The R3111N122A-TR-FE from Nisshinbo Micro Devices Inc. is a single-channel voltage supervisor IC designed to monitor system supply rails and generate reset signals when voltage drops below a defined threshold. This device implements a 1.2V detection threshold with active-low output, suitable for microcontroller reset management, power sequencing control, and supply fault detection in embedded systems.
Built around an open-drain output architecture, the R3111N122A-TR-FE allows direct connection to pull-up networks and enables wired-OR configurations with other supervisory circuits. The active-low reset output asserts when the monitored voltage falls below 1.2V and maintains assertion until the supply recovers and stabilizes, with a maximum reset timeout delay of 100µs. This brief release time supports rapid system restart after transient faults while filtering supply noise that could trigger false resets.
The device operates across the industrial temperature range of -40°C to 85°C, maintaining threshold accuracy and output timing across thermal extremes common in automotive modules, industrial controllers, and outdoor equipment. Power consumption remains minimal throughout operation, making it compatible with battery-powered designs and low-power standby modes where supply current budgets are tightly constrained.
Housed in a compact SOT-23-3 surface-mount package, the R3111N122A-TR-FE occupies minimal board area and simplifies routing in dense PCB layouts. The three-pin configuration supports straightforward implementation with VDD, ground, and reset output connections. Tape and reel packaging enables automated pick-and-place assembly for volume production, and MSL-1 moisture sensitivity rating eliminates floor-life restrictions and baking requirements prior to reflow soldering.
As part of the R3111x series, the device is manufactured to RoHS3 compliance standards and carries REACH unaffected status. The active product status indicates ongoing production support, and availability of 4365 pieces in new original stock supports both prototype development and production fulfillment. This voltage detector serves designs requiring reliable supply monitoring with minimal external components, particularly in cost-sensitive applications where discrete comparator implementations would increase BOM count and board complexity.
R3111N122A-TR-FE (1)
Selecting a Compatible Replacement for Nisshinbo R3111N122A-TR-FE Voltage Detector
Finding an equivalent or alternative part for the Nisshinbo Micro Devices Inc. R3111N122A-TR-FE is not only a matter of matching a 1.2 V threshold. This device is a single-channel voltage detector in a SOT-23-3 package with an open-drain or open-collector active-low output and a short reset timeout. Replacement evaluation must consider threshold accuracy, output topology, reset timing, package pin compatibility, operating current, temperature range, and how the reset signal is used in the surrounding circuit.
Potential replacement and alternative part numbers for R3111N122A-TR-FE include:
- Torex XC61CN1202MR-G
- ABLIC S-80812CNY-B2-U
- ROHM BD48K12G-TL
- Texas Instruments TPS3839G12DBZR
- Microchip MCP101T-120E/TT
- Diodes Incorporated APX803L-12SA-7
Some of these options are closer electrical substitutes, while others may require layout, timing, or firmware review before use. The best replacement depends on whether the design requires a fast voltage-detect response, a longer reset hold time, direct SOT-23-3 drop-in compatibility, or broader supply-supervision behavior.
Understanding the Nisshinbo R3111N122A-TR-FE Before Choosing an Equivalent Part
The R3111N122A-TR-FE from Nisshinbo Micro Devices Inc. is a PMIC voltage detector from the R3111x series. It monitors one supply voltage and asserts an active-low reset output when the monitored voltage falls below the detection threshold.
| Parameter | R3111N122A-TR-FE Characteristics | Replacement Impact |
|---|---|---|
| Manufacturer | Nisshinbo Micro Devices Inc. | Same-manufacturer replacements may reduce qualification effort, but alternatives from Torex, ABLIC, ROHM, TI, Microchip, and Diodes can be suitable if key parameters match. |
| Function | Single-channel voltage detector / supervisor | Candidate parts must monitor one rail and generate a reset or detect output suitable for the target logic circuit. |
| Threshold Voltage | 1.2 V | The alternative should use a 1.2 V nominal threshold or a threshold acceptable for the processor, FPGA, ASIC, sensor, or low-voltage rail being supervised. |
| Output Type | Open drain or open collector | This allows pull-up flexibility. Push-pull alternatives are not direct substitutes unless the pull-up network and logic interface are redesigned. |
| Reset Polarity | Active low | Replacement parts should provide active-low reset behavior to avoid firmware or logic inversion changes. |
| Reset Timeout | 100 µs maximum | Parts with long reset delays may change power-up sequencing behavior. |
| Package | SOT-23-3 / TO-236-3 / SC-59 | Mechanical and pinout compatibility must be checked, even when the package name appears similar. |
| Mounting | Surface mount | Suitable for compact PCB designs and automated assembly. |
| Operating Temperature | -40°C to +85°C | Alternatives should match or exceed this range for industrial or embedded applications. |
| Compliance | RoHS3 compliant, REACH unaffected, MSL 1 | Useful for production continuity and global regulatory requirements. |
The open-drain output is one of the most influential replacement factors. It lets the reset line be pulled up to a voltage different from the monitored rail, which is common in mixed-voltage systems. A replacement with a push-pull output may electrically conflict with an existing pull-up or shared reset line.
