Texas Instruments BQ4010MA-85

Overview

BQ4010MA-85 from Texas Instruments is a nonvolatile 8 k × 8 (65,536-bit) SRAM with integrated lithium backup, 5 V operation, 85 ns access time, and automatic power-fail write-protection. It serves as a drop-in replacement for standard 28-pin DIP SRAMs in systems requiring data retention during power loss-such as industrial PLCs, medical data loggers, and utility metering.

For engineers reviewing the BQ4010MA-85 datasheet, BQ4010MA-85 pinout, BQ4010MA-85 application, or BQ4010MA-85 equivalent, key selection criteria include VPFD threshold (4.62 V), tCER recovery delay (120 ms max), 10-year data retention, and compatibility with industry-standard 64-Kb SRAM timing and address/data bus interfaces.

Technical Context

The BQ4010MA-85 integrates a CMOS SRAM core, power-fail detection circuitry monitoring VCC against VPFD = 4.62 V (typ), and an internal lithium coin cell. During valid VCC, it behaves identically to a standard 8-kword × 8-bit SRAM with CE/OE/WE control logic and full read/write timing compliance.

On VCC dropout below VPFD, it unconditionally enters write-protected mode: outputs go high-Z, inputs are ignored, and the lithium supply sustains memory contents. After VCC returns above VPFD, tCER enforces 120 ms of continued write-protection before resuming normal operation-ensuring processor stabilization.

Key Specifications

Pinout & Package

28-pin plastic dual-in-line package (PDIP), MA package type, 0.600-inch width, through-hole mounting. Pin 14 = VSS (ground), Pin 28 = VCC (5 V supply), with 13 address lines (A0–A12), 8 bidirectional data lines (DQ0–DQ7), and standard control inputs (CE, OE, WE).

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK11C88-85 and DS1230Y-120+, the BQ4010MA-85 delivers superior integration (no external battery circuitry), tighter VPFD matching for 5 V ±5% systems, and shorter tCER-reducing system boot latency while maintaining identical pinout and timing behavior.

Availability

BQ4010MA-85 is available at Aetrix Electronics and suitable for industrial data loggers, medical device memory backup, smart utility metering, and avionics configuration storage requiring stable component supply and long-term lifecycle support.

Supply support for BQ4010MA-85 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with over 50 years of innovation in high-reliability memory and interface solutions.

The BQ4010MA-85 belongs to TI's bq40xx nonvolatile SRAM family, engineered specifically for mission-critical data retention in industrial, medical, and infrastructure equipment where power continuity cannot be assumed.

FAQ

What is the guaranteed data retention period for the BQ4010MA-85?

The BQ4010MA-85 guarantees ≥10 years of data retention in the absence of external power, based on TI's characterization of the internal lithium cell's self-discharge rate (<0.5% per year pre-activation) and SRAM leakage performance at 25°C. This specification applies after the first application of VCC, which electrically connects the battery to the memory array.

Does the BQ4010MA-85 require external components to operate as a nonvolatile SRAM?

No, the BQ4010MA-85 requires no external components. Its integrated lithium cell, power-fail detection circuitry, and automatic switchover logic are fully self-contained. Only standard SRAM interface signals (VCC, VSS, A0–A12, DQ0–DQ7, CE, OE, WE) are needed-no external comparators, switches, or backup regulators are necessary.

How does the BQ4010MA-85 handle a power-fail event during an active write cycle?

If a write cycle is in progress when VCC falls below VPFD = 4.62 V (typ), the BQ4010MA-85 completes the current memory cycle before asserting write-protection. If completion exceeds tWPT (40–150 µs), write-protection activates immediately to prevent partial or corrupted data writes-ensuring atomicity of the last completed operation.

Is the BQ4010MA-85 pin-compatible with standard 64-Kb SRAMs like the HM62256?

Yes, the BQ4010MA-85 uses an industry-standard 28-pin DIP (MA package) with identical pinout, signal definitions, and timing parameters as the HM62256 and IS62C256. It supports the same address/data/control interface and operates transparently as a drop-in replacement-no PCB or firmware changes required.

What is the purpose of the tCER parameter in the BQ4010MA-85 datasheet?

tCER (Chip Enable Recovery time) is the 120 ms maximum delay after VCC rises above VPFD during which the BQ4010MA-85 remains in write-protected mode. This ensures the host processor has sufficient time to stabilize its clock, reset peripherals, and reinitialize memory controllers before normal SRAM access resumes-preventing spurious writes during boot.