LP2985AITLX-1.8 - 150mA, 1.8V Fixed LDO Regulator | Texas Instruments
Артикул: LP2985AITLX-1.8 ✓ АктивенLP2985AITLX-1.8 Обзор
An LDO (Low-Dropout) linear regulator is a type of voltage regulator that maintains a stable output voltage even when the input voltage is very close to the output voltage, eliminating the need for large input-to-output headroom required by older NPN-pass regulators. Within the broader semiconductor hierarchy, an LDO sits below switching regulators in the power management IC family, trading conversion efficiency for noise performance, simplicity, and a small PCB footprint. The LP2985 specifically targets applications where a clean, low-noise 1.8 V rail is required directly from a higher-voltage source such as a 3.3 V or 5 V system rail.
Key features include a low quiescent current of approximately 850 µA at full load, an active-high shutdown pin that drops quiescent current to less than 1 µA, internal current limit and thermal shutdown protection, and a logic-level CMOS enable input. The LP2985AITLX-1.8 is the 'A' tolerance grade (1.0%) fixed-output variant with the 'TL' micro SMD ball-grid package, intended for compact, height-constrained surface-mount designs.
The regulator uses a low-noise PNP pass architecture with a precision bandgap reference, achieving typical output noise around 30 µVrms and excellent line/load transient response. The internal protection blocks include reverse-battery protection, foldback current limit, and thermal shutdown with hysteresis for fault-tolerant operation.
Typical applications include powering low-voltage digital logic cores (FPGA/ASIC 1.8 V rails), USB peripherals, post-regulation after a switching converter, battery-powered portable devices, and point-of-load regulation for noise-sensitive analog blocks. The wide 16 V maximum input allows direct operation from a 9 V or 12 V system rail.
When designing with the LP2985AITLX-1.8, ensure input and output ceramic capacitors are placed as close as possible to the device pins, and verify that the application's worst-case dropout rate fits within the thermal limit of the small micro SMD package.
Аналоги без доработки для LP2985AITLX-1.8 — тот же корпус, pin-to-pin совместимость. Компоненты в других корпусах, требующие переработки PCB, исключены.
LP2985ITLX-1.8
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LP2985AITLX-1.8/NOPB
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LP2985AITL-1.8
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LP2985AITLX-1.8
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Открыть даташит →LP2985AITLX-2.5
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LP2985AITLX-1.8 Максимальные параметры и электрические характеристики
| Manufacturer | Texas Instruments (originally National Semiconductor) |
| MPN | LP2985AITLX-1.8 |
| Product Type | LDO Linear Voltage Regulator (Fixed Output) |
| Nominal Output Voltage | 1.8 V |
| Output Voltage Accuracy | ±1.0% (A suffix) |
| Максимальный выходной ток | 150 mA |
| Диапазон входного напряжения | 2.2 V to 16 V |
| Dropout Voltage (typical) | 280 mV at 150 mA |
| Quiescent Current (active) | 850 µA typical |
| Quiescent Current (shutdown) | <1 µA |
| Выходной шум | 30 µVrms typical |
| Диапазон рабочих температур | -40 °C to +125 °C |
| Вывод разрешения | Yes (active-high, CMOS logic level) |
| Корпус | 5-ball micro SMD LBGA (TL suffix), seated height 1.22 mm |
| Terminal Pitch | 0.95 mm |
| Тип монтажа | Surface Mount |
| Terminal Count | 5 |
| Terminal Form | Ball (LBGA) |
| Статус RoHS | Compliant (NOPB suffix denotes lead-free) |
Конфигурация выводов LP2985AITLX-1.8
| Контакт A1 | VIN — Input supply |
| Контакт B1 | GND — Ground |
| Контакт C1 | VOUT — Regulated 1.8 V output |
| Контакт D1 | NC — Not connected (per datasheet) |
| Контакт E1 | EN/SHDN — Active-high enable / shutdown |
Типичное применение
LP2985AITLX-1.8 подходит для 7 применениеs: FPGA/ASIC 1.8V Core Auxiliary Rails, USB Peripheral Low-Voltage Rails, Battery-Powered Portable Devices, Post-Regulation After a Switching Converter, Industrial Sensor Signal Conditioning, IoT Edge Node Power Management, Point-of-Load Regulation for Noise-Sensitive Analog.
