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Texas Instruments LM385M/NOPB
- Part No.:
- LM385M/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM385M/NOPB.pdf
- Description:
- IC VREF SHUNT ADJ 2% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,588
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Product details
Overview
LM385M/NOPB 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 instrumentation, low-power regulators, and analog signal conditioning circuits.
For engineers reviewing the LM385M/NOPB datasheet, LM385M/NOPB pinout, LM385M/NOPB application, or LM385M/NOPB equivalent, key selection criteria include its 10 μA to 20 mA operating current range, TO-92 and SOIC package options, low-noise performance (50 μVrms at VREF), and compatibility with capacitive loading without instability.
Technical Context
The LM385M/NOPB implements a band-gap reference architecture using only transistors and resistors-no op-amps or active compensation-enabling low noise, excellent long-term stability (20 ppm typical drift over 1000 hours), and inherent tolerance to capacitive loading. Its feedback current remains stable at ≤25 nA (max) across temperature and load conditions.
Designed for shunt-mode operation, it regulates by sinking variable current through an external resistor to maintain precise output voltage at the ADJ pin. The device requires no external components for basic operation and supports both fixed and adjustable configurations via two external resistors in standard applications like 10 V references or low-current shunt regulators.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage Range | Adjustable from 1.24 V to 5.30 V - enables flexible design of precision references across common system rail voltages. |
| Initial Tolerance | ±1% at 100 μA - ensures accurate voltage setting without calibration in production-grade portable meters and sensor interfaces. |
| Dynamic Impedance | 1 Ω at 100 μA - minimizes output voltage variation under changing load current, critical for high-precision ADC reference buffers. |
| Operating Current Range | 10 μA to 20 mA - supports ultra-low-power sleep modes and higher-current regulation without external buffering. |
| Temp Coefficient | 30 ppm/°C max (average) - guarantees <±2 mV drift over full 0°C–70°C industrial range for 2.5 V reference designs. |
| Output Noise | 50 μVrms (10 Hz–10 kHz, VOUT = VREF) - meets low-noise requirements for precision data acquisition front-ends. |
| Min Operating Current | 7 μA (max) at VOUT = VREF - allows stable regulation even in energy-harvesting systems with microamp-level supply capability. |
Pinout & Package
LM385M/NOPB is housed in an 8-pin SOIC (Package Drawing D), with thermal resistance θJA = 170°C/W (0.125″ leads). Pin 1 is the Cathode, Pin 2 is the Anode, and Pin 3 is the Adjust (ADJ) terminal; Pins 4–8 are NC (No Connect) per TI's official SOIC pinout for LM385 variants.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Pin 1) | Reference Output Node | Sinks regulated current; connects to system ground or feedback network to establish precise VREF at ADJ pin. |
| Anode (Pin 2) | Current Return Path | Completes shunt path; ties to positive supply rail via series resistor to set operating point and output voltage. |
| ADJ (Pin 3) | Reference Voltage Tap | Provides access to internal band-gap node; used with external resistive divider to program output voltage from 1.24 V to 5.30 V. |
| Pins 4–8 | No Connect | Unused terminals; must remain unconnected per TI specification to avoid parasitic coupling or thermal imbalance. |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive Load Tolerance | Stable with ≥1 μF ceramic output capacitance - eliminates need for external isolation resistors in noisy environments. |
| Micropower Operation | 10 μA minimum operating current - extends battery life in handheld multimeters and remote sensor nodes beyond 10 years. |
| Low Long-Term Drift | 20 ppm typical over 1000 hours - reduces recalibration frequency in field-deployed test equipment and medical monitors. |
| Wide Supply Flexibility | Operates with input-to-output differential as low as 0.5 V - enables use with Li-ion cells down to 3.0 V while maintaining 2.5 V reference. |
| ESD Robustness | 2 kV HBM rating - withstands handling in standard lab and manufacturing environments without special precautions. |
Applications
| Portable Precision Instrumentation | Battery-Powered Sensor Signal Conditioning |
|---|---|
Use Scenario: Handheld digital multimeter requiring stable 2.5 V reference for 16-bit SAR ADC over 0°C–50°C ambient. IC Role / Device Role / Timing Role: Shunt voltage reference providing excitation and conversion reference for analog front-end and ADC. Use Value: 1% initial tolerance and 30 ppm/°C tempco ensure measurement accuracy stays within ±0.1% full-scale error without factory trim. |
Use Scenario: Wireless temperature node using thermistor bridge and low-power MCU with integrated 12-bit ADC. IC Role / Device Role / Timing Role: Precision bias source for ratiometric bridge excitation and ADC reference voltage. Use Value: Micropower 10 μA operation extends CR2032 battery life to >5 years while maintaining <±1.5 mV reference error across operating temperature. |
| Low-Noise Data Acquisition Reference | Adjustable Shunt Regulator for Low-Power Supplies |
Use Scenario: Industrial DAQ module digitizing ±10 V sensor signals with 24-bit delta-sigma ADC. IC Role / Device Role / Timing Role: Ultra-low-noise (50 μVrms) reference source for ADC and PGA gain-setting resistors. Use Value: Band-gap architecture and 1 Ω dynamic impedance suppress supply-induced ripple and improve ENOB by ≥1.2 bits. |
Use Scenario: Standby power rail in smart meter ASIC requiring 3.3 V @ 5 mA from 5 V main supply with minimal quiescent loss. IC Role / Device Role / Timing Role: Adjustable shunt regulator configured for 3.3 V output using two external resistors. Use Value: 20 mA max current capability and tight 1% tolerance enable stable regulation without LDO, reducing BOM count and PCB area. |
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 |
|---|---|---|---|
| TLVH431ACDBVR | 2.5 V fixed reference (adjustable via resistor divider); 0.5% initial tolerance; 20 ppm/°C tempco; 1.25 V reference voltage. | Requires external resistors for adjustment; lower dynamic impedance (0.2 Ω); higher min current (80 μA). | Preferred when tighter tolerance and lower tempco are required, and higher operating current is acceptable. |
| MAX6008AEUR+T | Fixed 2.048 V output; 0.2% initial tolerance; 15 ppm/°C tempco; 35 μA typical quiescent current. | Not adjustable; optimized for low-noise, high-precision fixed-reference use cases only. | Select when a stable, non-adjustable reference is sufficient and sub-ppm/°C stability is critical. |
Compared with TLVH431ACDBVR and MAX6008AEUR+T, the LM385M/NOPB offers wider voltage adjustability (1.24–5.30 V) and lower minimum operating current (10 μA), making it uniquely suitable for ultra-low-power, multi-rail reference generation where flexibility and micropower coexist.
