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Renesas M51945BJFP#200D
- Part No.:
- M51945BJFP#200D
- Manufacturer:
- Renesas
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
M51945BJFP#200D.pdf
- Description:
- IC SUPERVISOR VOLT DET SYS RESET
- Quantity:
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Inventory:7,700
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Product details
Overview
M51945BJFP#200D from Renesas Electronics is an L-reset-type voltage-detecting system reset IC with open-collector output, designed for monitoring supply rails and asserting active-low reset signals to microcontrollers and logic circuits. It features a 1.25 V internal reference, 15 mV typical hysteresis, 2–17 V supply range, and supports external resistor-based detection voltage setting from 2 V to 15 V. It is used in embedded power-on reset and brown-out detection circuits.
For engineers reviewing the M51945BJFP#200D datasheet, M51945BJFP#200D pinout, M51945BJFP#200D application, or M51945BJFP#200D equivalent, this page delivers verified technical context, exact pin functions, real-world use cases, and validated alternative parts - all grounded in Renesas' REJ03D0774-0300 Rev.3.00 specification.
Technical Context
This IC implements a precision comparator architecture with a stable 1.25 V bandgap reference and 25 µA typical input bias current. Its detection threshold is set externally via resistor dividers on the input pin, enabling flexible voltage monitoring without trimming.
The M51945BJFP#200D operates as an "L reset" device (active-low output) with open-collector output stage, requiring an external pull-up resistor. It delivers 4 µs typical propagation delay and maintains functionality down to 0.55 V supply (at RL = 100 kΩ), supporting low-voltage system initialization.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Detection Voltage | 1.25 V (typical); sets reset assertion threshold via external R1/R2 divider - enables custom supply monitoring from 2 V to 15 V |
| Hysteresis | 15 mV (typical); prevents chatter during slow-rising/falling supply transitions by introducing 1.2% voltage margin |
| Supply Range | 2 V to 17 V; supports wide-input systems including 3.3 V, 5 V, and 12 V rails without external regulation |
| Output Type | Open-collector; allows level-shifting, wired-OR reset buses, and compatibility with diverse logic families (TTL/CMOS) |
| Propagation Delay | 4 µs (tPHL, typ); ensures fast response to supply collapse while avoiding noise-induced false resets |
| Threshold Operating Voltage | 0.55 V (typ, RL = 100 kΩ); guarantees internal circuit operation even during deep brown-out conditions |
| Input Bias Current | 100 nA (typ); minimizes resistor-divider loading error - critical for accurate detection voltage setting |
Pinout & Package
Package: 5-pin SIP (5P5T), plastic single-in-line package, 2.54 mm pitch, 11.9 × 4.0 mm footprint, lead material Cu alloy, Ni/Pd/Au plating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Input) | Voltage sense input | Accepts divided supply voltage; comparator compares against 1.25 V reference - sets detection threshold |
| 2 (GND) | Ground reference | Return path for internal circuitry and output sink current; must be low-impedance for stable reset timing |
| 3 (Power-supply) | VCC supply input | Powers internal comparator and bias circuitry; valid from 2 V to 17 V - independent of sensed voltage rail |
| 4 (Output) | Open-collector reset output | Drives low when supply drops below threshold; requires external pull-up to define logic-high level and drive strength |
| 5 (NC) | No connection | Internally unconnected pin; must remain floating - no routing or soldering required |
Key Features
| Feature | Design Value |
|---|---|
| Externally programmable detection voltage | Enables precise reset thresholds (2–15 V) using two resistors - eliminates need for multiple fixed-threshold ICs |
| Low operating supply voltage | Functions down to 0.55 V supply (RL = 100 kΩ), ensuring reliable reset assertion during deep brown-out events |
| Wide supply voltage range | Operates from 2 V to 17 V - supports direct integration into 3.3 V, 5 V, and 12 V systems without auxiliary regulators |
| Open-collector output | Allows shared reset bus across multiple devices and interface with mixed-voltage logic families (e.g., 3.3 V MCU + 5 V peripheral) |
| 15 mV typical hysteresis | Prevents oscillation during marginal supply conditions - eliminates need for external hysteresis components |
Applications
| Microcontroller Power-On Reset | Battery Voltage Monitoring |
|---|---|
Use Scenario: Ensuring clean startup of an 8-bit MCU after battery insertion or power recovery. IC Role / Device Role / Timing Role: Monitors main 3.3 V supply and asserts active-low /RESET until voltage stabilizes above 3.1 V. Use Value: Prevents code execution from corrupted memory due to insufficient VDD - eliminates need for RC-based reset timers with poor temperature stability. |
Use Scenario: Detecting end-of-life in a 9 V alkaline-powered portable instrument. IC Role / Device Role / Timing Role: Senses battery voltage via resistor divider; triggers low-battery warning at 6.8 V. Use Value: Enables accurate, resistor-programmable threshold without trimming - replaces discrete comparator + reference solutions with higher BOM cost and layout area. |
| DC/DC Converter Supervision | Industrial Logic System Reset |
Use Scenario: Validating output stability of an isolated 5 V DC/DC converter before enabling downstream loads. IC Role / Device Role / Timing Role: Input tied to converter output; asserts /RESET until regulated 5 V reaches 4.75 V with 20 ms delay. Use Value: Provides deterministic, voltage-accurate enable sequencing - avoids reliance on converter's internal soft-start timing which may vary across load/temperature. |
Use Scenario: Coordinating reset across multiple CMOS logic blocks (FPGA, CPLD, bus transceivers) in a PLC backplane. IC Role / Device Role / Timing Role: Generates synchronized active-low reset pulse across distributed logic; open-collector output supports wired-OR bus topology. Use Value: Guarantees simultaneous de-assertion across heterogeneous logic families - eliminates metastability from staggered reset release in multi-rail systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar voltage-detecting reset applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLV803EB29DBZR | Fixed 2.93 V threshold; SOT-23-3 package; 3.5 µs max tPLH; no external resistor programming | Best for space-constrained designs needing simple, fixed-threshold reset without adjustment flexibility | Select when detection voltage is fixed and PCB area is critical - not suitable for custom threshold requirements |
| MAX809SEUR+T | Fixed 3.08 V threshold; SOT-23-3; 250 ms min reset timeout; built-in delay capacitor option | Preferred where guaranteed minimum reset pulse width is required for slow-starting processors | Choose when system demands long-duration reset assertion - M51945BJFP#200D lacks internal timer and relies on external RC for delay |
Compared with TLV803EB29DBZR and MAX809SEUR+T, the M51945BJFP#200D uniquely supports user-defined detection voltages via external resistors, offers wider supply range (2–17 V vs. ≤6 V), and provides lower operating voltage capability (0.55 V vs. ≥0.9 V), making it suitable for legacy industrial and wide-input applications where flexibility outweighs ultra-small packaging.
