Analog Devices Inc./Maxim Integrated DS1210N

Overview

DS1210N from Maxim Integrated is a nonvolatile controller IC that enables battery-backed CMOS RAM operation by providing automatic power-fail detection, write protection, and seamless VCC-to-battery switchover. It features 4.5V–4.74V VCC trip point (TOL=GND), <100nA battery current draw, and operates across –40°C to +85°C in an 8-pin PDIP package. It is used in industrial data loggers and real-time clock memory systems requiring guaranteed data retention during power loss.

For engineers reviewing the DS1210N datasheet, DS1210N pinout, DS1210N application, or DS1210N equivalent, key selection criteria include its dual-battery redundancy support, precise 20ns CE propagation delay, TOL-pin configurable power-fail threshold, CEO output behavior under brownout, and industrial-temperature-rated 8-pin PDIP packaging for legacy board compatibility.

Technical Context

The DS1210N integrates five core functions: (1) bidirectional low-drop (<0.3V) power-switching between VCCI and VBAT1/2; (2) precision comparator-based power-fail detection with two selectable thresholds (4.5–4.74V or 4.25–4.49V) set via the TOL pin; (3) conditional CEO output hold logic that delays write protection until CE returns high, preventing mid-cycle data corruption; (4) battery voltage self-test at power-up using a 2.0V threshold comparator; and (5) internal isolation switch enabling transparent redundant battery selection based on highest voltage.

Its architecture avoids external timing components and relies on low-leakage CMOS process technology to achieve sub-100nA quiescent battery drain while maintaining deterministic 2–125ms power-up recovery timing and 300µs VCC slew-rate response during power-down transitions.

Key Specifications

Pinout & Package

DS1210N is supplied in an 8-pin plastic dual in-line package (PDIP), 300 mil width, with through-hole mounting and RoHS-compliant lead finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar nonvolatile RAM controller applications.

Compared with MAX6900 and DS1230Y, the DS1210N offers unique flexibility in external SRAM selection, hardware-configurable brownout thresholds, and true dual-battery failover-making it optimal for industrial systems requiring long-term serviceability and deterministic power-loss response.

Availability

DS1210N is available at Aetrix Electronics and suitable for industrial data loggers, real-time clock memory backup, and factory automation PLC modules requiring stable component supply and long-lifecycle support.

Supply support for DS1210N includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for industrial, automotive, and communications applications.

The DS1210N belongs to Maxim's nonvolatile memory interface product line, engineered specifically to extend SRAM data retention during AC power interruptions without software intervention or external supervision.

FAQ

What is the function of the TOL pin on the DS1210N?

The TOL pin on the DS1210N selects the power-fail detection threshold: grounding TOL sets the VCC trip point to 4.50–4.74V, while connecting TOL to VCCO lowers it to 4.25–4.49V. This hardware-selectable range allows designers to match the DS1210N's brownout response to specific power supply tolerances without external components. The DS1210N uses this pin to configure its internal comparator reference, directly affecting when CEO is inhibited during voltage droop.

How does the DS1210N handle dual-battery redundancy?

The DS1210N incorporates an internal isolation switch that continuously monitors VBAT1 and VBAT2 voltages and automatically selects the higher one to power VCCO during backup mode. If the active battery drops below 2.0V, the DS1210N triggers a battery-fail warning and switches to the other battery transparently-no firmware or external logic is required. In single-battery use, VBAT2 must be grounded per DS1210N specifications.

What is the maximum load current the DS1210N can supply to SRAM in battery mode?

The DS1210N supports up to 50µA of average battery backup current (ICCO2) when VCCO = VBAT – 0.3V, sufficient for low-power CMOS SRAMs consuming ≤10µA typical. This rating ensures reliable operation with common 32kB–256kB industrial SRAMs. Exceeding ICCO2 risks undervoltage on VCCO and data corruption; designers must verify total RAM + peripheral load against this DS1210N limit.

Does the DS1210N require external components for basic operation?

No, the DS1210N requires no external resistors, capacitors, or timing components for core functionality. Its power-fail detection, CEO timing, battery switching, and self-test are fully integrated. Only passive decoupling (e.g., 0.1µF ceramic at VCCI) is recommended per Maxim guidelines. All configuration-including trip point and redundancy-is handled via the TOL, VBAT1, and VBAT2 pins, making the DS1210N a drop-in enabler for nonvolatile RAM systems.

What happens to CEO during a power-fail event when CE is low?

When a power-fail is detected and CE is low, the DS1210N holds CEO in its current state until CE returns high-ensuring the ongoing memory cycle completes before write protection engages. This prevents partial writes and data corruption. Once CE goes high, CEO is immediately driven low to inhibit further writes. This behavior is intrinsic to the DS1210N's design and does not require external latching or firmware coordination.