FPGA/ASIC 1.8V Core Auxiliary Rails
The LP2985AITLX-1.8 is well-suited for low-current 1.8 V auxiliary rails on FPGAs and ASICs where the design needs a clean, low-noise post-regulator after a switching converter. Its 150 mA current capability covers most 1.8 V auxiliary pins, while the ±1.0% 'A' tolerance keeps the rail within the FPGA's permissible supply window. The 30 µB rms noise floor prevents digital switching noise from coupling into sensitive analog blocks. Placed between a 3.3 V intermediate rail and the FPGA's 1.8 V supply pin with a 1 µF ceramic input and 2.2 µF ceramic output capacitor, the device adds no EMI but trades efficiency for simplicity. The micro SMD LBGA package enables placement directly under the BGA shadow.
Рекомендуется
USB Peripheral Low-Voltage Rails
USB peripherals frequently require a clean 1.8 V rail for serializer/deserializer chips and PHY interfaces. The LP2985AITLX-1.8 with its 16 V maximum input and 150 mA current is ideal for deriving 1.8 V from a 5 V USB VBUS rail. Its active-high enable pin supports USB suspend current requirements by dropping quiescent current below 1 µA when the bus is idle. The ±1.0% tolerance is sufficient for USB 2.0 PHY compliance, while the small LBGA package fits in the tight space of USB dongles and small peripherals. Compared to a switching regulator, the LP2985 adds no switching noise and avoids EMI compliance work in radiated-emission-sensitive products.
Рекомендуется
Battery-Powered Portable Devices
Portable, battery-powered devices benefit from the LP2985AITLX-1.8's 850 µA quiescent current and sub-1 µA shutdown current. The 16 V maximum input supports direct operation from a 2-cell or 3-cell lithium battery pack. The 'A' tolerance version delivers ±1.0% accuracy across the full industrial temperature window, critical for handheld equipment operating outdoors. The active-high enable pin allows the host MCU to gate the regulator during deep-sleep states, extending battery life. The micro SMD package reduces board area and enables ultra-thin products like wearables.
Рекомендуется
Post-Regulation After a Switching Converter
Many mixed-signal designs use a switching buck regulator for the main 3.3 V or 5 V rail, then a low-noise LDO like the LP2985AITLX-1.8 to clean up the 1.8 V analog or auxiliary supply. The LP2985's 30 µVrms output noise floor and high PSRR at low frequencies suppress ripple from the upstream switcher, making it ideal for noise-sensitive analog blocks. The 150 mA current limit matches most 1.8 V analog rail loads, and the LBGA package can be tucked under a shield can. With 1 µF input and 2.2 µF output ceramic capacitors, the regulator provides stable operation across the full load range.
Рекомендуется
Industrial Sensor Signal Conditioning
Industrial sensor signal-conditioning front-ends need a quiet 1.8 V rail to power op-amps, ADCs, and sensor interfaces. The LP2985AITLX-1.8 with its ±1.0% accuracy and 30 µVrms floor is well-matched to 16-/20-bit ADC reference and sensor-bias applications. The -40 °C to +125 °C operating range covers outdoor and industrial environments without derating. The wide 16 V input accepts 12 V and 24 V industrial bus rails after a primary regulator. The shutdown pin enables power gating in multi-channel sensor multiplexing designs.
Рекомендуется
IoT Edge Node Power Management
IoT edge nodes such as smart-home sensors and wireless modules need a low-standby-current 1.8 V rail for their microcontrollers and radios. The LP2985AITLX-1.8's sub-1 µA shutdown current is ideal for battery-powered IoT devices that spend most of their time in sleep mode. The active-high enable pin lets the host MCU gate the regulator during deep sleep, and the 850 µA quiescent current is acceptable for active operation. The micro SMD LBGA package supports ultra-compact IoT modules and wearables where board area is at a premium.
Рекомендуется
Point-of-Load Regulation for Noise-Sensitive Analog
Audio codecs, DACs, ADCs, and precision references often need a dedicated low-noise 1.8 V point-of-point rail. The LP2985AITLX-1.8's 30 µVrms noise floor and high line rejection cleanly derive the analog supply from a digital 3.3 V rail. The 1.0% output accuracy preserves reference voltage stability for precision ADCs. The small LBGA package can be placed adjacent to the analog IC to minimize trace-induced noise pickup. With 1 µF input and 2.2 µF output ceramic capacitors, the LDO provides stable regulation across the full load transient range.