Availability
M51945BJFP#200D is available at Aetrix Electronics and suitable for microcontroller reset, battery monitoring, DC/DC supervision, and industrial logic system reset requiring stable component supply and long-lifecycle support.
Supply support for M51945BJFP#200D 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
Renesas Electronics Corporation is a global semiconductor leader specializing in microcontrollers, analog, power, and timing solutions for industrial, automotive, and infrastructure markets.
The M51945BJFP#200D belongs to Renesas' legacy voltage-detecting reset IC series, engineered for robust, resistor-programmable supply monitoring in cost-sensitive and wide-input industrial control systems.
FAQ
What is the detection voltage accuracy of the M51945BJFP#200D?
The M51945BJFP#200D has a detection voltage of 1.25 V (typical), with a min/max range of 1.20 V to 1.30 V at 25°C. This ±4% tolerance includes initial accuracy and is further affected by input bias current (100 nA typ) when using high-value external resistors. For best accuracy, keep R1 + R2 ≤ 200 kΩ per the REJ03D0774-0300 design guidelines. The M51945BJFP#200D does not include factory trimming.
Can the M51945BJFP#200D be used with a 3.3 V supply rail?
Yes - the M51945BJFP#200D operates over 2 V to 17 V, making it fully compatible with 3.3 V systems. When monitoring a 3.3 V rail, configure the external resistor divider so that the input pin sees 1.25 V at the desired trip point (e.g., R1 = 33 kΩ, R2 = 20 kΩ yields ~3.3 V detection). The M51945BJFP#200D's open-collector output can be pulled up to 3.3 V or any compatible logic level.
Does the M51945BJFP#200D provide a built-in reset timeout delay?
No - the M51945BJFP#200D is a pure voltage comparator with no internal timer. Reset pulse width depends entirely on supply ramp characteristics and external RC networks. To add delay, place a capacitor between the output and GND (with series resistor if needed), as shown in Figure 1 of REJ03D0774-0300. The M51945BJFP#200D itself asserts reset immediately upon threshold crossing.
What is the maximum sink current rating for the M51945BJFP#200D output?
The M51945BJFP#200D output is rated for 4 mA maximum sink current under normal operation (absolute max = 6 mA). At 4 mA and VCC = 5 V, the saturation voltage is ≤0.4 V (typical 0.2 V), ensuring strong logic-low drive. Exceeding 4 mA risks violating the 300 mW power dissipation limit in the 5P5T package, especially at elevated ambient temperatures.
Is the M51945BJFP#200D pin-compatible with other members of the M51945/M51946 family?
Yes - the M51945BJFP#200D shares identical 5-pin SIP (5P5T) pinout with M51945AFP, M51945BFP, and M51946x variants. Pin 1 = Input, Pin 2 = GND, Pin 3 = VCC, Pin 4 = Output, Pin 5 = NC. However, functional differences exist: M51945x are L-reset (active-low), M51946x are H-reset (active-high), and suffix 'A' denotes built-in load while 'B' denotes open-collector output - the M51945BJFP#200D is L-reset + open-collector.
M51945BJFP#200D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- -
- Number of Voltages Monitored:
- -
- Voltage - Threshold:
- -
- Output:
- -
- Reset:
- -
- Reset Timeout:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
M51945BJFP#200D FAQ
1.How can I place an order for M51945BJFP#200D through Aetrix?
Please submit a Request for Quotation (RFQ) for M51945BJFP#200D on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for M51945BJFP#200D reliable?
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6.How does Aetrix verify that M51945BJFP#200D is sourced from the original manufacturer or authorized distributors?
All M51945BJFP#200D products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that M51945BJFP#200D meets industry standards.
7.What is the process for return or replacement of M51945BJFP#200D?
All M51945BJFP#200D units undergo pre-shipment inspection (PSI). If there is an issue with M51945BJFP#200D, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The M51945BJFP#200D part is unused and in its original packaging.
Return procedure for M51945BJFP#200D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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