of processor downtime. The 3 V to 5.5 V supply range and 3.3 V nominal configuration provide compatibility with embedded industrial controllers, and the two-wire I2C interface simplifies connection to sensors and interface ICs. Factory designs should confirm the full temperature range, startup timing, oscillator tolerance, and backup-source leakage to ensure fit for harsh operating environments.
Recomendado
Networked Embedded Equipment
DS1338C-33#T&R is useful in routers, gateways, and other networked embedded products that log events or maintain schedules across power cycles. The RTC can timestamp boot events and retain small counters in its 56-byte NV RAM, while I2C provides a compact connection to the main processor. Its 3.3 V configuration aligns with common communications-controller logic rails, and the specified 125 µA to 200 µA timekeeping current supports low-power operation. For equipment exposed to network timing requirements, engineers should compare the RTC accuracy and calibration behavior with the system clock and define which source is authoritative during boot and recovery.
Recomendado
IoT Sensor Node
The DS1338C-33#T&R fits IoT sensor nodes that must timestamp samples and retain a small amount of state between battery changes or resets. Its I2C interface is well suited to a low-pin-count microcontroller, and the 56-byte NV RAM can hold a sequence number, interval setting, or calibration value. The 3 V to 5.5 V main range and 1.3 V to 3.7 V backup range permit flexible supply arrangements, while the documented 125 µA to 200 µA timekeeping current helps control standby demand. Deployment designs must account for the backup cell's self-discharge, pull-up leakage, radio activity windows, and the RTC's accuracy across its intended temperature range.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para DS1338C-33#T&R — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | DS1338C-3# | DS1338C-18 | DS1339C-33# | DS1340C-33#T&R |
|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 16-pin SOIC, 7.50 mm width | 16-pin NSOIC | 16-pin SOIC | 16-pin SOIC | 16-pin SOIC |
| Nominal Supply Voltage | 3.3 V | 3 V | 1.8 V | 3.3 V | 3.3 V |
Diferenciadores clave
- Exact 3.3 V family configuration with a broad verified main-supply range (frente a DS1338C-18)
- Documented 56-byte NV SRAM alongside the BCD clock/calendar (frente a DS1339C-33#)
- Complete verified operating and backup supply information (frente a DS1340C-33#T&R)
- Square-wave timing output included in the documented feature set (frente a DS1338C-3#)
Notas de diseño
Place the RTC crystal and its associated load network close to the DS1338C-33#T&R crystal pins, following the manufacturer layout and grounding guidance. Keep high-current switching paths away from the oscillator area to reduce injected noise that can degrade timekeeping. The supplied excerpts do not identify the exact crystal pins, load capacitance, or recommended PCB geometry, so the official DS1338 datasheet and application guidance must control the final layout rather than inferred pin functions.
Validate both the main and backup paths across all normal and fault states. The verified main supply range is 3 V to 5.5 V and the backup range is 1.3 V to 3.7 V. Prevent the backup source from being driven above its allowed range and prevent main-rail leakage from back-feeding the backup domain. Also include I2C pull-up leakage, the crystal circuit, and external load switches in the standby-current budget; the stated 125 µA to 200 µA is timekeeping current, not the complete system consumption.
Design the I2C pull-ups for the active bus voltage and the worst-case total bus capacitance rather than using an arbitrary resistor value. The two-wire interface reduces routing requirements, but a common clock/data ground and short traces remain important for signal integrity. Confirm the device's official I2C address, address pins, operating frequency, and any pull-up requirements from the datasheet because those values are not present in the verified source excerpts.
Do not substitute DS1338C-18 for DS1338C-33#T&R merely because both use a 16-pin package. The family suffixes indicate different nominal voltage configurations, and the -18 option is 1.5 V below the target 3.3 V configuration. Likewise, do not treat DS1338U or DS1338Z package variants as drop-in replacements: the supplied comparisons identify smaller or narrower packages. Always confirm the footprint, pin assignment, voltage, accuracy, and backup behavior before approving a substitution.
Información de cumplimiento
The verified excerpts mention RoHS details for related comparisons but do not provide an explicit compliance statement for DS1338C-33#T&R. The component is not presented as an automotive-qualified part in the supplied data.
