BQ2201PN

Overview

The bq2201PN is an SRAM Nonvolatile Controller Unit manufactured by Texas Instruments in an 8-pin narrow plastic DIP package. It provides power monitoring and switching for 3-volt battery-backup applications, converting standard CMOS SRAM into nonvolatile read/write memory. The device features a precision comparator that monitors the 5V VCC input for out-of-tolerance conditions to force write-protect control. It supports 5% or 10% supply operation via the THS pin, with typical power-fail detection thresholds of 4.62V and 4.37V respectively. The chip-enable propagation delay is less than 10ns.

Feature Summary

• Provides hardware-based conversion of standard CMOS SRAM into nonvolatile read/write memory through automatic power monitoring and switching.
• Features a precision comparator that detects out-of-tolerance supply conditions to unconditionally write-protect external SRAM during power failures.
• Supports dual 3-volt primary backup cell inputs with internal isolation switches to manage energy sources and prevent battery drain.

Applications

• Battery-backed static RAM systems requiring nonvolatile data retention
• Power monitoring and switching circuits for 3-volt battery-backup applications
• Write-protect control logic for standard CMOS SRAM modules

Procurement Notes

Verify the specific ordering suffix against the manufacturer's current documentation to confirm the temperature range and package type. The 'PN' designation indicates an 8-pin narrow plastic DIP package. Ensure the selected variant matches the required operating temperature range, as commercial and industrial options are available within the bq2201 family. Cross-reference the latest datasheet revision to confirm active status and any potential design changes.

Selection Notes

Select this component when designing systems that require hardware-level nonvolatility for standard CMOS SRAM without complex software management. The bq2201PN is suitable for applications needing fast chip-enable propagation delays under 10ns and precise power-fail detection thresholds. Consider the 8-pin DIP package constraints and the requirement for external 3-volt primary cells for the BC1 and BC2 inputs when finalizing the circuit design.

Part Context

The bq2201 belongs to the bq series of power management and battery protection devices from Texas Instruments. This specific model focuses on SRAM nonvolatility rather than direct battery charging or fuel gauging. It serves as a bridge between standard volatile memory components and reliable long-term data storage solutions in embedded systems.

Replacement Considerations

Check for other variants within the bq2201 family, such as the SN (SOIC) or S (16-pin SOIC) packages, if footprint compatibility allows. Verify if the industrial temperature grade (N suffix) is required instead of the commercial grade provided by the PN package.

FAQ

How is the power-fail detection threshold configured?

The threshold is set by the THS pin. Tying THS to VSS configures the device for 5% supply operation with a typical detection at 4.62V, while tying it to VCC sets it for 10% operation at 4.37V.

What is the function of the BC1 and BC2 pins?

BC1 and BC2 are inputs for two 3-volt primary backup cells. The device automatically switches the VOUT output from BC1 to BC2 if the voltage at BC1 falls below 2.5V.