Texas Instruments BQ2204ASNTR

Overview

BQ2204ASNTR from Texas Instruments is a CMOS SRAM nonvolatile controller unit that converts up to four banks of standard CMOS SRAM into battery-backed nonvolatile memory. It provides power-fail detection (VPFD = 4.62 V typical), conditioned chip-enable outputs (CECON1–CECON4), and automatic switching between two 3V primary backup cells (BC1/BC2) with <10 ns CE propagation delay, used in industrial data-logging systems requiring persistent memory during AC loss.

For engineers reviewing the BQ2204ASNTR datasheet, BQ2204ASNTR pinout, BQ2204ASNTR application, or BQ2204ASNTR equivalent, key selection criteria include its 5V primary supply operation with THS-selectable 5%/10% tolerance thresholds, VOUT-controlled SRAM write-protection timing (tWPT = 100 µs typ), and hardware-based 2-input address decoding (A/B) for bank selection without firmware overhead.

Technical Context

The BQ2204ASNTR implements a precision comparator-based power-fail detection circuit with threshold select (THS) that sets VPFD at 4.62 V (THS = VSS) or 4.37 V (THS = VCC). It integrates an internal analog switch to route VOUT to BC1 or BC2 based on voltage comparison with VBSO = 0.4 V typical, enabling sequential battery use.

During power-down, CECON outputs are forced high within tWPT = 100 µs after VCC falls below VPFD, unconditionally write-protecting SRAM. During power-up, CECON outputs remain inactive for tCER = 120 ms max after VCC exceeds VPFD, independent of CE input, ensuring processor stabilization before memory access resumes.

Key Specifications

Pinout & Package

Package: 16-pin SOIC (D), RoHS-compliant, moisture sensitivity level 2 (260°C reflow, 1 year floor life), tape-and-reel packaging (2500 units/reel).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX690TCSA+ and DS1230Y-100+, the BQ2204ASNTR uniquely supports four independently controlled SRAM banks, programmable VPFD via THS, and automatic dual-battery switchover-enabling scalable, long-life, field-serviceable nonvolatile memory architectures.

Availability

BQ2204ASNTR is available at Aetrix Electronics and suitable for industrial data loggers, medical device memory backup, point-of-sale terminals, and programmable logic controllers requiring stable component supply across extended product lifecycles.

Supply support for BQ2204ASNTR 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The BQ2204ASNTR belongs to TI's legacy battery-management and nonvolatile memory controller product line, designed specifically to enable cost-effective, firmware-free SRAM persistence in mission-critical power-loss scenarios.

FAQ

What is the function of the THS pin on the BQ2204ASNTR?

The THS pin on the BQ2204ASNTR selects the power-fail detection threshold: when tied to VSS, VPFD = 4.62 V (5% supply tolerance); when tied to VCC, VPFD = 4.37 V (10% tolerance). It must be hard-wired to VSS or VCC-floating causes undefined behavior. This configuration allows one BOM to serve both tight and relaxed supply regulation requirements without redesigning the BQ2204ASNTR circuit.

How does the BQ2204ASNTR manage two backup batteries (BC1 and BC2)?

The BQ2204ASNTR continuously compares BC1 and BC2 voltages and switches VOUT to the higher cell only when the difference exceeds VBSO = 0.4 V. It defaults to BC1 at power-on and transitions to BC2 only if BC1 depletes sufficiently. This ensures optimal utilization of both 3V primary cells and enables hot-swap replacement without system interruption-critical for BQ2204ASNTR deployments in unattended equipment.

What happens to SRAM access during the BQ2204ASNTR power-up recovery period?

During power-up, the BQ2204ASNTR holds CECON1–CECON4 inactive for tCER = 120 ms maximum after VCC crosses VPFD, regardless of the CE input state. This forces all controlled SRAM banks into write-protected mode until the host processor stabilizes. The BQ2204ASNTR ensures no spurious writes occur during CPU reset, preserving data integrity without requiring software coordination.

Can the BQ2204ASNTR support more than four SRAM banks?

No-the BQ2204ASNTR provides exactly four conditioned chip-enable outputs (CECON1–CECON4) and a 2-bit decoder (A/B inputs), limiting it to four SRAM banks. To scale beyond four banks, multiple BQ2204ASNTR devices must be used with hierarchical address decoding. Each BQ2204ASNTR operates independently, so bank count expansion requires additional PCB area and interconnect but retains identical timing and protection behavior per group of four.

What is the maximum load current supported by the BQ2204ASNTR VOUT pin?

The BQ2204ASNTR VOUT pin delivers up to 160 mA when VOUT > VCC − 0.3 V, sufficient to power the VCC pins of multiple low-power CMOS SRAM devices (e.g., four 62256-style 32K×8 SRAMs drawing ~20 mA each). Exceeding this current risks VOUT droop below required SRAM VCC minimums and invalidates guaranteed tWPT/tCER timing-designers must verify total SRAM quiescent + active current against the BQ2204ASNTR's 160 mA limit.