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Texas Instruments LM385BDE4-2-5
- Part No.:
- LM385BDE4-2-5
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM385BDE4-2-5.pdf
- Description:
- IC VREF SHUNT 1.5% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,052
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Product details
Overview
LM385BDE4-2-5 from Texas Instruments is a micropower, two-terminal band-gap voltage reference delivering a precise 2.5 V output with ±0.75% initial tolerance (2.462 V to 2.538 V), 1.5 Ω max reference impedance over full temperature range, and operation from 20 μA to 20 mA cathode current. It serves as a stable shunt reference in portable metering, battery-powered instrumentation, and current-loop systems where low power and capacitive-load tolerance are critical.
For engineers reviewing the LM385BDE4-2-5 datasheet, LM385BDE4-2-5 pinout, LM385BDE4-2-5 application, or LM385BDE4-2-5 equivalent, key selection criteria include its 0°C to 70°C operating range, SOIC-8 package, 20 μA minimum cathode current requirement, and 20 ppm/°C max temperature coefficient - all essential for low-power analog reference design and long-term stability validation.
Technical Context
The LM385BDE4-2-5 implements a floating shunt architecture using a band-gap core with high-gain amplifier and internal frequency compensation, enabling stable regulation across all capacitive loads without external components. Its two-terminal configuration (anode and cathode) supports both positive and negative regulation topologies.
Regulation requires sourcing ≥20 μA into the cathode terminal to power the internal voltage divider and amplifier; below this threshold, reference voltage collapses. The device exhibits 120 µV broadband noise (10 Hz–10 kHz) and ±20 ppm/khr long-term drift at 100 µA, confirming suitability for precision, low-drift applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.5 V nominal, 2.462–2.538 V (±0.75%) at 25°C - defines absolute accuracy baseline for calibration-critical circuits |
| Initial Tolerance | ±0.75% - tighter than standard LM385-2.5 (±3%), enabling higher-accuracy system-level references |
| Tempco | ±20 ppm/°C over 0°C to 70°C - ensures <±1.5 mV total drift across full operating range |
| Operating Current | 20 μA to 20 mA cathode current - supports ultra-low-power (e.g., coin-cell) and higher-current (e.g., sensor bias) use cases |
| Reference Impedance | ≤1.5 Ω over full temperature range - minimizes load-induced voltage error in dynamic current-sink applications |
| Noise (10 Hz–10 kHz) | 120 µV RMS - low enough for 12-bit+ ADC reference without additional filtering |
| Long-Term Drift | ±20 ppm/khr at 100 µA - predicts <±200 ppm (0.005 V) drift over 10,000 hours of continuous operation |
Pinout & Package
LM385BDE4-2-5 is housed in an 8-pin SOIC (D) package (4.90 mm × 3.90 mm, 1.75 mm max height), with only pins 1 (ANODE) and 2 (CATHODE) functional; all other pins (3–8) are no-connect (NC).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ANODE (Pin 1) | Common reference node | Typically connected to ground or system return; forms the reference potential for cathode voltage |
| CATHODE (Pin 2) | Shunt current/voltage input | Current must be sourced into this pin to establish 2.5 V across ANODE–CATHODE; regulates by sinking excess current |
| Pins 3–8 | No internal connection | Electrically isolated; no routing or termination required on PCB |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive-load tolerance | Stable with any value of cathode bypass capacitor due to internal frequency compensation - eliminates need for external stabilization networks |
| Micropower operation | 20 μA minimum cathode current enables >10-year battery life in coin-cell-powered meters and sensors |
| Band-gap core architecture | Delivers low-noise (120 µV), low-drift (±20 ppm/khr), and excellent long-term stability - suitable for calibration-grade references |
| Wide current range | 20 μA–20 mA operation allows reuse across low-power sensing and higher-current regulator feedback paths |
| Two-terminal simplicity | Eliminates separate supply rail or enable logic - reduces BOM count and layout complexity in space-constrained designs |
Applications
| Portable Meter References | Current-Loop Instrumentation |
|---|---|
Use Scenario: Handheld multimeters and panel-mounted digital voltmeters requiring stable, battery-operated reference voltage. IC Role / Device Role / Timing Role: Shunt voltage reference establishing 2.5 V reference for ADC input scaling and DAC output calibration. Use Value: ±0.75% initial tolerance and ±20 ppm/°C tempco ensure measurement accuracy remains within Class II specifications across temperature and battery discharge. |
Use Scenario: 4–20 mA industrial transmitters where sensor signal conditioning depends on a stable excitation reference. IC Role / Device Role / Timing Role: Precision shunt reference setting bias current for op-amp-based current sources and sensor bridges. Use Value: ≤1.5 Ω reference impedance prevents gain error drift under varying loop load conditions; 20 μA min current enables ultra-low standby power. |
| Battery-Operated Systems | Thermocouple Cold-Junction Compensation |
Use Scenario: Wireless sensor nodes and IoT edge devices powered by primary lithium or alkaline cells. IC Role / Device Role / Timing Role: Low-power voltage reference for microcontroller ADCs, voltage supervisors, and analog front-end biasing. Use Value: 20 μA operating current extends shelf-life-limited battery runtime; floating shunt topology supports single-supply or split-rail configurations. |
Use Scenario: Precision temperature measurement systems using Type K thermocouples requiring accurate cold-junction compensation. IC Role / Device Role / Timing Role: Stable 2.5 V reference driving temperature-sensing resistors in ratiometric bridge configurations. Use Value: ±20 ppm/khr long-term drift ensures cold-junction accuracy remains within ±0.1°C over multi-year deployments without recalibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM385BLP-2-5 | Same electrical specs, TO-92 (3-pin) package with ANODE/CATHODE/NC pinout; 0°C to 70°C range | Through-hole mounting; lower thermal resistance (157°C/W vs. 112°C/W) but larger footprint | Select for manual assembly, prototyping, or legacy through-hole designs where SOIC reflow is unavailable |
| LM385BPWR-2-5 | Same electrical specs, TSSOP-8 package (3.00 mm × 4.40 mm); RoHS-compliant, moisture-sensitive level 1 | Smaller footprint than SOIC; compatible with fine-pitch automated assembly but requires stricter reflow control | Select for space-constrained PCBs and high-volume SMT production where board area is premium |
Compared with LM385BDE4-2-5, the LM385BLP-2-5 offers identical performance in a through-hole package ideal for prototyping, while the LM385BPWR-2-5 delivers the same precision in a 30% smaller TSSOP footprint - choice depends strictly on mechanical integration requirements, not electrical capability.
