My Inquiry
My Account
Texas Instruments LM385PSR-1-2
- Part No.:
- LM385PSR-1-2
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
LM385PSR-1-2.pdf
- Description:
- IC VREF SHUNT 2% 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:4,892
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM385PSR-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 (0°C to 70°C). It serves as a precision shunt reference in portable test instruments and battery-operated analog signal conditioning circuits.
For engineers reviewing the LM385PSR-1-2 datasheet, LM385PSR-1-2 pinout, LM385PSR-1-2 application, or LM385PSR-1-2 equivalent, key selection criteria include its 15 μA minimum operating current, 1.235 V initial tolerance (±1.0%), low broadband noise (60 μV, 10 Hz–10 kHz), and tolerance of capacitive loading without external compensation.
Technical Context
The LM385PSR-1-2 implements a floating shunt topology with internal band-gap core, high-gain amplifier, and shunt pass element - enabling stable regulation in both positive and negative reference configurations. Its on-chip frequency compensation ensures stability with arbitrary capacitive loads, eliminating need for external phase compensation.
It operates exclusively in fixed-voltage reference mode with no adjustability; regulation initiates only when cathode current exceeds 15 μA, and it maintains tight voltage accuracy across 0°C to 70°C ambient via trimmed curvature correction and low thermal hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Reference Voltage | 1.235 V at 25°C - defines precise bias point for ADC references and sensor excitation circuits |
| Initial Voltage Tolerance | ±1.0% - enables single-supply 12-bit system calibration without trimming |
| Tempco (αVZ) | ±20 ppm/°C - ensures ≤0.25 mV drift over 0°C to 70°C operating range |
| Reference Impedance | 1.5 Ω max (full temp range) - minimizes load-induced error in high-precision ratiometric measurements |
| Min Operating Current | 15 μA - supports ultra-low-power wake-up circuits and energy-harvesting systems |
| Broadband Noise | 60 μV RMS (10 Hz–10 kHz) - suitable for 16-bit SAR ADC reference without additional filtering |
| Long-Term Stability | ±20 ppm/khr - guarantees <0.1% output shift over 10-year field deployment |
Pinout & Package
LM385PSR-1-2 is supplied in an 8-pin SOIC package (package drawing D, body size 4.90 mm × 3.91 mm, max height 1.75 mm) with standard JEDEC MS-012AA footprint. Pin 1 is cathode; pin 2 is anode; pins 3–8 are NC (no internal connection).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Pin 1) | Shunt current/voltage input | Current-sink node where regulated 1.235 V appears relative to anode; must be driven by external current source |
| Anode (Pin 2) | Common reference node | Typically connected to system ground or negative rail; defines return path for reference current |
| Pins 3–8 | No internal connection | Electrically isolated; may be left unconnected or tied to ground for mechanical stability only |
Key Features
| Feature | Design Value |
|---|---|
| Floating shunt architecture | Enables use in high-side, low-side, and negative-reference topologies without level-shifting circuitry |
| Capacitive-load immunity | Stable operation with ≥10 µF ceramic bypass capacitor directly on cathode - eliminates need for series resistor or RC snubber |
| Micropower operation | 15 µA minimum current allows integration into sub-µA sleep-mode subsystems with negligible quiescent drain |
| Low-noise band-gap core | 60 µV RMS noise (10 Hz–10 kHz) supports high-resolution data acquisition without external low-noise op-amp buffering |
| On-chip curvature-trimmed voltage | ±20 ppm/°C tempco achieved via laser-trimmed resistor network - avoids external compensation components |
Applications
| Portable Test Instruments | Battery-Operated Systems |
|---|---|
Use Scenario: Handheld multimeter front-end requiring stable 1.2 V reference for autoranging ADC and display driver bias. IC Role / Device Role / Timing Role: Shunt voltage reference providing ratiometric scaling for 16-bit sigma-delta ADC and LCD segment bias generation. Use Value: Enables >100-hour battery life while maintaining ±0.1% measurement accuracy across 0°C–50°C ambient due to low 15 µA min current and ±20 ppm/°C tempco. | Use Scenario: Wireless sensor node using coin-cell battery, where reference must operate continuously during deep-sleep cycles. IC Role / Device Role / Timing Role: Precision shunt reference powering low-power op-amp comparators and microcontroller ADC reference input. Use Value: Delivers stable 1.235 V output at 15 µA, extending shelf-life-equivalent runtime by minimizing quiescent current overhead in always-on monitoring functions. |
| Current-Loop Instrumentation | Panel Meters |
Use Scenario: 4–20 mA transmitter with HART modulation, requiring stable reference for DAC output scaling and loop diagnostics. IC Role / Device Role / Timing Role: Two-terminal shunt reference establishing accurate 1.235 V threshold for current-sense amplifier gain setting and fault detection thresholds. Use Value: 1.5 Ω max impedance ensures <10 µV error under 1 mA load variation - critical for 0.1% loop accuracy compliance. | Use Scenario: Industrial panel meter with analog bar-graph display and digital readout sharing common reference rail. IC Role / Device Role / Timing Role: Central voltage reference supplying identical 1.235 V to analog meter movement driver and microcontroller ADC reference. Use Value: Tight ±1.0% initial tolerance and long-term stability eliminate need for periodic recalibration in factory-floor environments. |
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 1.235 V nominal, ±1.0% tolerance, but rated for 0°C–70°C only; identical SOIC-8 package and pinout | Identical functional behavior; differs only in device marking and orderable suffix | Select LM385BDR-1-2 if TI's B-grade binning (tighter tempco distribution) is required for high-volume production consistency |
| REF3012AIDBZR | 1.2 V output, ±0.2% initial tolerance, 50 ppm/°C tempco, 50 µA min current, SOT-23-3 package | Higher accuracy but higher power; not pin-compatible; requires PCB redesign | Choose REF3012AIDBZR only when ±0.2% absolute accuracy outweighs 3.5× higher quiescent current and layout change cost |
Compared with LM385BDR-1-2, LM385PSR-1-2 offers identical electrical performance but different tape-and-reel packaging (2,500 pcs/reel vs 2,500 pcs/reel) and marking; versus REF3012AIDBZR, it trades tighter initial tolerance for 3.3× lower minimum current and proven capacitive-load robustness in legacy designs.
