Analog Devices Inc./Maxim Integrated DS1239-10

Overview

DS1239-10 from Maxim Integrated (now Analog Devices) is a power supply supervisor and microprocessor manager IC designed for AC/DC power sequencing control, nonvolatile SRAM backup, and orderly system reset in embedded systems. It provides 10% VCC monitoring accuracy, active-low RST output, PSI/PSO power control interface, and consumes <100 nA battery current during backup mode. Used in keyboard-initiated power-up/down systems with optically isolated SCR drivers.

For engineers reviewing the DS1239-10 datasheet, DS1239-10 pinout, DS1239-10 application, or DS1239-10 equivalent, key selection considerations include its VCC=+5V supervision threshold tolerance, PSI/PSO timing parameters (tPSI=200 ms min), battery-backed memory write-protection behavior, and compatibility with DS1236 NMOS-mode systems where RC/RST pins are replaced by PSI/PSO.

Technical Context

The DS1239-10 implements dual-supply monitoring (VCC and VBAT), with internal logic that asserts RST when VCC falls below 4.5 V (10% under 5 V) and activates PF (Power Fail) to warn of impending brownout. Its PSI input initiates power-up sequencing by enabling PSO to source up to 10 mA to an external SCR gate, sustaining output for up to 500 ms until VCC reaches VBAT or timeout.

Unlike standard reset supervisors, DS1239-10 integrates memory control functions: CEI/CEO enable/disable SRAM access during power transitions, WC/SC manages sleep mode entry, and VCCO supplies switched +3 V to CMOS SRAM during battery backup - all coordinated with NMI assertion and PBRST-driven reset recovery.

Key Specifications

Pinout & Package

Available in 16-pin plastic DIP (300-mil) and 16-pin SOIC (300-mil) packages. Both share identical pin mapping and thermal characteristics per Maxim DS1239 mechanical drawings.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power management and nonvolatile memory control applications.

Compared with DS1239-5 and MAX690, the DS1239-10 uniquely combines precise power sequencing initiation (PSI/PSO), battery-backed SRAM control (VCCO/CEI/CEO), and dual-polarity PF signaling - making it irreplaceable in keyboard-controlled, nonvolatile-memory-centric designs.

Availability

DS1239-10 is available at Aetrix Electronics and suitable for keyboard-initiated power management, nonvolatile SRAM backup systems, handheld stop-mode operation, and microprocessor brownout recovery requiring stable component supply across extended production lifecycles.

Supply support for DS1239-10 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, computing, and communications applications.

The DS1239-10 belongs to Maxim's MicroManager family - engineered specifically for integrated power sequencing, memory backup, and intelligent reset control in resource-constrained embedded systems.

FAQ

What is the primary function of the DS1239-10 in a microprocessor system?

The DS1239-10 serves as an integrated power supervisor and microprocessor manager. It controls power-up/shutdown sequencing via PSI/PSO, monitors VCC for 10% tolerance violations, asserts RST and PF signals during transients, backs up SRAM using VCCO from VBAT, and supports keyboard-initiated power control - all within a single 16-pin package. The DS1239-10 replaces discrete reset ICs, power switches, and memory controllers in compact embedded designs.

How does the DS1239-10 handle power failure warning and system reset?

The DS1239-10 uses dual PF outputs (active-high and active-low) to signal impending power failure to the microprocessor via NMI before asserting RST. When VCC drops below 4.5 V, PF activates immediately, giving software time to save critical data; RST follows after a fixed delay to ensure clean shutdown. This two-stage response is built into the DS1239-10's internal state machine and requires no external timing components.

Can the DS1239-10 be used with a 3.3 V microprocessor system?

No - the DS1239-10 is specified for +5 V VCC operation and 10% monitoring centered at 5 V (4.5–5.5 V range). Its RST, PF, and PSO outputs are TTL/CMOS compatible with 5 V logic families. Using it with a 3.3 V system would violate absolute maximum ratings and cause incorrect threshold detection. For 3.3 V systems, consider the DS1233 or MAX6315 series instead of DS1239-10.

What is the role of the WC/SC pin on the DS1239-10?

The WC/SC (Wake-Up Control/Sleep Control) pin on the DS1239-10 enables low-power "stop mode" in battery-operated handheld devices. When asserted, it halts the microprocessor clock and places the DS1239-10 into a minimal-current state while maintaining VCCO to preserve SRAM contents. The DS1239-10 wakes on PSI, IN, or PBRST events - making it ideal for intermittent-sensing applications like portable meters or wearables.

Is the DS1239-10 pin-compatible with the DS1236?

The DS1239-10 is functionally identical to the DS1236 in NMOS mode except for two pin replacements: RC is replaced by PSI, and RST is replaced by PSO. All other pins (including VCC, GND, VBAT, PF, NMI, CEI, CEO, ST, IN, PBRST) retain identical functions and positions. Therefore, DS1239-10 is a drop-in replacement for DS1236 in designs where PSI/PSO power control is desired over RC/RST reset generation.