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Texas Instruments LM809M3-2.93
- Part No.:
- LM809M3-2.93
- Manufacturer:
- Texas Instruments
- Category:
- Supervisors
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
LM809M3-2.93.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,662
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Product details
Overview
LM809M3-2.93 from Texas Instruments is a 3-pin SOT-23 microprocessor supervisory circuit with a factory-programmed 2.93 V reset threshold, active-low RESET output, 240 ms typical reset timeout, and 15 µA typical supply current. It monitors VCC in brown-out, power-up, and power-down conditions for 3.3 V systems and ensures reliable µP reset assertion.
For engineers reviewing the LM809M3-2.93 datasheet, LM809M3-2.93 pinout, LM809M3-2.93 application, or LM809M3-2.93 equivalent, key selection criteria include precision 2.93 V threshold tolerance (±30 mV at 25°C), guaranteed RESET validity down to VCC ≥1 V, immunity to VCC transients ≤20 µs, and compatibility with bidirectional µP reset pins via 4.7 kΩ series resistor.
Technical Context
The LM809M3-2.93 implements a precision voltage comparator with internal reference to monitor VCC against its 2.93 V threshold. When VCC falls below this value, the active-low RESET output is driven low and remains asserted for a minimum of 140 ms-240 ms typical-after VCC rises above threshold.
Its design includes transient immunity circuitry rejecting negative-going VCC glitches up to 20 µs duration when overdriven by 100 mV below threshold, and supports operation across –40°C to +105°C with ±30 ppm/°C temperature coefficient on the reset threshold.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.93 V ±30 mV at 25°C; tight tolerance ensures reliable detection of 3.3 V supply brown-out at ~89% nominal. |
| Reset Timeout | 240 ms typical; guarantees sufficient hold time for µP initialization before release. |
| Supply Current | 15 µA typical at 25°C; enables use in battery-powered equipment without significant drain. |
| Operating Temp | –40°C to +105°C; qualified for industrial and automotive under-hood environments. |
| VCC Range | 1.0 V to 5.5 V; RESET output remains valid even as supply collapses to 1 V. |
| Output Type | Active-low open-drain RESET; sinks 1.2 mA at 0.3 V drop, compatible with standard CMOS logic inputs. |
| Transient Immunity | Rejects VCC glitches ≤20 µs when 100 mV below threshold; reduces false resets in noisy power rails. |
Pinout & Package
LM809M3-2.93 is housed in a 3-pin SOT-23 (DBZ) package measuring 2.92 mm × 1.30 mm, with gull-wing leads and RoHS-compliant matte tin (SN) finish. Pin 1 is GND, Pin 2 is RESET (active-low output), and Pin 3 is VCC (supply input).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Ground reference | Provides return path for internal comparator and output stage; must be connected to system ground plane for stable threshold reference. |
| RESET (Pin 2) | Active-low reset output | Drives low during fault conditions; requires external pull-up for high-impedance µP interfaces; sinks 1.2 mA at 0.3 V max. |
| VCC (Pin 3) | Supply voltage input | Monitored supply rail; accepts 1.0–5.5 V; internal circuitry remains functional down to 1 V to ensure valid RESET state during collapse. |
Key Features
| Feature | Design Value |
|---|---|
| Precision 2.93 V threshold | Factory-trimmed to ±30 mV at 25°C and ±70 mV over full temperature range, enabling accurate monitoring of 3.3 V supplies. |
| Guaranteed 240 ms reset pulse | Ensures µP reset hold time exceeds boot ROM execution time, preventing premature release and system lockup. |
| Low 15 µA quiescent current | Minimizes battery drain in portable instrumentation and remote sensors where duty cycle is critical. |
| VCC transient rejection | Immune to 20 µs negative spikes at 100 mV below threshold, eliminating need for additional filtering in moderate-noise environments. |
| Valid RESET down to VCC = 1 V | Prevents floating reset line during deep brown-out; maintains defined logic state until supply reaches functional level. |
Applications
| Industrial PLC Control | Smart Energy Metering |
|---|---|
|
Use Scenario: Programmable logic controllers operating in factory-floor environments with fluctuating 3.3 V I/O rails. IC Role / Device Role / Timing Role: Monitors 3.3 V supply and asserts active-low RESET to ARM Cortex-M µP during voltage sags caused by motor switching noise. Use Value: Prevents firmware corruption by ensuring µP remains held in reset until supply stabilizes above 2.93 V with 240 ms margin. |
Use Scenario: Revenue-grade electricity meters with isolated 3.3 V MCU domain powered from flyback converter. IC Role / Device Role / Timing Role: Provides brown-out detection on meter's 3.3 V rail and triggers safe shutdown sequence before EEPROM write corruption occurs. Use Value: 15 µA supply current extends battery backup runtime; ±30 ppm/°C threshold drift ensures accuracy across –25°C to +70°C field deployment. |
| Automotive Body Control Module | Portable Medical Sensor Hub |
|
Use Scenario: BCMs in 12 V vehicle architectures using LDO-regulated 3.3 V domain for CAN interface and lighting control ICs. IC Role / Device Role / Timing Role: Supervises 3.3 V rail during cold-crank events where input drops to 6 V, causing LDO output to sag near 2.93 V. Use Value: 240 ms timeout prevents spurious resets during brief sags; –40°C to +105°C rating matches under-dash thermal requirements. |