Availability
LM385PSR-1-2 is available at Aetrix Electronics and suitable for portable test instruments, battery-operated systems, and current-loop instrumentation requiring stable component supply with guaranteed long-term continuity.
Supply support for LM385PSR-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 leadership in precision analog ICs since 1958.
The LM385 family was designed specifically for micropower, two-terminal shunt voltage reference applications in portable, battery-constrained, and industrial measurement systems - prioritizing low current, wide temperature stability, and capacitive-load immunity.
FAQ
What is the minimum cathode current required for regulation in LM385PSR-1-2?
The LM385PSR-1-2 requires a minimum cathode current of 15 μA to achieve proper regulation and maintain its specified 1.235 V output accuracy. Below this threshold, the reference voltage becomes unstable and deviates significantly from nominal. This value is confirmed in the Electrical Characteristics table of the SLVS075J datasheet under "Minimum reference current" for LM385-1.2 devices. Operating LM385PSR-1-2 at exactly 15 μA is valid but leaves no margin for temperature or aging drift; design best practice recommends ≥20 μA for robustness.
Is LM385PSR-1-2 pin-compatible with LM385DR-1-2?
Yes, LM385PSR-1-2 is pin-compatible with LM385DR-1-2: both use the same SOIC-8 package (drawing D), share identical pin 1 (cathode) and pin 2 (anode) assignments, and have pins 3–8 designated as NC. The "PSR" suffix denotes a specific tape-and-reel packaging variant (2,500 pcs/reel, Q1 pin 1 quadrant), while "DR" indicates standard SOIC-8 tape-and-reel. No PCB layout changes are needed when substituting between these variants, as mechanical and electrical interfaces are fully aligned per TI's PACKAGE OPTION ADDENDUM.
What is the maximum capacitive load the LM385PSR-1-2 can drive without oscillation?
The LM385PSR-1-2 is explicitly characterized for stable operation with ≥10 µF ceramic bypass capacitance on the cathode node, as validated in Layout Guidelines (Section 11.1) and Typical Characteristics (Figure 7). Its internal frequency compensation ensures unconditional stability across all capacitive loads within its operating current range (15 μA to 20 mA), eliminating need for series resistance or external compensation networks. This capability is a defining feature of the LM385 family and distinguishes it from older shunt references requiring careful load capacitance limits.
Does LM385PSR-1-2 support operation below 0°C?
No, LM385PSR-1-2 is specified for operation from 0°C to 70°C only, consistent with the LM385-1.2 grade (not the wider-range LM285-1.2). The Electrical Characteristics table explicitly states "Full Range: 0°C to 70°C" for LM385-1.2 parameters including tempco, reference impedance, and noise. Operation below 0°C is outside guaranteed specifications and may result in increased tempco deviation (>±20 ppm/°C), elevated reference impedance, or reduced long-term stability - TI does not characterize or warrant performance in sub-zero conditions for this variant.
How does the LM385PSR-1-2 reference impedance affect accuracy in a 12-bit ADC application?
In a 12-bit ADC application with 3.3 V full-scale range, LSB = 0.8 mV. LM385PSR-1-2's 1.5 Ω max reference impedance introduces ≤1.5 mV error when loaded with 1 mA - exceeding one LSB. Therefore, for 12-bit accuracy, load current must be limited to ≤533 µA (1.5 Ω × 533 µA = 0.8 mV). This is easily achieved using high-impedance buffer op-amps or selecting ADCs with reference input impedance >100 kΩ. The low impedance ensures minimal error contribution when properly interfaced, making LM385PSR-1-2 suitable for precision metrology-grade designs.
LM385PSR-1-2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.209", 5.30mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- 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-SO
LM385PSR-1-2 FAQ
1.How can I place an order for LM385PSR-1-2 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385PSR-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 LM385PSR-1-2 reliable?
The price and inventory of LM385PSR-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 LM385PSR-1-2 is usually 5 days.
3.What payment methods are accepted for LM385PSR-1-2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385PSR-1-2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385PSR-1-2?
LM385PSR-1-2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385PSR-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 LM385PSR-1-2?
For technical support, including LM385PSR-1-2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385PSR-1-2 requirements.
6.How does Aetrix verify that LM385PSR-1-2 is sourced from the original manufacturer or authorized distributors?
All LM385PSR-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 LM385PSR-1-2 meets industry standards.
7.What is the process for return or replacement of LM385PSR-1-2?
All LM385PSR-1-2 units undergo pre-shipment inspection (PSI). If there is an issue with LM385PSR-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 LM385PSR-1-2 part is unused and in its original packaging.
Return procedure for LM385PSR-1-2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM385PSR-1-2 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…