Рекомендуется
Сводка рекомендуемых товаров
Справочные инженерные данные для LP2985AITLX-1.8 — сравнение, рекомендации по проектированию и информация о соответствии.
Руководство по выбору
Сравнение с аналогами
| Параметр | Этот товар | LP2985ITLX-1.8 | LP2985AITLX-1.8/NOPB | LP2985AITL-1.8 | LP2985AITLX-2.5 |
|---|---|---|---|---|---|
| Package | 5-ball micro SMD LBGA (TL) | 5-ball micro SMD LBGA (TL) - same | 5-ball micro SMD LBGA (TL) - same | 5-ball micro SMD LBGA (TL) - same | 5-ball micro SMD LBGA (TL) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Nominal Output Voltage | 1.8 V | 1.8 V | 1.8 V | 1.8 V | 2.5 V |
| Output Voltage Accuracy | ±1.0% (A grade) | ±2.0% (standard) | ±1.0% (A grade) | ±1.0% (A grade) | ±1.0% (A grade) |
| Maximum Output Current | 150 mA | 150 mA | 150 mA | 150 mA | 150 mA |
| Dropout Voltage (typ @150mA) | 280 mV | 280 mV | 280 mV | 280 mV | 280 mV |
| Quiescent Current (shutdown) | <1 µA | <1 µA | <1 µA | <1 µA | <1 µA |
| Lead-Free / RoHS | Standard (non-NOPB) | Standard | NOPB (lead-free) | Standard | Standard |
| Tape & Reel Packaging | Yes (X suffix) | Yes | Yes | No (no X suffix) | Yes |
Ключевые отличия
- Tightest tolerance in the LP2985 micro SMD family (против LP2985ITLX-1.8)
- Lead-free compliance with identical footprint (против LP2985AITLX-1.8/NOPB)
- Multiple output voltage options in same footprint (против LP2985AITLX-2.5)
Заметки по проектированию
Place the 1 µF ceramic input capacitor and the 2.2 µF ceramic output capacitor as close as possible to the LP2985AITLX-1.8 balls. Use X5R or X7R dielectric ceramic capacitors to maintain capacitance across the operating voltage. The 5-ball LBGA 'TL' package requires careful PCB pad design with non-solder-mask-defined (NSMD) pads and a recommended land pattern per TI's mechanical drawing. Estimated: trace length from VIN ball to input cap should not exceed 2 mm for stable operation.
The micro SMD LBGA 'TL' package has a small exposed backside for thermal conduction. At maximum 16 V input and 1.8 V output at 150 mA, the device dissipates (16 - 1.8) * 0.15 = 2.13 W of heat, requiring the PCB thermal pad to be soldered to a sufficient copper pour (at least 1 square inch) to keep the junction below 125 °C. Estimated: with 1 square inch of 1 oz copper on a 4-layer board, theta_JA is approximately 80 °C/W, giving a 170 °C rise which still requires derating at the upper input voltage range.
Do not confuse the LP2985AITLX-1.8 (5-ball ball-TLBGA) with the LP2985AIM5-1.8 (5-pin LSSOT-23) — they share the same die but the package dimensions and footprints are completely different. According to TI's part-number decoder, the 'TL' suffix denotes the ball-grid LBGA micro SMD package, not the SOT-23. PCB designers must verify the package code in the datasheet mechanical section before laying out the footprint.
Keep the LP2985AITLX-1.8 input and output traces short and wide to minimize parasitic inductance that could cause instability with ceramic capacitors. The enable pin (ball E1) should be tied to VIN through a 100 kΩ resistor if not driven by an MCU GPIO. Ground the unused ball (D1) or leave it floating per datasheet. Estimated: PCB keepout under the LBGA should be free of vias to maintain package solder-joint reliability.
Информация о соответствии
Lead-free version available as LP2985AITLX-1.8/NOPB suffix. Not AEC-Q100 qualified for automotive; for automotive-grade alternatives, TI recommends TPS7A2401 family. Halogen-free per TI material declaration.
