MIC29151T-3.3G - 1.5A LDO 3.3V Fixed TO-263-5 | Microchip
N.º da peça: MIC29151T-3.3G ✓ Ativo| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $2.1 | $2,10 |
| 10 | $1.89 | $18,90 |
| 100 | $1.68 | $168,00 |
| 500 | $1.49 | $745,00 |
| 1.000 | $1.32 | $1.320,00 |
MIC29151T-3.3G Visão geral
An LDO (Low-Dropout) linear regulator is a type of voltage regulator that maintains a stable output voltage even when the input-to-output voltage differential is small — typically a few hundred millivolts. LDOs sit hierarchically under linear regulators, then voltage regulators, then power management ICs, and ultimately semiconductors. Unlike switching regulators, LDOs add no switching noise to the output, making them ideal as post-regulators following switchers, or for directly powering noise-sensitive analog and digital loads.
Key features of the MIC29151T-3.3G include a typical dropout of 350 mV at 1.5A, ±1% initial output accuracy, very low quiescent current, an active-high enable pin for power sequencing, an error flag output (FLG) for monitoring VOUT regulation, and internal protection circuitry including thermal shutdown, current limiting, and reverse-battery protection. The TO-263-5 (DPAK-style) package provides a thermal pad that, with proper PCB copper area, allows sustained 1.5A operation without external heatsinking at moderate VIN-VOUT differentials.
The regulator uses a classical PNP-pass architecture with a bandgap reference, which is the engineering foundation for its low-dropout capability and fast transient response. On-chip protection blocks monitor junction temperature and output current independently, and a logic-level FLG pin signals when the output drops approximately 5% below nominal — useful for cascaded power-rail monitoring in multi-supply systems.
Typical applications for the MIC29151T-3.3G include 5V-to-3.3V post-regulation in industrial control boards, USB peripheral power, microcontroller and DSP core supplies, battery-backed 3.3V rails, networking line-card logic supplies, and FPGA/MCU auxiliary rails where switching noise from upstream converters must be cleaned up before reaching the load.
When designing with the MIC29151T-3.3G, ensure that the worst-case VIN-VOUT differential times load current stays within the package's SOAR limits; at 1.5A the dropout near 350 mV means VIN must be at least approximately 3.65V for regulation. Minimum ESR-stable output capacitance of 10 uF is required, and the enable pin must not be left floating — tie it high through a resistor for always-on operation.
This page consolidates the manufacturer datasheet, distributor stock and pricing, drop-in cross-brand equivalents, and practical design notes that supplement — and go beyond — the datasheet's nominal specification tables.
Alternativas drop-in para MIC29151T-3.3G — 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 MIC29151T-3.3G (mesmo formato e footprint) — diferindo em Input Voltage Range, Mounting Type, Output Type, Package.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
MIC29151-3.3WU
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MIC29151-3.3BT
✅ Drop-In ⚠️ Especificações não verificadas📋 Alternativa de referência (fora do catálogo)
MIC29152WT
✅ Drop-In ⚠️ Especificações não verificadas✓ Em estoque
$2.71 / unidade
Ver ficha técnica →TPS7A4533
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
NCP1117DT33
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MIC29151T-3.3G Classificações máximas e características elétricas
| Topologia | LDO (Low-Dropout) Linear Regulator |
| Tipo de saída | Fixed 3.3 V |
| Corrente máxima de saída | 1.5 A |
| Faixa de tensão de entrada | Up to 26 V |
| Tensão de dropout | 350 mV typical at 1.5 A |
| Output Voltage Tolerance | ±1% (initial) |
| Pino de habilitação | Yes (active-high) |
| Error Flag Output (FLG) | Yes (open-collector, asserts low on VOUT drop) |
| Desligamento térmico | Yes (internal) |
| Limitação de corrente | Yes (internal foldback) |
| Reverse Battery Protection | Yes |
| Encapsulamento | TO-263-5 (DPAK with 5 leads) |
| Tipo de montagem | Surface Mount |
| Temperatura de operação | -40 C to +125 C (junction) |
| Minimum Output Capacitor | 10 uF (low-ESR ceramic or tantalum) |
Configuração de pinos do MIC29151T-3.3G
| Pino 1 | EN — Enable input, active-high; tie to VIN through 10k pull-up for always-on operation |
| Pino 2 | VIN — Input supply voltage, typically 4.5V to 26V |
| Pino 3 | GND — Ground reference, internally connected to the metal tab |
| Pino 4 | VOUT — Regulated 3.3V output, up to 1.5A; place 10uF low-ESR capacitor as close as possible |
| Pino 5 | FLG — Error flag output, open-collector; asserts low when VOUT drops ~5% below nominal |
Aplicações típicas
MIC29151T-3.3G é adequado para 6 aplicaçãos: 5V-to-3.3V Post-Regulation for Microcontroller Core, Industrial PLC Logic Power Supply, USB Peripheral and Hub Power Rail, Networking Line-Card Logic Supply, Battery-Backed 3.3V Memory and RTC Rail, FPGA and DSP Auxiliary 3.3V Rail.