Availability
LM385BDE4-2-5 is available at Aetrix Electronics and suitable for portable test instruments, battery-operated systems, and current-loop instrumentation requiring stable component supply with traceable sourcing and lifecycle continuity.
Supply support for LM385BDE4-2-5 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 leader specializing in analog, embedded processing, and connectivity technologies, with decades of expertise in precision analog ICs and voltage references.
The LM385B series belongs to TI's micropower voltage reference product line, engineered specifically for battery-powered instrumentation, portable meters, and low-drift analog signal chains demanding ultra-low quiescent current and high long-term stability.
FAQ
What is the operating temperature range for LM385BDE4-2-5?
The LM385BDE4-2-5 is specified for operation from 0°C to 70°C ambient temperature. This range is narrower than the LM285-2.5 (–40°C to 85°C) but matches the LM385-2.5 and LM385B-2.5 family's commercial-grade specification. Performance parameters including reference voltage, tempco, and impedance are guaranteed only within this interval.
What is the minimum cathode current required for regulation in LM385BDE4-2-5?
The LM385BDE4-2-5 requires a minimum cathode current (IZ(MIN)) of 20 μA to maintain regulation at 2.5 V. Below this threshold, the internal amplifier cannot sustain proper bias, causing reference voltage collapse. This value is confirmed in the Electrical Characteristics table under Recommended Operating Conditions.
Is LM385BDE4-2-5 pin-compatible with other LM385 variants in SOIC-8 packages?
Yes - LM385BDE4-2-5 shares identical SOIC-8 pinout (ANODE on Pin 1, CATHODE on Pin 2, NC on Pins 3–8) with LM385D-2-5, LM385DRG4-2-5, and LM385BD-2-5. However, electrical differences exist: LM385BDE4-2-5 has ±0.75% initial tolerance versus ±3% for standard LM385-2.5, and guaranteed 0°C to 70°C operation.
Does LM385BDE4-2-5 require an external capacitor for stability?
No - the LM385BDE4-2-5 features internal frequency compensation optimized for unconditional stability with any capacitive load on the cathode node. A 0.1-μF ceramic bypass capacitor is optional per layout guidelines but not required for regulation integrity, simplifying design and reducing BOM count.
What is the reference impedance specification for LM385BDE4-2-5 at 25°C?
The LM385BDE4-2-5 has a reference impedance of ≤1.0 Ω (typical 0.4–1.0 Ω) at 100 µA cathode current and 25°C, with a maximum of 1.5 Ω across the full 0°C to 70°C temperature range. This low impedance ensures minimal voltage shift under dynamic load conditions, critical for precision current-source and ADC reference applications.
LM385BDE4-2-5 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Reference Type:
- Shunt
- Output Type:
- Fixed
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- -
- Current - Output:
- 20 mA
- Tolerance:
- ±1.5%
- Temperature Coefficient:
- 20ppm/°C Typical
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- 120µVrms
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 20 µA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LM385BDE4-2-5 FAQ
1.How can I place an order for LM385BDE4-2-5 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385BDE4-2-5 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 LM385BDE4-2-5 reliable?
The price and inventory of LM385BDE4-2-5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM385BDE4-2-5 is usually 5 days.
3.What payment methods are accepted for LM385BDE4-2-5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385BDE4-2-5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385BDE4-2-5?
LM385BDE4-2-5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385BDE4-2-5 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 LM385BDE4-2-5?
For technical support, including LM385BDE4-2-5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385BDE4-2-5 requirements.
6.How does Aetrix verify that LM385BDE4-2-5 is sourced from the original manufacturer or authorized distributors?
All LM385BDE4-2-5 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 LM385BDE4-2-5 meets industry standards.
7.What is the process for return or replacement of LM385BDE4-2-5?
All LM385BDE4-2-5 units undergo pre-shipment inspection (PSI). If there is an issue with LM385BDE4-2-5, 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 LM385BDE4-2-5 part is unused and in its original packaging.
Return procedure for LM385BDE4-2-5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM385BDE4-2-5 Tags
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