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Texas Instruments LM809M3-3.08
- Part No.:
- LM809M3-3.08
- Manufacturer:
- Texas Instruments
- Category:
- Supervisors
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
LM809M3-3.08.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:399
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Product details
Overview
LM809M3-3.08 from Texas Instruments is a 3-pin SOT-23 microprocessor reset supervisor IC with a factory-trimmed 3.08 V ±3% reset threshold, 240 ms typical reset timeout, and active-low open-drain RESET output. It monitors 3.3 V supply rails in embedded controllers and ensures reliable power-up sequencing in industrial automation systems.
For engineers reviewing the LM809M3-3.08 datasheet, LM809M3-3.08 pinout, LM809M3-3.08 application, or LM809M3-3.08 equivalent, key selection criteria include reset threshold accuracy over temperature (±3% at 25°C, ±5% over –40°C to +105°C), guaranteed RESET validity down to VCC ≥1 V, low 15 µA supply current, and immunity to sub-20 µs VCC transients.
Technical Context
The LM809M3-3.08 implements a precision bandgap-based voltage comparator with hysteresis to detect VCC drops below 3.08 V. Its internal timer guarantees a minimum 140 ms (typical 240 ms) active-low reset pulse after VCC recovers above threshold, ensuring microprocessor core and peripheral initialization completes before release.
It operates across –40°C to +105°C with full electrical specification, features 30 ppm/°C threshold temperature coefficient, and maintains valid RESET output even as VCC declines to 1 V-enabling robust brown-out detection in battery-backed and portable equipment.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.08 V ±3% at 25°C; enables precise monitoring of 3.3 V supplies within 90–95% of nominal rail. |
| Reset Timeout | 240 ms typical; ensures sufficient hold time for microcontroller boot ROM execution and PLL lock. |
| Supply Current | 15 µA typical at 25°C; supports >10-year battery life in always-on sensor nodes. |
| VCC Operating Range | 1.0 V to 5.5 V; guarantees functional RESET assertion down to 1 V, critical for graceful shutdown. |
| Output Type | Active-low open-drain RESET; compatible with 1.8 V–5 V logic families via external pull-up. |
| Transient Immunity | Rejects VCC glitches ≤20 µs duration when 100 mV below threshold; reduces false resets in noisy environments. |
| Temp Range | –40°C to +105°C; qualified for industrial control cabinets and automotive under-hood auxiliary modules. |
Pinout & Package
SOT-23 (DBZ) package, 2.92 mm × 1.30 mm body size, 3-pin surface-mount configuration with gull-wing leads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND | Ground reference | Return path for internal comparator and output stage; must connect to system ground plane with low impedance. |
| RESET | Active-low open-drain output | Drives low during reset condition; requires external pull-up resistor to host VCC or logic rail for proper level translation. |
| VCC | Supply input | Monitored power rail input; also powers internal circuitry; accepts 1.0–5.5 V with transient immunity up to 100 V/µs. |
Key Features
| Feature | Design Value |
|---|---|
| Precision 3.08 V threshold | Factory-trimmed to ±3% at 25°C and ±5% over full temperature range, matching 3.3 V supply tolerance bands. |
| Guaranteed 140 ms min reset pulse | Ensures compatibility with slow-starting DC/DC converters and microcontrollers requiring extended reset hold times. |
| Valid RESET down to VCC = 1 V | Prevents undefined processor state during deep brown-out; enables controlled shutdown sequences in battery systems. |
| 15 µA supply current | Minimizes quiescent load on backup batteries or energy-harvesting sources in always-on edge devices. |
| 30 ppm/°C tempco | Maintains tight threshold stability across industrial temperature range, eliminating need for external compensation. |
Applications
| Industrial PLC I/O Module | Smart Energy Meter |
|---|---|
Use Scenario: Power cycling during grid voltage sags or communication interruptions. IC Role / Device Role / Timing Role: Monitors 3.3 V MCU supply and asserts active-low RESET until stable for ≥240 ms post-recovery. Use Value: Prevents corrupted firmware execution or EEPROM writes during marginal supply conditions. |
Use Scenario: Battery-backed real-time clock and metrology ASIC operation during AC mains failure. IC Role / Device Role / Timing Role: Detects 3.3 V rail collapse and holds MCU in reset while switching to backup power source. Use Value: Ensures atomic data logging and prevents partial register updates during power transition. |
| Programmable Logic Controller | Factory Automation Sensor Node |
Use Scenario: Hot-swap insertion of modular I/O cards into live backplane. IC Role / Device Role / Timing Role: Provides localized reset supervision for card-specific MCU, independent of main chassis controller. Use Value: Eliminates cross-talk-induced resets and enables deterministic card initialization sequence. |
Use Scenario: Intermittent solar charging causing repeated VCC ramp-up/ramp-down cycles. IC Role / Device Role / Timing Role: Generates clean, debounced reset pulses on each valid VCC rise above 3.08 V with 240 ms timeout. Use Value: Avoids MCU lockup due to insufficient power-up timing margin during unstable input conditions. |
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 | 3.08 V threshold, same SOT-23-3 package, but 140 ms min reset timeout (vs. 240 ms typical for LM809M3-3.08); higher 20 µA supply current. | Less margin for slow-starting peripherals; may require validation if system relies on ≥200 ms reset hold. | Select when footprint compatibility is critical and shorter timeout is acceptable. |
| TPS3808G30DBVR | 3.0 V threshold (not 3.08 V), adjustable delay option, higher 2.5 µA quiescent current, but requires external capacitor for timing. | Threshold mismatch (3.0 V vs. 3.08 V) risks premature release on 3.3 V rails near lower spec limit; adds BOM and layout complexity. | Choose only if programmable delay or ultra-low IQ outweighs fixed-threshold precision requirement. |
Compared with MAX809TRD3-T and TPS3808G30DBVR, the LM809M3-3.08 delivers tighter threshold accuracy at 3.08 V, longer guaranteed reset hold time, and simpler implementation-making it optimal for cost-sensitive, high-volume industrial controllers where 3.3 V rail integrity is mission-critical.
