LP38691SD-ADJ/NOPB - 500mA 10V Adjustable LDO | Texas Instruments
N.º da peça: LP38691SD-ADJ/NOPB ✓ AtivoLP38691SD-ADJ/NOPB Visão geral
A low-dropout regulator, or LDO, is a voltage regulator that maintains a relatively stable output voltage even when its input voltage is only slightly higher than the required output. LDOs belong to the linear-regulator and voltage-regulator categories within power-management semiconductors. They are especially useful when low output ripple, simple regulation, and predictable startup behavior are more important than conversion efficiency.
The LP38691SD-ADJ/NOPB provides a 2% precision reference, a 250 mV dropout voltage at 500 mA with a 5 V output, and compatibility with ultra-low-ESR ceramic capacitors. Its low-dropout architecture makes it suitable for 3.3 V, 5 V, and other regulated rails where the available input-to-output headroom is limited. The 6-WSON package also supports compact PCB layouts, although thermal design remains important at sustained high load.
The adjustable version uses external resistors to set the output voltage, making it flexible for laboratory supplies, embedded systems, industrial controllers, and sensor interfaces. Compared with a switching regulator, an LDO generally introduces less switching ripple and requires fewer external components, although power dissipation rises with the difference between input and output voltage. The regulator should be paired with adequate input and output capacitance according to the manufacturer application guidance.
Typical applications include low-noise analog rails, communications modules, industrial control boards, portable equipment, and embedded processors. When designing with this part, verify the maximum power dissipation, confirm the output-voltage resistor network, and keep input and output capacitors close to the corresponding pins. This page combines verified manufacturer and distributor information with practical application guidance and replacement considerations for engineers evaluating this regulator.
Alternativas drop-in para LP38691SD-ADJ/NOPB — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Variantes desta série
Modelos da mesma série compatíveis como drop-in com LP38691SD-ADJ/NOPB (mesmo formato e footprint) — diferindo em Dropout Voltage, Input Voltage Range, Maximum Output Current, Operating Temperature Range, Output Voltage Range.
LP38691SD-ADJ
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
LP38692SD-ADJ
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
LP38691QSDX-ADJ/NOPB
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
LP38693-ADJ
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
LP38691SD-ADJ/NOPB Classificações máximas e características elétricas
| Product Type | Positive adjustable low-dropout CMOS linear regulator |
| Corrente máxima de saída | 500 mA |
| Faixa de tensão de entrada | 2.7 V to 10 V |
| Faixa de tensão de saída | 1.25 V to 9 V |
| Tensão de dropout | 250 mV at 500 mA and VOUT = 5 V |
| Reference Voltage Accuracy | 2% precision reference |
| Output Capacitor Stability | Stable with ultra-low-ESR ceramic output capacitors |
| Encapsulamento | 6-WSON (NGG), 3 x 3 mm |
| Número de pinos | 6 pins |
| Faixa de temperatura de operação | -40 C to 125 C |
| Tipo de montagem | Surface mount |
| Regulator Topology | Linear regulator |
| Output Polarity | Positive |
| Adjustability | Adjustable output |
| Pino de habilitação | Not specified in the supplied verified data |
| Status RoHS | RoHS compliant |
| Lead-Free Status | Lead free |
Configuração de pinos do LP38691SD-ADJ/NOPB
| Pino 1 | GND — Ground connection |
| Pino 2 | IN — Regulator input |
| Pino 3 | OUT — Regulator output |
| Pino 4 | NC — Not connected |
| Pino 5 | NC — Not connected |
| Pino 6 | EP — Exposed thermal pad; verify connection to ground or thermal plane in the datasheet |
Aplicações típicas
LP38691SD-ADJ/NOPB é adequado para 6 aplicaçãos: 3.3 V Embedded Processor Rail, Industrial Control Board Regulation, Low-Noise Analog Supply, Communication Module Power, Portable and Battery-Powered Equipment, Laboratory and Test Equipment.
3.3 V Embedded Processor Rail
LP38691SD-ADJ/NOPB is suitable for producing a 3.3 V rail for embedded processors, sensors, and communications logic when the input supply is only modestly above the desired output. The adjustable 1.25 V to 9 V range allows the output to be set with external resistors, while the 500 mA rating supports moderate digital and analog loads. Its low-dropout architecture is useful when supply headroom is limited. Place input and output capacitors close to the device and verify the 250 mV dropout specification with design margin.
Recomendado
Industrial Control Board Regulation
The LP38691SD-ADJ/NOPB can provide a compact adjustable rail for industrial control boards containing sensors, interface circuits, and low-power controllers. Its 2.7 V to 10 V input range and -40 C to 125 C operating specification make it a candidate for extended-temperature equipment, subject to thermal and EMC validation. The 6-WSON package supports compact layouts, but designers should preserve copper around the thermal pad and calculate dissipation from the actual VIN-to-VOUT difference.
