AS13985H18-T Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The AS13985H18-T is a linear voltage regulator IC manufactured by ams-OSRAM USA INC., designed to deliver a fixed 1.8V output at 150mA in a surface-mount SOT-23-5 package. This device functions as a positive fixed output regulator with integrated enable control and thermal/overcurrent protection features.

The AS13985H18-T is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity, ensure supply chain reliability, and support long-term product availability for applications requiring this specific voltage regulation topology and output specification.

Substiute Parts

AS13985H18-T

ams-OSRAM USA INC.In Stock: 998AS13985H18-T Datasheet

Current PartRFQ

LD39015M18R

STMicroelectronicsIn Stock: 161332LD39015M18R Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AS13985H18-T is determined by strict equivalence across the following critical parameters:

Mandatory Matching Parameters:

• Fixed output voltage: 1.8V
• Output current rating: 150mA minimum
• Input voltage maximum: 5.5V
• Package type: SOT-23-5 (SC-74A)
• Surface-mount configuration
• Operating temperature range: -40°C to 125°C
• Control features: Enable function
• Protection: Over-current and over-temperature protection

The LD39015M18R from STMicroelectronics meets all mandatory substitution criteria. Both devices share identical output voltage, current rating, input voltage specification, package footprint, and functional feature set. The substitute part is classified as active product status, ensuring ongoing availability and supply chain support.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: LD39015M18R

The LD39015M18R is the direct functional equivalent for the obsolete AS13985H18-T. Selection of this substitute is based on the following engineering factors:

Product Status: The LD39015M18R maintains active product status with STMicroelectronics, ensuring long-term availability, ongoing manufacturing support, and supply chain continuity. The AS13985H18-T is obsolete, making substitution necessary for new designs and ongoing production support.

Electrical Equivalence: Both devices deliver identical fixed 1.8V output at 150mA with matching input voltage specifications (5.5V maximum) and operating temperature range (-40°C to 125°C). Functional features including enable control and dual protection (over-current and over-temperature) are identical.

Package Compatibility: Both parts use the SOT-23-5 (SC-74A) surface-mount package, ensuring direct PCB footprint compatibility without layout modifications.

Compliance & Certifications: The LD39015M18R is ROHS3 compliant and carries REACH Unaffected status, meeting modern regulatory requirements. The substitute part features improved moisture sensitivity (MSL 1 versus MSL 3), providing superior reliability in storage and handling.

Performance Advantages: The LD39015M18R demonstrates improved quiescent current (50 µA versus 130 µA) and supply current (70 µA versus 250 µA), resulting in lower power consumption. PSRR performance is enhanced across both measured frequencies (65dB at 1kHz and 62dB at 10kHz versus 60dB and 55dB respectively). Dropout voltage is specified at 0.1V @ 100mA.

Frequently Asked Questions (FAQ)

Q: Can the LD39015M18R be used as a direct replacement for the AS13985H18-T without PCB modifications?

A: Yes. Both devices use the SOT-23-5 (SC-74A) package with identical pin configurations and functional features. Direct substitution on existing PCBs is possible without layout changes.

Q: What are the key differences between these two parts?

A: The primary differences are manufacturer (ams-OSRAM versus STMicroelectronics), product status (obsolete versus active), and improved performance characteristics in the LD39015M18R. The substitute offers lower quiescent and supply currents, better PSRR performance, and superior moisture sensitivity rating. All critical electrical parameters (output voltage, current, input voltage, temperature range) are identical.

Q: Is the LD39015M18R suitable for new product designs?

A: Yes. The LD39015M18R is classified as active product status with full manufacturing support. It is the appropriate choice for new designs requiring a 1.8V, 150mA linear regulator in SOT-23-5 packaging.

Q: What is the significance of the MSL rating difference?

A: The AS13985H18-T carries MSL 3 (168-hour moisture sensitivity limit), while the LD39015M18R carries MSL 1 (unlimited). MSL 1 indicates superior moisture resistance and provides greater flexibility in storage, handling, and manufacturing processes without requiring special precautions.

Q: Are there any compliance or regulatory differences?

A: The LD39015M18R is ROHS3 compliant and carries REACH Unaffected certification. Both parts share identical ECCN (EAR99) and HTSUS (8542.39.0001) classifications. The substitute part meets current regulatory requirements for modern applications.

Q: What is the impact of improved PSRR in the LD39015M18R?

A: Power Supply Rejection Ratio (PSRR) measures the regulator's ability to reject noise from the input supply. The LD39015M18R provides 5dB improvement at 1kHz (65dB versus 60dB) and 7dB improvement at 10kHz (62dB versus 55dB), resulting in cleaner output voltage under noisy supply conditions.

Q: Are pin assignments identical between these parts?

A: Both devices use the SOT-23-5 package. Verify pin assignments in the respective datasheets to confirm identical functionality mapping before implementation.