The short reset timeout also affects suitability. R3111N122A-TR-FE behaves more like a fast voltage detector than a supervisor with a long reset delay. If the downstream IC only needs brownout indication, fast detection may be preferred. If the system requires reset to remain asserted after the supply stabilizes, alternatives with built-in reset delay may be acceptable or even beneficial.
Typical applications include low-voltage microcontroller reset circuits, battery-powered equipment, portable electronics, sensor modules, power-rail monitoring, FPGA or ASIC supply supervision, and embedded systems where a 1.2 V rail must be monitored. In each case, the replacement decision should be based on how the reset output interacts with sequencing, startup timing, and fault recovery.
Evaluating R3111N122A-TR-FE Alternative Voltage Detector and Supervisor Parts
| Part Number | Manufacturer | Key Specifications | Product Features | Typical Applications | Why It Can Replace R3111N122A-TR-FE | Main Differences or Limitations | Recommended Usage |
|---|---|---|---|---|---|---|---|
| Torex XC61CN1202MR-G | Torex Semiconductor | 1.2 V voltage detector, N-channel open-drain output, active-low detection, SOT-23 package, low supply current | CMOS voltage detector, compact package, open-drain output suitable for external pull-up | Battery-powered systems, microcontroller reset, portable electronics, low-voltage rail monitoring | It closely matches the original function: 1.2 V detection, open-drain output, small SOT-23 footprint, and low-power operation | Reset delay and pinout must be checked against the R3111N122A-TR-FE layout; detection accuracy may differ by grade | Strong candidate when a fast, simple 1.2 V open-drain voltage detector is required |
| ABLIC S-80812CNY-B2-U | ABLIC Inc. | 1.2 V detector, N-channel open-drain output option, active-low reset/detect output, SOT-23-3 style package | Low-current CMOS voltage detector, stable detection behavior, compact mounting | Embedded controllers, handheld equipment, battery-operated products, brownout detection | Functional behavior is similar to the Nisshinbo R3111N122A-TR-FE for single-rail 1.2 V monitoring with open-drain reset | Ordering-code suffix should be verified for exact output type, package, and threshold tolerance; timing may not be identical | Suitable when low current and SOT-23-3 voltage detection are the main requirements |
| ROHM BD48K12G-TL | ROHM Semiconductor | 1.2 V voltage detector, open-drain reset output family, active-low output, small surface-mount package | Detector IC with stable threshold options and ROHM power-management qualification | Consumer electronics, industrial control boards, logic supply monitoring, reset generation | It provides equivalent 1.2 V undervoltage detection with open-drain style reset behavior | Package is commonly smaller multi-pin style rather than a direct SOT-23-3 match; PCB redesign may be needed | Good alternative when a board revision is possible and ROHM sourcing is preferred |
| Texas Instruments TPS3839G12DBZR | Texas Instruments | Low-power supervisor, approximately 1.2 V class threshold option, open-drain active-low RESET, SOT-23 package family | Nano-power operation, reset supervision behavior, strong documentation and broad distribution | Battery-powered IoT devices, microcontrollers, always-on rails, low-power embedded systems | It can replace the monitoring function when an active-low open-drain reset is needed for a low-voltage rail | Reset delay and exact threshold variant must be reviewed; not always a timing-equivalent substitute for the fast R3111N122A-TR-FE | Recommended where ultra-low current and supplier availability are more valuable than exact reset timeout matching |
| Microchip MCP101T-120E/TT | Microchip Technology | 1.2 V voltage supervisor, active-low open-drain reset, SOT-23-3 package option, extended temperature option depending on suffix | Microcontroller reset supervisor with defined reset behavior and open-drain output | MCU reset circuits, power-on reset, embedded modules, appliance control electronics | It matches the 1.2 V supervision requirement and provides an active-low open-drain reset in a compact package | Reset timeout is typically much longer than the R3111N122A-TR-FE; may alter startup sequencing | Suitable when a delayed reset release is acceptable or desired |
| Diodes Incorporated APX803L-12SA-7 | Diodes Incorporated | 1.2 V supervisor option, active-low reset, SOT-23-3 package family, low supply current | Cost-effective voltage supervisor, small footprint, common reset IC architecture | Consumer products, embedded control, peripheral reset, power-fail monitoring | It can provide the same general 1.2 V reset-supervision role in a SOT-23-3 style package | Output structure, delay time, and pinout must be verified for the selected suffix; delay may differ from the original detector | Practical option for cost-sensitive designs after timing and layout confirmation |
The Torex XC61CN1202MR-G and ABLIC S-80812CNY-B2-U are typically the closest functional alternatives because they are voltage detector ICs rather than reset supervisors with long reset extensions. They are better suited where the R3111N122A-TR-FE is used as a fast undervoltage detector.
