Texas Instruments LM385-1.2-MWC

Overview

LM385-1.2-MWC from Texas Instruments is a micropower, two-terminal, band-gap voltage reference IC operating over 15 μA to 20 mA, delivering 1.235 V nominal output with ±20 ppm/°C temperature coefficient and ≤1 Ω reference impedance at 25°C. It serves as a precision shunt reference in portable metering, battery-powered instrumentation, and current-loop systems where ultra-low power and long-term stability are critical.

For engineers reviewing the LM385-1.2-MWC datasheet, LM385-1.2-MWC pinout, LM385-1.2-MWC application, or LM385-1.2-MWC equivalent, key selection criteria include minimum cathode current (15 μA), low-noise operation (60 μV broadband), capacitive-load tolerance, and MIL-grade thermal range (–40°C to +85°C) - all verified for wafer-sale (YS) delivery format.

Technical Context

The LM385-1.2-MWC implements a floating shunt topology with internal band-gap core and high-gain amplifier driving a pass element, enabling stable regulation without external components. Its on-chip trimming achieves 1% initial voltage tolerance, while frequency compensation ensures stability across all capacitor loads - including bypass caps up to 10 μF.

It operates exclusively in fixed-voltage reference mode with no adjustability; regulation requires sourcing current into the cathode above I_Z(min) = 15 μA. The device exhibits low dynamic impedance (≤1.5 Ω over full temperature range) and long-term drift of ±20 ppm/khr at 100 μA, supporting decade-scale analog system calibration integrity.

Key Specifications

Pinout & Package

LM385-1.2-MWC is supplied in wafer-sale (YS) format - bare die without leadframe or molded package. No standardized pinout applies; electrical terminals are accessed via bond pads per TI's wafer-level specification.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar shunt voltage reference applications.

Compared with LM385B-1.2/NOPB, the LM385-1.2-MWC offers tighter initial tolerance for reduced calibration effort; versus REF191GS, it provides simpler two-terminal integration and lower quiescent current - critical for battery longevity in field-deployed nodes.

Availability

LM385-1.2-MWC is available at Aetrix Electronics and suitable for portable meter references, battery-operated systems, and current-loop instrumentation requiring stable component supply across extended product lifecycles.

Supply support for LM385-1.2-MWC 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, specializing in analog, embedded processing, and digital signal technologies for industrial, automotive, and communications markets.

The LM385 family was designed specifically for micropower, high-stability shunt voltage reference applications in portable and battery-constrained systems - emphasizing low current consumption, wide temperature operation, and capacitive-load robustness.

FAQ

What is the minimum cathode current required for regulation in the LM385-1.2-MWC?

The LM385-1.2-MWC requires a minimum cathode current of 15 μA to achieve proper regulation, as specified in its Electrical Characteristics table. This value is guaranteed over the full operating temperature range (–40°C to +85°C). Supplying less than 15 μA may result in unstable or out-of-specification reference voltage. The LM385-1.2-MWC maintains regulation up to 20 mA, making it compatible with both ultra-low-power and moderate-current applications.

Does the LM385-1.2-MWC have a defined pinout for PCB layout?

No - the LM385-1.2-MWC is supplied in wafer-sale (YS) format, meaning it is delivered as bare die without leads, package, or standardized footprint. Electrical access is via bond pads per Texas Instruments' wafer-level documentation. Engineers must design custom interconnects (e.g., wire bonding or flip-chip) and cannot use standard SOIC, TSSOP, or TO-226 land patterns. The LM385-1.2-MWC datasheet does not define a PCB-compatible pinout.

Can the LM385-1.2-MWC replace the LM385-1.2-MIL in existing designs?

The LM385-1.2-MWC shares identical electrical specifications (voltage, tempco, impedance, noise) with the LM385-1.2-MIL but differs physically: MWC is wafer-sale, while MIL is packaged (SOIC/SOP/TSSOP/TO-226). Therefore, the LM385-1.2-MWC cannot be drop-in replaced in PCBs designed for packaged versions. It is intended for hybrid or custom module integration. The LM385-1.2-MWC retains full functional equivalence where packaging is re-engineered.

What is the long-term stability performance of the LM385-1.2-MWC?

The LM385-1.2-MWC exhibits ±20 ppm/khr long-term drift when operated at 100 μA and 25°C, translating to approximately ±0.175% voltage change over 10 years. This stability is measured under controlled conditions and supports applications requiring infrequent recalibration - such as sealed environmental sensors or utility meter reference circuits. The LM385-1.2-MWC achieves this via band-gap core design and on-chip trimming, with no external components needed to maintain drift performance.

Is the LM385-1.2-MWC suitable for use with large bypass capacitors?

Yes - the LM385-1.2-MWC features internal frequency compensation that ensures stability with bypass capacitors up to at least 10 μF, as confirmed in TI's layout guidelines and typical characteristics. This eliminates the need for series damping resistors or ferrite beads commonly required with other shunt references. The LM385-1.2-MWC's capacitive-load tolerance simplifies power-supply decoupling in noise-sensitive analog circuits like precision data loggers and portable test equipment.