Recomendado
Low-Noise Analog Supply
For analog signal chains, LP38691SD-ADJ/NOPB can generate a local rail close to the point of use, helping isolate sensitive circuitry from upstream supply variation. The LDO topology avoids the switching ripple associated with a buck converter, while the 250 mV dropout specification supports operation with limited input headroom at a 5 V output and 500 mA. Confirm output capacitor ESR, load transient response, and thermal rise before using it in precision measurement systems.
Recomendado
Communication Module Power
LP38691SD-ADJ/NOPB is applicable to RF, communications, and data-acquisition modules that require a simple local regulator rather than a complex multi-rail power tree. Its adjustable output allows one regulator design to support several nominal rail voltages, while the 500 mA rating covers many small transceiver and control sections. The compact 6-WSON footprint helps conserve board area. Designers should verify startup behavior, decoupling, and conducted-emissions performance in the final enclosure and load configuration.
Recomendado
Portable and Battery-Powered Equipment
The regulator can serve as a post-converter rail in portable equipment where a battery or charger provides a relatively narrow voltage range. Low dropout helps preserve usable input headroom, and the adjustable output supports product variants that require different logic or sensor voltages. Because linear regulation dissipates the difference between input and output voltage, efficiency should be checked at the highest expected load. Use the lowest practical dropout headroom without violating ripple and startup requirements.
Recomendado
Laboratory and Test Equipment
LP38691SD-ADJ/NOPB is useful in laboratory instruments where a configurable low-noise supply rail is needed for analog front ends or controller cards. The adjustable output range covers common 1.25 V, 2.5 V, 3.3 V, 5 V, and other rails when enough input headroom exists. Stable operation with ceramic capacitors simplifies board assembly, while the small package helps reduce instrument footprint. Validate resistor accuracy, capacitor tolerance, line regulation, and thermal behavior across the intended output-load matrix.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para LP38691SD-ADJ/NOPB — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | LP38691SD-ADJ | LP38692SD-ADJ | LP38691QSDX-ADJ/NOPB | LP38693-ADJ |
|---|---|---|---|---|---|
| Product Type | Adjustable low-dropout linear regulator | Adjustable low-dropout linear regulator | Adjustable low-dropout linear regulator | Automotive-family adjustable regulator | 500 mA low-dropout CMOS regulator |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 6-WSON (NGG) | 6-WSON (NGG) | 6-WSON family context | 6-WSON family context | 6-WSON family context |
| RoHS Status | Compliant | RoHS-compliant family device | RoHS status requires verification | RoHS status requires verification | RoHS status requires verification |
Principais diferenciais
- Adjustable output supports multiple rail settings (vs LP38691SD-ADJ)
- Low-dropout operation supports constrained input headroom (vs LP38693-ADJ)
- Compact WSON implementation for space-constrained boards (vs LP38691QSDX-ADJ/NOPB)
- Ceramic-capacitor-compatible regulation (vs LP38692SD-ADJ)
Notas de projeto
Estimated: use P = (VIN - VOUT) × IOUT to estimate linear-regulator dissipation. At 5.5 V input, 3.3 V output, and 500 mA load, the estimated loss is 1.1 W. Check the WSON exposed-pad copper area and thermal resistance against the ambient temperature and maximum junction temperature; the supplied data does not specify theta-JA.
Place the input and output capacitors close to the LP38691SD-ADJ/NOPB pins to minimize loop area and supply impedance. Preserve a continuous thermal path through the exposed pad and use the footprint and land pattern specified by Texas Instruments. Confirm the exposed-pad connection and assembly requirements from the manufacturer package drawing before release to manufacturing.
Do not assume that the 250 mV dropout specification applies without the stated 500 mA and 5 V output conditions. Include resistor tolerance, load transient margin, ambient temperature, and input ripple when setting the operating point. Also verify the selected capacitor voltage rating and ESR characteristics, because stable ceramic-capacitor operation is a specific device feature rather than a universal regulator requirement.
Keep sensitive analog ground returns separate from high-current return paths where practical, and connect the regulator ground and exposed pad to a low-impedance ground plane. Route high-current output current through copper that does not share narrow traces with precision signal paths. Validate the final layout for voltage-drop-induced regulator behavior and thermal performance using worst-case load and supply conditions.
Informações de conformidade
The supplied comparison data identifies RoHS compliance and lead-free status. The supplied manufacturer product information does not establish REACH, halogen-free, or conflict-minerals status for this exact ordering code, so those fields remain unknown. AEC-Q100 status is not specified for the standard LP38691SD-ADJ/NOPB device.
