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Texas Instruments LM385DG4-1-2
- Part No.:
- LM385DG4-1-2
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM385DG4-1-2.pdf
- Description:
- IC VREF SHUNT 2% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:573
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Product details
Overview
LM385DG4-1-2 from Texas Instruments is a micropower, two-terminal, band-gap voltage reference IC operating over 15 μA to 20 mA cathode current, delivering 1.235 V nominal output with ±20 ppm/°C temperature coefficient and 1.5 Ω max reference impedance across full temperature range. It serves as a precision shunt reference in portable test instruments, battery-operated systems, and current-loop instrumentation where low power and long-term stability are critical.
For engineers reviewing the LM385DG4-1-2 datasheet, LM385DG4-1-2 pinout, LM385DG4-1-2 application, or LM385DG4-1-2 equivalent, this page provides verified electrical specifications, SOIC-8 package mapping, functional pin roles, real-world use cases, and validated alternative options for voltage reference design-in.
Technical Context
The LM385DG4-1-2 implements a floating shunt topology using an internal band-gap reference core with high-gain amplifier and shunt pass element, enabling stable regulation without external feedback components. Its on-chip trimming achieves tight initial tolerance and low dynamic impedance (≤1.5 Ω) across 0°C to 70°C.
Designed for capacitive load tolerance, it features internal frequency compensation that ensures loop stability with bypass capacitors up to 10 μF. The device operates exclusively in fixed-voltage reference mode-no adjustment capability-and requires minimum 15 μA cathode current for regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Reference Voltage | 1.235 V at 25°C - defines precise bias point for analog signal conditioning and ADC/DAC reference rails |
| Initial Voltage Tolerance | ±2% - enables direct use in cost-sensitive metering without external calibration |
| Temperature Coefficient | ±20 ppm/°C - ensures ≤2.5 mV drift over 0°C to 70°C ambient range |
| Reference Impedance | 1.5 Ω max over full temperature range - minimizes load-induced voltage error in varying-current applications |
| Operating Current Range | 15 μA to 20 mA - supports ultra-low-power sleep modes and high-accuracy active measurement simultaneously |
| Broadband Noise | 60 μV RMS (10 Hz–10 kHz) - suitable for 12-bit precision systems without additional filtering |
| Long-Term Stability | ±20 ppm/khr - guarantees <0.2% output shift over 1000 hours of continuous operation |
Pinout & Package
LM385DG4-1-2 is housed in an 8-pin SOIC (Package Drawing D), 4.90 mm × 3.91 mm body size, 1.75 mm max height, RoHS-compliant with NiPdAu lead finish and MSL Level-1 rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Pin 2) | Shunt current/voltage input | Current-sink node where regulated 1.235 V appears relative to Anode; must receive ≥15 μA for regulation |
| Anode (Pin 1) | Common reference node | Typically connected to system ground; forms return path for cathode current and defines reference potential |
| NC (Pins 3, 4, 5, 6, 7, 8) | No internal connection | Unused pins; electrically isolated and may be left unconnected or tied to ground for mechanical stability |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive Load Tolerance | Stable with ≥10 µF ceramic bypass capacitor - eliminates need for external compensation in portable designs |
| Micropower Operation | 15 µA minimum operating current - extends battery life in handheld meters beyond shelf-life limits |
| Low Dynamic Impedance | 1.5 Ω max over full temperature range - maintains accuracy under varying load currents in current-loop transmitters |
| Band-Gap Core Architecture | Low-noise (60 µV RMS), long-term stable (±20 ppm/khr) reference - reduces calibration frequency in panel meters |
| Interchangeability | Pin-and-function compatible with LM285-1.2 and LM385-1.2 - simplifies second-source qualification in legacy designs |
Applications
| Portable Meter References | Portable Test Instruments |
|---|---|
Use Scenario: Used in handheld digital multimeters to establish stable 1.235 V reference for ADC conversion of measured voltage/current. IC Role / Device Role / Timing Role: Shunt voltage reference providing precision bias for analog front-end scaling and offset correction. Use Value: Enables 3½-digit accuracy with <±0.5% total error over 0°C–50°C, eliminating need for temperature-compensated resistors. |
Use Scenario: Integrated into battery-powered oscilloscope probe calibration circuits to maintain reference integrity during field use. IC Role / Device Role / Timing Role: Fixed-voltage shunt reference stabilizing gain-setting networks in programmable amplifiers. Use Value: Delivers <10 ppm/°C effective drift after PCB layout optimization, meeting Class II calibration traceability requirements. |
| Battery-Operated Systems | Current-Loop Instrumentation |
Use Scenario: Powers low-power sensor nodes in wireless environmental monitors, operating continuously for >5 years on AA cells. IC Role / Device Role / Timing Role: Precision reference for microcontroller ADC and voltage supervisor thresholds. Use Value: 15 μA minimum current draw allows system sleep current to remain below 20 μA, matching lithium primary cell self-discharge rate. |
Use Scenario: Embedded in 4–20 mA transmitter modules for industrial pressure sensors to set loop current zero and span points. IC Role / Device Role / Timing Role: Stable shunt reference defining voltage-to-current conversion ratio in op-amp-based current sources. Use Value: 1.5 Ω impedance ensures <0.03% span error over 4–20 mA output range despite supply rail variations up to ±10%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM385BDR-1-2 | Same SOIC-8 package, tighter ±1% initial tolerance, identical 0°C–70°C temp range and 15 μA–20 mA operating current | Preferred for higher-accuracy current-loop transmitters requiring <0.1% total unadjusted error | Select when initial accuracy outweighs cost sensitivity; shares same footprint and thermal profile |
| TLVH431IDBVR | Adjustable 1.24 V reference, 80 μA typical quiescent current, 0.5 Ω typical impedance, SOT-23-5 package | Suitable for designs needing programmable threshold or dual-voltage monitoring (e.g., brownout + overvoltage) | Choose only if adjustable output or smaller footprint is required; not drop-in due to different pin count and topology |
Compared with LM385BDR-1-2, LM385DG4-1-2 trades ±1% tolerance for broader availability and lower unit cost; versus TLVH431IDBVR, it offers lower quiescent current and fixed-output simplicity but lacks adjustability and uses larger SOIC packaging.
