My Inquiry
My Account
Texas Instruments LM385BM
- Part No.:
- LM385BM
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM385BM.pdf
- Description:
- IC VREF SHUNT ADJ 1% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,920
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM385BM from Texas Instruments is a 3-terminal adjustable micropower band-gap voltage reference diode, operating from 1.24 V to 5.30 V with 1% initial tolerance, 1 Ω dynamic impedance, and 30 ppm/°C max average temperature coefficient over 0°C to 70°C. It serves as a precision shunt reference in battery-powered meters, low-power regulators, and analog signal conditioning circuits.
For engineers reviewing the LM385BM datasheet, LM385BM pinout, LM385BM application, or LM385BM equivalent, this page delivers verified specifications, SOIC-8 package details, real-world use cases, and validated alternative options for precision voltage reference design and replacement planning.
Technical Context
The LM385BM implements a band-gap reference core using only transistors and resistors-enabling low noise, excellent long-term stability, and tolerance to capacitive loading. Its 3-terminal shunt topology requires external resistive feedback to set output voltage between 1.24 V and 5.30 V.
It operates across 10 μA to 20 mA anode current, supports reverse-biased operation up to 30 mA, and maintains regulation with minimal dropout-making it suitable for low-current shunt regulator and precision level-detection applications where supply headroom is constrained.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage Range | 1.24 V to 5.30 V - Adjustable via external resistor divider; enables flexible precision reference generation without fixed-voltage constraints. |
| Initial Tolerance | ±1% - Tight factory-trimmed accuracy at 100 μA, reducing need for post-assembly calibration in production test. |
| Dynamic Impedance | 1 Ω - Low AC output impedance ensures stable reference under varying load or transient conditions, critical for ADC reference and comparator thresholding. |
| Temperature Coefficient | 30 ppm/°C (max) - Predictable drift over 0°C to 70°C supports reliable performance in commercial-grade instrumentation and sensor interfaces. |
| Operating Current Range | 10 μA to 20 mA - Ultra-low minimum current extends battery life in portable devices; wide range allows compatibility with legacy and modern bias networks. |
| Output Noise (10 Hz–10 kHz) | 50 μVRMS at VREF, 170 μVRMS at 5.3 V - Low broadband noise preserves signal integrity in high-resolution data acquisition systems. |
| Long-Term Stability | 20 ppm (1000 hr @ 100°C) - Minimal aging drift ensures reference accuracy retention over product lifetime without recalibration. |
Pinout & Package
LM385BM is housed in an 8-pin SOIC package (Package Drawing D), with thermal resistance θJA = 170°C/W (0.125″ leads). The device uses a 3-terminal shunt configuration: Anode, Cathode, and Adjust (pin 2, 3, and 4 per TI SOIC pinout).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Pin 2) | Current sink input | Primary current path into device; connects to ground or low-impedance return when used in shunt mode. |
| Cathode (Pin 3) | Reference output node | Provides regulated voltage; connected to feedback network and load; must be decoupled for stability. |
| Adjust (Pin 4) | Feedback input | Connects to resistor divider that sets output voltage; internal band-gap reference connects here for adjustment. |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive load tolerance | Stable with >10 nF output capacitance-eliminates need for isolation resistors in noisy environments or long trace layouts. |
| Micropower operation | 10 μA minimum operating current-enables multi-year battery life in handheld multimeters and remote sensors. |
| Low-noise band-gap core | 50 μVRMS wideband noise-supports 16-bit+ ADC reference accuracy without external filtering. |
| On-chip trimming | Factory-set 1% initial tolerance-reduces BOM count and eliminates manual trim potentiometers in production assemblies. |
| Wide current compliance | 20 mA max operating current-allows direct replacement of older references (e.g., TL431-based designs) with tighter tolerance and lower drift. |
Applications
| Precision Portable Multimeter | Battery-Powered Sensor Signal Chain |
|---|---|
Use Scenario: Handheld digital multimeter requiring stable 2.5 V reference for 3½-digit ADC conversion across 0°C–50°C ambient. IC Role / Device Role / Timing Role: Shunt voltage reference providing excitation and scaling for analog front-end and ADC reference input. Use Value: 1% initial tolerance and 30 ppm/°C TC ensure <±0.1% full-scale error without field recalibration over operating temperature. |
Use Scenario: Low-power environmental sensor node (temperature/humidity) powered by coin cell, transmitting data every 5 minutes. IC Role / Device Role / Timing Role: Precision reference for sensor excitation and ADC reference in intermittent-sampling architecture. Use Value: 10 μA minimum operating current extends usable battery life beyond 3 years while maintaining ±0.5% measurement accuracy. |
| Programmable Shunt Regulator | Voltage Level Detector |
Use Scenario: 5 V rail monitor circuit detecting undervoltage condition below 4.75 V in industrial control module. IC Role / Device Role / Timing Role: Adjustable shunt reference feeding comparator input to trigger reset or alarm when supply drops. Use Value: Adjustable 1.24–5.30 V range enables exact trip point setting without external gain stages or resistor matching. |
Use Scenario: Centigrade thermometer circuit generating 10 mV/°C output using LM385BM as stable 2.5 V reference for op-amp scaling. IC Role / Device Role / Timing Role: Fixed reference source establishing known voltage offset and gain scaling factor in linearized analog output stage. Use Value: Low 50 μVRMS noise and 20 ppm/1000 hr stability preserve ±0.2°C accuracy over 5-year deployment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACDR | 2.495 V fixed reference (non-adjustable); higher 0.2 Ω dynamic impedance; 500 μA min cathode current. | Requires external resistor network to emulate adjustable behavior; unsuitable for sub-100 μA micropower designs. | Select when fixed 2.5 V reference suffices and higher current drive is needed; avoid for battery-critical or ultra-low-IQ use. |
| LM4040CIM3-ADJ | Adjustable (1.235–10 V); 0.2% initial tolerance; 20 ppm/°C TC; 60 μA min operating current. | Higher accuracy and lower TC, but 6× higher minimum current limits use in <100 μA systems. | Prefer for metrology-grade accuracy where power budget permits; LM385BM remains optimal for <20 μA operation. |
Compared with TL431ACDR and LM4040CIM3-ADJ, the LM385BM uniquely balances 1% tolerance, 10 μA minimum current, and 30 ppm/°C TC in SOIC-8-making it the only choice for cost-sensitive, battery-operated commercial instruments needing adjustable reference without sacrificing stability or longevity.