Availability
LM385M/NOPB is available at Aetrix Electronics and suitable for portable instrumentation, battery-powered sensor nodes, low-noise data acquisition systems, and adjustable shunt regulator designs requiring stable component supply across industrial and commercial temperature ranges.
Supply support for LM385M/NOPB 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 headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.
The LM385M/NOPB belongs to TI's legacy micropower voltage reference product line, designed specifically for cost-sensitive, low-power applications where precision, stability, and capacitive-load immunity are essential - including handheld test gear, sensor interfaces, and energy-efficient power management.
FAQ
What is the operating temperature range for LM385M/NOPB?
The LM385M/NOPB is rated for operation from 0°C to 70°C, matching the LM385 series specification. This industrial-grade range supports deployment in consumer electronics, smart sensors, and non-aerospace embedded systems where extended temperature operation is not required. The SOIC package (D) used in LM385M/NOPB maintains specified electrical performance across this full range, with thermal resistance θJA = 170°C/W.
Can LM385M/NOPB be used as a 2.5 V reference without external resistors?
No - the LM385M/NOPB is an adjustable shunt reference requiring two external resistors to set output voltage. For a 2.5 V reference, connect a resistor between cathode and anode (R1), and another between anode and ADJ (R2), sized per the formula VOUT = 1.24 V × (1 + R1/R2). Unlike fixed references such as LM4040, LM385M/NOPB has no internal resistor network and cannot function at a defined voltage without external configuration.
What is the maximum output current capability of LM385M/NOPB?
The LM385M/NOPB is rated for up to 20 mA of sink current, as confirmed in the Electrical Characteristics table under "Maximum Operating Current" (30 μA to 60 μA tested limits scale linearly to 20 mA). This allows it to regulate loads up to ~20 mA directly - for example, powering an op-amp bias network or driving the reference input of a 12-bit ADC - provided the external series resistor delivers sufficient headroom voltage and power dissipation is managed within SOIC thermal limits.
Does LM385M/NOPB require an output capacitor for stability?
No - the LM385M/NOPB is explicitly designed to be tolerant of capacitive loading, including ≥1 μF ceramic capacitors, without oscillation or phase margin degradation. TI's datasheet states "careful design… makes the device tolerant of capacitive loading, making it easy to use in almost any reference application." This eliminates the need for series isolation resistors often required with older references, simplifying layout and improving transient response in battery-powered systems.
How does the LM385M/NOPB differ from LM385BXZ/NOPB?
The LM385M/NOPB uses an 8-pin SOIC package (D), while LM385BXZ/NOPB uses a 3-pin TO-92 package (LP). Both share identical electrical specifications - 1% initial tolerance, 1.24–5.30 V adjustability, 0°C–70°C operation - but differ mechanically: SOIC offers better thermal performance (θJA = 170°C/W vs. 440°C/W for TO-92), higher reliability in automated assembly, and improved moisture sensitivity level (MSL Level-1 vs. N/A). LM385M/NOPB is preferred for surface-mount production; LM385BXZ/NOPB suits through-hole prototyping or space-constrained axial layouts.
LM385M/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tube
- Product Status:
- Active
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 1.24V
- Voltage - Output (Max):
- 5.3 V
- Current - Output:
- 20 mA
- Tolerance:
- ±2%
- 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
LM385M/NOPB FAQ
1.How can I place an order for LM385M/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385M/NOPB 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 LM385M/NOPB reliable?
The price and inventory of LM385M/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM385M/NOPB is usually 5 days.
3.What payment methods are accepted for LM385M/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385M/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385M/NOPB?
LM385M/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385M/NOPB 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 LM385M/NOPB?
For technical support, including LM385M/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385M/NOPB requirements.
6.How does Aetrix verify that LM385M/NOPB is sourced from the original manufacturer or authorized distributors?
All LM385M/NOPB 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 LM385M/NOPB meets industry standards.
7.What is the process for return or replacement of LM385M/NOPB?
All LM385M/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM385M/NOPB, 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 LM385M/NOPB part is unused and in its original packaging.
Return procedure for LM385M/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM385M/NOPB Tags
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