Use Scenario: Handheld ECG sensor with coin-cell battery and ultra-low-power 3.3 V MCU subsystem. IC Role / Device Role / Timing Role: Detects battery voltage decay below 2.93 V and holds µP in reset to avoid erratic ADC sampling or BLE transmission errors. Use Value: 15 µA quiescent current adds negligible load; active-low output directly interfaces with µP's dedicated reset pin without level-shifting. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor reset applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX809TRD3-T | 2.93 V threshold, same SOT-23-3 package, but 1.25 µA max supply current vs LM809M3-2.93's 15 µA typical; 200 ms min reset timeout. | Better suited for ultra-low-power battery applications where sub-µA standby matters; less tolerant of VCC transients (no specified immunity spec). | Select MAX809TRD3-T only if <1 µA supply current is mandatory and transient noise is minimal. |
| TPS3808G33DBVR | Adjustable threshold (0.4–5 V) via external resistor divider; 350 ms fixed timeout; 1.1 µA typical supply current; same SOT-23-6 footprint (not pin-compatible). | Enables flexible voltage monitoring across multiple rails; requires PCB redesign due to 6-pin layout and different pinout. | Choose TPS3808G33DBVR only when multi-threshold flexibility justifies layout change and added BOM complexity. |
Compared with MAX809TRD3-T and TPS3808G33DBVR, LM809M3-2.93 offers optimal balance of precision 2.93 V detection, proven transient immunity, and direct SOT-23-3 drop-in replacement capability for legacy 3.3 V µP designs without layout modification.
Availability
LM809M3-2.93 is available at Aetrix Electronics and suitable for industrial PLC control, smart energy metering, automotive body control modules, and portable medical sensor hubs requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LM809M3-2.93 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 founded in 1930, specializing in analog and embedded processing technologies with broad industrial, automotive, and consumer applications.
The LM809 series was designed specifically as a cost-optimized, precision voltage supervisor for microprocessor reset in space-constrained, thermally demanding embedded systems-emphasizing reliability, low power, and ease of integration.
FAQ
What is the exact reset threshold voltage of LM809M3-2.93 and how does it vary with temperature?
The LM809M3-2.93 has a factory-programmed nominal reset threshold of 2.93 V, with tolerance of ±30 mV at 25°C. Over the full operating range (–40°C to +105°C), threshold variation is limited to ±70 mV, corresponding to a temperature coefficient of ±30 ppm/°C. This ensures consistent brown-out detection for 3.3 V systems across industrial environments without calibration.
Does LM809M3-2.93 provide a valid reset signal when VCC drops below 1 V?
No-LM809M3-2.93 guarantees RESET output validity only down to VCC ≥1 V. Below 1 V, the internal circuitry cannot maintain defined logic states, and RESET may float. For continuous validity to ground, TI recommends adding a 100 kΩ pull-down resistor from RESET to GND, as documented in the LM809 datasheet Figure 7.
What is the minimum and typical reset timeout duration for LM809M3-2.93?
LM809M3-2.93 provides a minimum reset active timeout of 140 ms and a typical value of 240 ms after VCC rises above the 2.93 V threshold. This timeout is fully specified over temperature and ensures sufficient hold time for microprocessor initialization sequences, including flash memory access and peripheral configuration.
Can LM809M3-2.93 interface directly with a microprocessor that has a bidirectional reset pin?
Yes-LM809M3-2.93 can interface with bidirectional µP reset pins (e.g., Motorola 68HC11) using a 4.7 kΩ series resistor between RESET and the µP pin, as shown in Figure 9 of the datasheet. This prevents contention when the µP drives the line high while LM809M3-2.93 asserts low, ensuring clean reset assertion without latch-up risk.
What package type and lead finish does LM809M3-2.93 use, and is it RoHS compliant?
LM809M3-2.93 uses the SOT-23 (DBZ) package with 3 gull-wing leads, 2.92 mm × 1.30 mm body size, and matte tin (SN) lead finish. It is RoHS compliant (lead-free), rated MSL Level-1 at 260°C peak reflow, and supplied in 1000-piece tape-and-reel format with Q3 pin-1 orientation.
LM809M3-2.93 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 2.93V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 105°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
LM809M3-2.93 FAQ
1.How can I place an order for LM809M3-2.93 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM809M3-2.93 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 LM809M3-2.93 reliable?
The price and inventory of LM809M3-2.93 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM809M3-2.93 is usually 5 days.
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Once your LM809M3-2.93 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LM809M3-2.93?
For technical support, including LM809M3-2.93 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM809M3-2.93 requirements.
6.How does Aetrix verify that LM809M3-2.93 is sourced from the original manufacturer or authorized distributors?
All LM809M3-2.93 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 LM809M3-2.93 meets industry standards.
7.What is the process for return or replacement of LM809M3-2.93?
All LM809M3-2.93 units undergo pre-shipment inspection (PSI). If there is an issue with LM809M3-2.93, 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 LM809M3-2.93 part is unused and in its original packaging.
Return procedure for LM809M3-2.93:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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