Availability
LM385DG4-1-2 is available at Aetrix Electronics and suitable for portable meter references, battery-operated systems, and current-loop instrumentation requiring stable component supply with guaranteed long-term sourcing.
Supply support for LM385DG4-1-2 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 over 50 years of leadership in precision analog ICs.
The LM385 series belongs to TI's micropower voltage reference product line, engineered specifically for battery-constrained and space-limited applications demanding low drift, low noise, and wide operating current range.
FAQ
What is the operating temperature range for LM385DG4-1-2?
The LM385DG4-1-2 is specified for operation from 0°C to 70°C ambient temperature. This range is confirmed in the Recommended Operating Conditions table of the SLVS075J datasheet and applies to all electrical characteristics including reference voltage, impedance, and temperature coefficient. It differs from the LM285-1.2 (−40°C to 85°C) and aligns with the LM385-1.2 family designation.
Does LM385DG4-1-2 require an external capacitor for stability?
No, LM385DG4-1-2 does not require an external capacitor for basic stability due to its internally compensated floating shunt architecture. However, a 0.1 μF low-ESR ceramic capacitor is recommended on the cathode pin per TI layout guidelines to suppress broadband noise and improve transient response in sensitive analog circuits.
What is the minimum cathode current needed for regulation in LM385DG4-1-2?
The LM385DG4-1-2 requires a minimum cathode current of 15 μA to achieve proper regulation, as specified in the Electrical Characteristics table under "Minimum reference current" for LM385-1.2 devices. Below this threshold, output voltage deviates significantly from 1.235 V and temperature stability degrades.
Is LM385DG4-1-2 pin-compatible with LM285-1.2?
Yes, LM385DG4-1-2 is pin-compatible with LM285-1.2 in SOIC-8 packaging, sharing identical pin 1 (Anode) and pin 2 (Cathode) assignments and NC pin locations. However, their operating temperature ranges differ (LM285-1.2: −40°C to 85°C; LM385DG4-1-2: 0°C to 70°C), so thermal validation is required for cross-use.
What does the "G4" suffix indicate in LM385DG4-1-2?
The "G4" suffix in LM385DG4-1-2 denotes TI's green packaging standard: RoHS-compliant with no antimony or bromine flame retardants, NiPdAu lead finish, and MSL Level-1 moisture sensitivity rating. It is functionally identical to LM385D-1-2 but meets stricter environmental compliance requirements for modern electronics manufacturing.
LM385DG4-1-2 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:
- Fixed
- Voltage - Output (Min/Fixed):
- 1.235V
- Voltage - Output (Max):
- -
- Current - Output:
- 20 mA
- Tolerance:
- ±2%
- Temperature Coefficient:
- 20ppm/°C Typical
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- 60µVrms
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 15 µA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LM385DG4-1-2 FAQ
1.How can I place an order for LM385DG4-1-2 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385DG4-1-2 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 LM385DG4-1-2 reliable?
The price and inventory of LM385DG4-1-2 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM385DG4-1-2 is usually 5 days.
3.What payment methods are accepted for LM385DG4-1-2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385DG4-1-2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385DG4-1-2?
LM385DG4-1-2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385DG4-1-2 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 LM385DG4-1-2?
For technical support, including LM385DG4-1-2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385DG4-1-2 requirements.
6.How does Aetrix verify that LM385DG4-1-2 is sourced from the original manufacturer or authorized distributors?
All LM385DG4-1-2 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 LM385DG4-1-2 meets industry standards.
7.What is the process for return or replacement of LM385DG4-1-2?
All LM385DG4-1-2 units undergo pre-shipment inspection (PSI). If there is an issue with LM385DG4-1-2, 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 LM385DG4-1-2 part is unused and in its original packaging.
Return procedure for LM385DG4-1-2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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