Availability
LM809M3-3.08 is available at Aetrix Electronics and suitable for industrial PLCs, smart energy meters, factory automation sensors, and programmable logic controllers requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LM809M3-3.08 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 microcontroller solutions.
The LM809 series belongs to TI's microprocessor supervisory IC product line, designed specifically for reliable power-on reset, brown-out protection, and supply monitoring in industrial, automotive, and computing systems.
FAQ
What is the exact reset threshold voltage of LM809M3-3.08 and how does it vary with temperature?
The LM809M3-3.08 has a factory-programmed reset threshold of 3.08 V with ±3% tolerance at 25°C. Over the full operating range (–40°C to +105°C), the threshold varies by ±5%, corresponding to 2.92 V minimum and 3.23 V maximum. Its temperature coefficient is specified at 30 ppm/°C, ensuring predictable drift across thermal gradients in industrial enclosures.
Does LM809M3-3.08 provide a reset signal when VCC falls below 1 V?
No-LM809M3-3.08 guarantees valid RESET output only for VCC ≥1 V. Below 1 V, the internal circuitry cannot sustain output drive capability. For applications requiring reset assertion down to 0 V, a 100 kΩ pull-down resistor on the RESET pin is recommended per TI's design guidance to prevent floating states during deep brown-out.
What is the function of the RESET pin on LM809M3-3.08 and what external components are required?
The RESET pin on LM809M3-3.08 is an active-low open-drain output. It requires an external pull-up resistor to a logic-compatible voltage (e.g., 3.3 V or 5 V) to generate a defined high-level signal when not asserted. TI recommends values between 10 kΩ and 100 kΩ depending on bus capacitance and rise-time requirements.
How does LM809M3-3.08 handle fast transients on the VCC line?
LM809M3-3.08 rejects negative-going VCC transients ≤20 µs in duration when the dip is 100 mV below the 3.08 V threshold. This immunity is achieved through internal filtering and comparator hysteresis. For enhanced noise rejection, TI recommends placing a 0.1 µF ceramic capacitor as close as possible to the VCC pin.
Is LM809M3-3.08 pin-compatible with other members of the LM809 family?
Yes-LM809M3-3.08 shares identical SOT-23 (DBZ) 3-pin packaging and pinout (GND, RESET, VCC) with all LM809 variants (e.g., LM809M3-2.63, LM809M3-4.63). This allows direct substitution within the same footprint when adjusting reset threshold for different supply rails, provided system timing and voltage margin requirements remain satisfied.
LM809M3-3.08 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:
- 3.08V
- 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
LM809M3-3.08 FAQ
1.How can I place an order for LM809M3-3.08 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM809M3-3.08 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 LM809M3-3.08 reliable?
The price and inventory of LM809M3-3.08 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM809M3-3.08 is usually 5 days.
3.What payment methods are accepted for LM809M3-3.08?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM809M3-3.08 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM809M3-3.08?
LM809M3-3.08 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM809M3-3.08 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 LM809M3-3.08?
For technical support, including LM809M3-3.08 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM809M3-3.08 requirements.
6.How does Aetrix verify that LM809M3-3.08 is sourced from the original manufacturer or authorized distributors?
All LM809M3-3.08 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 LM809M3-3.08 meets industry standards.
7.What is the process for return or replacement of LM809M3-3.08?
All LM809M3-3.08 units undergo pre-shipment inspection (PSI). If there is an issue with LM809M3-3.08, 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 LM809M3-3.08 part is unused and in its original packaging.
Return procedure for LM809M3-3.08:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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