The Microchip MCP101T-120E/TT and Diodes Incorporated APX803L-12SA-7 are stronger candidates when the circuit benefits from reset hold time after the monitored rail rises above threshold. However, if the original design depends on the R3111N122A-TR-FE maximum 100 µs timeout, these parts may require timing validation.
The Texas Instruments TPS3839G12DBZR is attractive in low-power systems, but the exact threshold option and reset timing should be checked against the rail tolerance and system startup requirements. The ROHM BD48K12G-TL may be electrically suitable but is less likely to be a direct PCB drop-in where the original SOT-23-3 footprint must remain unchanged.
Comparing R3111N122A-TR-FE Replacement Options for Engineering Trade-Offs
| Evaluation Factor | Torex XC61CN1202MR-G | ABLIC S-80812CNY-B2-U | ROHM BD48K12G-TL | Texas Instruments TPS3839G12DBZR | Microchip MCP101T-120E/TT | Diodes Incorporated APX803L-12SA-7 |
|---|---|---|---|---|---|---|
| Electrical Compatibility | Close match for 1.2 V open-drain voltage detection | Close match if correct N-channel open-drain suffix is selected | Suitable 1.2 V detection, but verify output configuration | Suitable for low-voltage reset supervision; verify exact threshold version | Compatible for 1.2 V active-low open-drain reset | Compatible for 1.2 V reset supervision if suffix matches requirements |
| Mechanical Compatibility | Often suitable for SOT-23 layouts, but pinout must be checked | SOT-23-3 style compatibility possible; pin assignment must be confirmed | May require PCB changes depending on package | SOT-23 package family, but pinout differs by device | SOT-23-3 option supports compact replacement evaluation | SOT-23-3 family option, pinout verification required |
| Reset Timing Behavior | More suitable for fast detect-style applications | Generally closer to detector behavior than delayed supervisors | Timing depends on BD48 variant; confirm delay behavior | May include reset delay behavior different from original | Usually longer reset timeout than R3111N122A-TR-FE | Often longer reset timeout than original detector |
| Performance Difference | Low-current CMOS detector with simple reset behavior | Low-current detector with stable threshold options | Strong voltage detector family, but package and timing may differ | Nano-power advantage for always-on rails | Defined reset hold improves startup robustness | Economical reset supervision, but timing may change operation |
| Reliability and Qualification | Good for portable and embedded designs | Good for low-power industrial and consumer designs | Established PMIC supplier, suitable for board-level redesign | Broadly documented and widely supported | Common MCU reset supervisor family | Widely used in cost-sensitive electronics |
| Package Availability | Compact SOT-23 device | Compact SOT-23-3 style device | Small SMD package, not always direct SOT-23-3 equivalent | SOT-23 package family | SOT-23-3 package option | SOT-23-3 package family |
| Cost Consideration | Typically competitive for detector replacement | Competitive for low-power voltage detection | May be favorable in ROHM-qualified supply chains | May cost more but offers strong sourcing support | Often cost-effective for MCU reset use | Often attractive for volume production |
| Best Fit Scenario | Fast 1.2 V open-drain voltage detection with minimal behavior change | Low-power 1.2 V detector replacement where suffix verification is acceptable | Redesigns where ROHM sourcing or package change is acceptable | Ultra-low-power systems and designs requiring TI ecosystem support | MCU reset circuits needing delayed reset release | Cost-sensitive designs where reset delay is acceptable |
| Main Advantage | Closest detector-style substitute | Strong functional similarity to original detector | Good supplier alternative for voltage detection | Low operating current and broad documentation | Simple SOT-23-3 reset supervisor option | Cost and availability advantages |
| Main Limitation | Confirm pinout and tolerance before drop-in use | Exact ordering code must be validated | Mechanical mismatch risk | Timing may not match fast detector behavior | Reset delay may be too long for detector-only circuits | Output and timing suffix details must be confirmed |
For a direct R3111N122A-TR-FE replacement, the first screening step should be output type. Any substitute should provide an open-drain or open-collector active-low output unless the reset network is redesigned. This is especially relevant if several ICs share the reset line or if the pull-up voltage differs from the monitored 1.2 V rail.
The second screening step is reset timing. Torex XC61CN1202MR-G and ABLIC S-80812CNY-B2-U are generally better suited when the circuit expects quick undervoltage detection similar to the Nisshinbo R3111N122A-TR-FE. Microchip MCP101T-120E/TT and Diodes Incorporated APX803L-12SA-7 are better choices when a power-on reset delay is acceptable. Texas Instruments TPS3839G12DBZR may be preferred where low current consumption and documentation support are deciding factors.
Mechanical compatibility should not be assumed from the SOT-23-3 description alone. Pin order can vary between voltage detector families. Before approving any R3111N122A-TR-FE equivalent part, the PCB footprint, pin mapping, pull-up resistor connection, monitored supply node, ground reference, and reset routing should be checked against the selected datasheet.
For procurement and design validation, obtain current quotations, availability, and ordering-code confirmation for R3111N122A-TR-FE replacement parts through IC-Components.com or by emailing Info@IC-Components.com.