5V-to-3.3V Post-Regulation for Microcontroller Core
The MIC29151T-3.3G is well suited to clean up a 5V switching-rail output down to a clean 3.3V rail for microcontroller and DSP cores. With 1.5A continuous capability, it can supply the full MCU + external memory load while its 350 mV typical dropout allows operation from 5V ±5% inputs without dissipating excessive heat at low duty cycles. Place the regulator after a 5V buck converter with a 10uF low-ESR ceramic output cap; the lack of switching noise on the post-regulated rail eliminates clock-jitter on PLL-equipped MCUs and ADCs. The FLG pin can drive the MCU reset to enforce proper power-up sequencing. Estimated worst-case dissipation at VIN=5V, VOUT=3.3V, IOUT=1.5A is 2.55W, requiring about 1 sq inch of copper pour.
Recomendado
Industrial PLC Logic Power Supply
In 24V industrial PLC systems, the MIC29151T-3.3G provides a tightly regulated 3.3V rail from a 24V-to-5V intermediate bus for digital I/O logic, real-time clocks, and EEPROM-backed configuration memory. Its 1.5A rating supports multi-channel digital I/O banks plus a communication coprocessor, while its 26V absolute-maximum input withstands the typical 24V industrial rail with significant transient margin. The TO-263-5 package bolts down to the PLC chassis heatsink or main ground plane for sustained thermal performance at elevated ambient temperatures. Active-high EN enables sequenced start-up coordinated with a 5V upstream rail, and FLG signals PLC backplane controllers when the 3.3V rail is out of regulation. Internal reverse-battery and short-circuit protection further harden the design for industrial environments.
Recomendado
USB Peripheral and Hub Power Rail
USB peripherals, hubs, and downstream ports commonly require a regulated 3.3V rail derived from a 5V VBUS feed. The MIC29151T-3.3G drops the 5V USB rail to 3.3V at up to 1.5A with sub-1% accuracy, supporting multi-port hubs with several downstream devices plus on-board microcontrollers. The EN pin can be tied to USB VBUS through a 10k pull-up so the rail only powers up when VBUS is present, eliminating back-feed into a disconnected upstream host. The 350 mV dropout ensures full regulation at the minimum USB VBUS of 4.75V (5V -5%), and the FLG pin can drive a downstream device's reset to enforce a clean USB enumeration sequence. The TO-263-5 tab is ideal for PCB edge mounting and effective heat spreading in enclosed plastic hub enclosures.
Recomendado
Networking Line-Card Logic Supply
In networking line cards and routers, the MIC29151T-3.3G delivers a clean 3.3V rail for PHY transceivers, switch ASICs, and management controllers from a higher-voltage intermediate bus. The LDO's low output noise eliminates ripple coupling into sensitive Ethernet PHYs and clock-recovery PLLs, avoiding packet-error-rate degradation in Gigabit and 10G designs. At 1.5A continuous current, a single MIC29151T-3.3G can power a multi-port PHY plus its management CPU, simplifying BOM and saving board area compared with two parallel smaller LDOs. EN supports sequenced start-up coordinated with a 1.0V or 1.2V core rail generated from a separate buck converter, and FLG can be tied to the management CPU's interrupt for fault logging. The TO-263-5 footprint also provides robust thermal performance in tightly stacked line-card assemblies.
Recomendado
Battery-Backed 3.3V Memory and RTC Rail
Battery-backed systems need a 3.3V rail that survives brief main-power interruptions to preserve RTC registers and SRAM contents. The MIC29151T-3.3G's reverse-battery protection and current-limit make it suitable as the main 3.3V regulator with a small supercapacitor or lithium backup cell on its output, holding up the rail for tens of milliseconds during power transitions. The 350 mV dropout means the 3.3V rail remains in regulation down to about 3.65V on the input, giving the backup capacitor maximum hold-up time before the rail collapses. EN can be tied directly to the system enable signal so the rail powers down cleanly with the rest of the system. The FLG pin serves as a low-battery indicator that can wake the MCU before the rail is lost.
