The iButton is a high-performance, rugged, and rewritable non-volatile data storage device. It features 4096 bits of read/write non-volatile memory, 256-bit scratchpad, real-time clock/calendar, interval timer, programmable cycle counter, programmable alarms, write protect, programmable expiration date, a clock accuracy of ±2 minutes/month at 25°C, an operating temperature range of -40°C to +70°C, and over 10 years of data retention.
The DS1994 iButton is a rugged, parasite‑powered data carrier that combines 4 kb of non‑volatile SRAM with a 64‑bit laser‑etched ROM, a 256‑bit scratchpad buffer, and integrated time‑keeping functions (real‑time clock, interval timer, cycle counter). It communicates over the 1‑Wire bus using a single data line and supports programmable alarms, write‑protect, and expiration features.
Physical specifications include a 16 mm stainless‑steel case (F5 MicroCan) weighing 3.3 g, operating from –40 °C to +70 °C, with a voltage range of –0.5 V to +7 V. Electrical characteristics detail logic‑high/low thresholds, capacitance up to 800 pF, and timing parameters for reset, presence detect, and data transfer.
| Memory Capacity | 4096 bits (4 kb) SRAM |
|---|---|
| Scratchpad Size | 256 bits |
| ROM Size | 64 bits (laser‑etched) |
| Operating Temperature Range | -40 °C to +70 °C |
| Clock Accuracy | ±2 minutes per month at 25 °C |
| Data Retention | Over 10 years at 25 °C |
| Package Weight | 3.3 g (F5 MicroCan) |
| Maximum Voltage on Pin | -0.5 V to +7.0 V |
The DS1994 provides 4096 bits (4 kb) of non‑volatile SRAM memory.
The device operates from –40 °C up to +70 °C.
Pins may tolerate voltages between –0.5 V and +7.0 V relative to ground.