Texas Instruments BQ2201SNTR

Overview

BQ2201SNTR from Texas Instruments is a CMOS SRAM nonvolatile controller unit that converts standard CMOS SRAM into battery-backed nonvolatile memory. It provides power-fail detection at 4.62 V (5% mode) or 4.37 V (10% mode), conditioned chip-enable output with <10 ns propagation delay, and automatic switching between two 3-V primary backup cells (BC1/BC2) during power loss - used in industrial instrumentation data loggers requiring persistent RAM retention.

For engineers reviewing the BQ2201SNTR datasheet, BQ2201SNTR pinout, BQ2201SNTR application, or BQ2201SNTR equivalent, this device supports precise VCC monitoring, hardware-based write-protection timing control (tWPT = 100 µs typ), dual-cell backup selection, and industrial-temperature operation (-40°C to +85°C) in an 8-pin SOIC package.

Technical Context

The BQ2201SNTR implements a precision comparator for VCC monitoring with threshold selection via THS pin, enabling configurable power-fail detection at either 4.62 V (THS = VSS) or 4.37 V (THS = VCC). Its CECON output is conditionally gated to enforce unconditional SRAM write-protection during voltage droop, independent of CE input state.

An internal analog switch routes VOUT to BC1 (if ≥2.5 V) or BC2 (if BC1 falls below 2.5 V), while isolation logic prevents battery drain unless CE meets strict timing criteria (700 ns low window at 0.48–0.52×VCC between VPFD and VSO). Power-up recovery enforces 120 ms max tCER write-protection hold time.

Key Specifications

Pinout & Package

Package: 8-pin narrow SOIC (SN), RoHS-compliant, MSL Level-1, industrial temperature range (-40°C to +85°C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX690TSA+ and DS1230Y-120, the BQ2201SNTR uniquely delivers sub-10 ns CE propagation, dual 3-V cell arbitration, and user-selectable power-fail thresholds - critical for high-reliability industrial SRAM backup where timing precision and battery longevity are co-optimized.

Availability

BQ2201SNTR is available at Aetrix Electronics and suitable for industrial data loggers, medical device memory backup, programmable logic controllers, and point-of-sale terminals requiring stable component supply across extended product lifecycles.

Supply support for BQ2201SNTR 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 specializing in analog and embedded processing technologies, with leadership in power management, signal chain, and microcontrollers.

The BQ2201SNTR belongs to TI's legacy nonvolatile memory controller product line, designed specifically for hardware-based SRAM backup in mission-critical industrial and medical systems where firmware-independent reliability is mandatory.

FAQ

What is the primary function of the BQ2201SNTR in a memory system?

The BQ2201SNTR serves as a hardware-based SRAM nonvolatile controller that automatically switches external CMOS SRAM to backup power and enforces write-protection during main supply failure. It eliminates software dependency for data retention by using analog comparators and internal switching logic - ensuring the BQ2201SNTR maintains memory integrity even if the host processor crashes or resets during power loss.

How does the BQ2201SNTR determine which backup cell (BC1 or BC2) to use?

The BQ2201SNTR continuously monitors BC1 voltage and uses it as the primary backup source as long as BC1 remains above 2.5 V. If BC1 drops below that threshold, the BQ2201SNTR autonomously engages an internal isolation switch to route VOUT from BC1 to BC2. This behavior is fully analog and requires no configuration or digital control - a core design feature of the BQ2201SNTR.

What is the significance of the THS pin on the BQ2201SNTR?

The THS pin on the BQ2201SNTR selects the power-fail detection threshold: tying THS to VSS configures VPFD at 4.62 V (5% supply tolerance), while tying THS to VCC sets VPFD at 4.37 V (10% tolerance). This allows system designers to align the BQ2201SNTR's failover point precisely with their regulated 5-V rail's specification - a key differentiator versus fixed-threshold alternatives.

Does the BQ2201SNTR require external components to operate?

The BQ2201SNTR operates autonomously with no external passive components required for basic functionality. Only the external SRAM, two 3-V primary cells (BC1/BC2), and proper VCC/VSS connections are needed. The BQ2201SNTR integrates all comparators, switches, and timing logic internally - simplifying layout and eliminating calibration or trimming components typically found in discrete backup solutions.

Is the BQ2201SNTR compatible with modern high-speed SRAMs?

Yes - the BQ2201SNTR supports high-speed SRAM interfacing via its <10 ns chip-enable propagation delay (tCED), which preserves tight access timing budgets. Its CECON output drives standard TTL/CMOS SRAM /CE inputs directly, and its VOUT can supply up to 160 mA to sustain typical 32K×8 or 64K×8 SRAMs during backup - making the BQ2201SNTR suitable for performance-critical applications where latency and current delivery are essential.