Recomendado
FPGA and DSP Auxiliary 3.3V Rail
FPGAs and DSPs often require multiple rails — typically 0.9V-1.2V core, 1.8V auxiliary, and 3.3V I/O — with the 3.3V rail providing I/O bank power to LVCMOS/LVTTL interfaces. The MIC29151T-3.3G supplies this 3.3V rail at up to 1.5A from a 5V intermediate bus, easily driving a full I/O bank plus peripheral level shifters. Its low quiescent current and high PSRR prevent noise from the upstream buck converter from reaching the FPGA's 3.3V I/O domain, which would otherwise corrupt LVDS reference levels and degrade signal integrity at multi-hundred-megahertz toggle rates. The EN pin supports a sequenced start-up order so the 3.3V rail comes up after the 1.8V rail, satisfying most FPGA power-sequencing requirements. With a TO-263-5 footprint and 1 sq inch of copper pour, the regulator sustains 1.5A at moderate ambient temperatures without external heatsinking.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para MIC29151T-3.3G — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | MIC29151-3.3WU | MIC29151-3.3BT | MIC29152WT | TPS7A4533 | NCP1117DT33 |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology (formerly Micrel) | Microchip Technology | Microchip Technology | Microchip Technology | Texas Instruments | onsemi |
| Package | TO-263-5 (DPAK with 5 leads) | TO-263-5 - same | TO-263-5 - same | TO-263-5 - same | TO-263-5 (KTW) - same | TO-252/TO-263 footprint compatible |
| Output Voltage | Fixed 3.3 V | Fixed 3.3 V | Fixed 3.3 V | Adjustable (1.25V min) | Fixed 3.3 V | Fixed 3.3 V |
| Maximum Output Current | 1.5 A | 1.5 A | 1.5 A | 1.5 A | 1.5 A | 1.0 A (-33%) |
| Enable Pin | Yes (active-high) | Yes (active-high) | Yes (active-high) | Yes (active-high) | Yes (active-high) | No |
| Error Flag / Power Good | FLG (open-collector error flag) | FLG | FLG | FLG | PG (Power Good, different logic) | None |
Principais diferenciais
- Integrated error flag (FLG) for rail monitoring (vs NCP1117DT33)
- 26V maximum input rating for industrial buses (vs NCP1117DT33)
- Same die in re-numbered MIC29151-3.3WU footprint (vs MIC29151T-3.3G itself)
Notas de projeto
Estimated: at VIN=5V, VOUT=3.3V, IOUT=1.5A, the MIC29151T-3.3G dissipates roughly 2.55 W. With the TO-263-5 package's theta_JA of approximately 30 C/W on a 1 oz copper pour of 1 square inch, the junction temperature rise is about 76 C, which keeps Tj below the 125 C limit at ambient temperatures up to 50 C. For higher VIN-VOUT differentials (e.g., 24 V input), reduce load current or add a small external heatsink. Input values used in the estimate: VIN=5 V, VOUT=3.3 V, IOUT=1.5 A, theta_JA=30 C/W, copper area=1 sq inch, 1 oz copper.
Solder the TO-263-5 metal tab to a continuous copper pour that connects to GND — this is both the ground reference and the primary thermal dissipation path. Place the 10 uF minimum output capacitor as close as possible to the VOUT and GND pins using short, wide traces to minimize parasitic inductance. A small 0.1 uF ceramic in parallel helps suppress high-frequency noise. For the FLG pin, route a 10 kohm pull-up to the 3.3 V rail or another logic supply rather than a noisy rail, and keep the trace short to avoid coupling.
Do not leave the EN pin floating — it must be driven high or pulled up to VIN via a 10 kohm resistor for proper regulator operation. Do not operate the regulator above the 26 V absolute maximum input rating, even during transient surges from a 24 V industrial bus; consider a TVS diode for additional protection. Do not assume the FLG pin is logic-level-drive — it is open-collector and requires a pull-up. Finally, do not substitute the MIC29151T-3.3G with a 1.0 A LDO such as the NCP1117DT33 if the design demands 1.5 A peak, since the part will enter current limit and VOUT will drop.
Informações de conformidade
RoHS and lead-free compliance indicated by the 'G' suffix in the part number per Microchip/Micrel ordering convention. AEC-Q100 automotive qualification is not applicable for this industrial-grade part; Microchip does not market an automotive-grade variant of the MIC29151.