Availability
LM385BM is available at Aetrix Electronics and suitable for precision portable meters, battery-powered sensor nodes, programmable shunt regulators, and voltage level detectors requiring stable component supply across commercial temperature ranges.
Supply support for LM385BM 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, scalability, and broad application support.
The LM385 series belongs to TI's precision voltage reference product line, designed specifically for micropower, adjustable shunt reference applications in commercial-grade instrumentation, portable test equipment, and low-power analog signal chains.
FAQ
What is the operating temperature range for LM385BM?
The LM385BM is rated for operation from 0°C to 70°C, consistent with its commercial-grade classification. This range is explicitly defined in TI's SNVS741F datasheet and confirmed in the PACKAGE OPTION ADDENDUM, where "Op Temp (°C)" for LM385BM/NOPB and LM385BMX/NOPB is listed as "0 to 70". Operation outside this range may result in unguaranteed performance or parametric shift.
Does LM385BM require an external capacitor for stability?
No, the LM385BM does not require an external capacitor for stability. TI's datasheet states it is "tolerant of capacitive loading", and typical applications (e.g., Figure 17–20) show direct connection to loads without series isolation resistors or bypass caps. Its internal design accommodates >10 nF output capacitance, simplifying layout in space-constrained PCBs.
What is the pin configuration of LM385BM in SOIC-8 package?
The LM385BM uses pins 2 (Anode), 3 (Cathode), and 4 (Adjust) in the SOIC-8 package (Drawing D). Pins 1, 5–8 are NC (no connect) per TI's functional description and schematic diagram. This 3-terminal shunt configuration matches the TO-92 and SOIC variants of the LM385 family, preserving design reuse across packages.
Can LM385BM replace LM385BXZ in a TO-92 design?
LM385BM can functionally replace LM385BXZ as an adjustable shunt reference, but mechanical and thermal differences exist: LM385BM is SOIC-8 (θJA = 170°C/W), while LM385BXZ is TO-92 (θJA = 440°C/W). PCB redesign is required due to different footprint, pin count, and thermal dissipation characteristics-no drop-in replacement is possible without layout changes.
What is the maximum reverse current rating for LM385BM?
The absolute maximum reverse current for LM385BM is 30 mA, as specified in the Absolute Maximum Ratings table of SNVS741F. Exceeding this value risks permanent damage. In normal shunt regulator operation, reverse current equals the sum of load current and reference bias current, so design must ensure total reverse current stays ≤30 mA under worst-case conditions.
LM385BM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tube
- Product Status:
- Obsolete
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 1.24V
- Voltage - Output (Max):
- 5.3 V
- Current - Output:
- 20 mA
- Tolerance:
- ±1%
- Temperature Coefficient:
- 150ppm/°C
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- 50µVrms
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 55 µA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LM385BM FAQ
1.How can I place an order for LM385BM through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385BM 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 LM385BM reliable?
The price and inventory of LM385BM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM385BM is usually 5 days.
3.What payment methods are accepted for LM385BM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385BM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385BM?
LM385BM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385BM 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 LM385BM?
For technical support, including LM385BM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385BM requirements.
6.How does Aetrix verify that LM385BM is sourced from the original manufacturer or authorized distributors?
All LM385BM 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 LM385BM meets industry standards.
7.What is the process for return or replacement of LM385BM?
All LM385BM units undergo pre-shipment inspection (PSI). If there is an issue with LM385BM, 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 LM385BM part is unused and in its original packaging.
Return procedure for LM385BM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM385BM Tags
-
TL431AIDBZR
Texas Instruments
-
TL431BQDBZR
Texas Instruments
-
AN431AN-ATRG1
Diodes Incorporated
-
LM4040CYM3-2.5-TR
Microchip Technology
-
LM4040CYM3-4.1-TR
Microchip Technology
-
LM4040EIM3-2.5/NOPB
Texas Instruments
-
AZ431LBNTR-G1
Diodes Incorporated
-
LM4040D20IDBZR
Texas Instruments
-
LM4041DIM3-ADJ/NOPB
Texas Instruments
-
LM4040DIM3X-2.5/NOPB
Texas Instruments
-
LM4040DIM3-2.5/NOPB
Texas Instruments
-
AZ431LANTR-G1
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
