MIC29302BU - 3A Adjustable LDO Regulator, 26V VIN | Microchip
N.º da peça: MIC29302BU ✓ Ativo| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $4.32 | $4,32 |
| 10 | $3.85 | $38,50 |
| 100 | $3.18 | $318,00 |
| 500 | $2.46 | $1.230,00 |
| 1.000 | $2.1 | $2.100,00 |
MIC29302BU 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 very small. LDOs sit hierarchically under linear regulators, which in turn belong to the broader voltage regulator family within power management ICs. They are preferred over switching regulators in noise-sensitive applications because they introduce no switching ripple, at the cost of lower efficiency when VIN-VOUT is large.
Key features include ±2 % output accuracy, reverse-battery protection, current limiting, thermal shutdown, and an active-high TTL-compatible shutdown (EN) pin. The regulator uses Microchip's proprietary Super βeta PNP pass-element architecture, which keeps ground current low across the load range. The TO-263-5 package with the metal tab tied to the die enables continuous 3 A operation when soldered to adequate copper area.
Typical applications include point-of-load regulation after a switching converter, industrial 24 V-to-5 V/3.3 V rails, automotive body modules (non-safety), battery-powered equipment with reverse-polarity protection, and motor-driver auxiliary supplies. The reverse-battery feature is particularly valued in 12 V/24 V lead-acid systems where mis-wiring is a real risk.
When using this part, choose output capacitor ESR carefully (per datasheet curve) to avoid output instability, and lay out copper pour under the tab to keep junction temperature within limits - thermal resistance of approximately 2 C/W junction-to-case allows 15 W dissipation with a moderate heatsink.
Alternativas drop-in para MIC29302BU — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
MIC29303BU
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MIC29302BU TR
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MIC29150BU
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MIC29502WT
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MIC29300-5.0BU
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
LT1085CK
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MIC29302BU Classificações máximas e características elétricas
| Tipo de saída | Adjustable (positive) |
| Número de saídas | 1 |
| Corrente máxima de saída | 3 A |
| Input Voltage Range (VIN Min) | 2.25 V |
| Input Voltage Range (VIN Max) | 26 V |
| Rated Output Current | 3000 mA |
| Typical Dropout Voltage | 370 mV at 3 A |
| Output Voltage Accuracy | ±2 % |
| Adjustable VOUT | Yes |
| Shutdown / Enable Pin | Yes (active-high TTL) |
| Reverse Battery Protection | Yes |
| Limitação de corrente | Yes |
| Desligamento térmico | Yes |
| Power Good Signal | No |
| Bypass Pin | No |
| Encapsulamento | TO-263-5 (D2Pak, BU), 5 leads + tab |
| Tipo de montagem | Surface Mount |
| Faixa de temperatura de operação | -40°C to +125°C |
Configuração de pinos do MIC29302BU
| Pino 1 | EN — Enable / Shutdown input (active-high, TTL-compatible); tie to VIN if shutdown is not used |
| Pino 2 | VIN — Input supply voltage (2.25 V to 26 V); bypass with 10 µF low-ESR capacitor to GND |
| Pino 3 | GND — Ground return; tab is also internally connected to GND |
| Pino 4 | VOUT — Regulated output voltage (1.25 V to 25 V adjustable); bypass with 10 µF tantalum capacitor, ESR 0.025-0.5 Ω |
| Pino 5 | ADJ — Feedback input from output resistor divider; sets VOUT via VREF × (1 + R1/R2) |
Aplicações típicas
MIC29302BU é adequado para 7 aplicaçãos: Industrial 24V-to-5V Point-of-Load Regulation, Automotive Body Electronics and Aftermarket Accessories, Post-Switching-Converter Noise Filtering, Battery-Powered Equipment and Battery Chargers, Brushless Motor Driver Auxiliary Rails, FPGA and Microprocessor Core Supplies (Post-DC-DC), Telecom and Network Equipment 5 V Distribution.
Industrial 24V-to-5V Point-of-Load Regulation
The MIC29302BU is well-suited to industrial PLC and HMI power conditioning between a 24 VDC backplane rail and a 5 V logic rail. With VIN up to 26 V and 3 A continuous output, it can supply a substantial 5 V load (15 W) directly from 24 V bus power without a preceding switching stage. The 370 mV typical dropout at 3 A allows the regulator to hold regulation down to roughly 5.4 V input, accommodating the 24 V industrial rail's tolerance band. Compared to a switching converter this LDO adds no ripple on the 5 V rail - critical for analog I/O, encoder interfaces, and serial transceivers. PCB copper area beneath the TO-263-5 tab is required to keep Tj below 125 °C at 15 W dissipation; calculate: Tj = 25 °C + 19 W × θJA, where θJA is ~30 °C/W with adequate copper.
Recomendado
Automotive Body Electronics and Aftermarket Accessories
The MIC29302BU's 26 V absolute maximum VIN and built-in reverse-battery protection make it a strong fit for non-safety automotive body modules and aftermarket accessories powered from 12 V lead-acid systems. The reverse-battery protection survives brief mis-wiring events that are common during installation of amplifiers, lighting controllers, and alarm systems. The 3 A capability covers loads such as relay banks, LED driver stages, and small DC fans. Note this part is not AEC-Q100 qualified; for safety-critical ECUs the AEC-Q100-qualified MIC29150/3 siblings should be sourced instead. The 5-lead TO-263-5 form factor is well-suited to PCB-mount automotive enclosures with chassis ground. Reverse transient protection to -20 V can be enhanced with an external P-FET ideal-diode circuit at the input.
Recomendado
Post-Switching-Converter Noise Filtering
The MIC29302BU excels as a post-regulator sitting downstream of a switching DC-DC converter in noise-sensitive loads such as RF transceivers, audio codecs, and precision ADCs. By placing the MIC29302BU between the switcher's 5 V or 12 V intermediate rail and the noise-sensitive load, switching ripple (typically 20-50 mVpp at the converter output) is attenuated by the LDO's PSRR - typically 30 dB at 100 kHz for this family. The 3 A headroom supplies multiple downstream rails or high-current analog stages from a single post-LDO. The TO-263-5 footprint allows the post-LDO to be placed adjacent to the noise-sensitive load, keeping the high-impedance feedback loop short. Designers should pair a 10 µF tantalum with 1 µF X7R ceramic to extend PSRR beyond 1 MHz. This topology is common in wireless infrastructure and test equipment.
Recomendado
Battery-Powered Equipment and Battery Chargers
The MIC29302BU's 2.25 V minimum VIN supports multi-cell NiMH or Li-ion battery packs at full discharge, while the 26 V maximum covers 6-cell lead-acid battery stacks during equalization charging. The low ground current (typically 25-50 mA at full load) preserves battery life during standby. The active-high shutdown pin allows the host microcontroller to disable the regulator during deep sleep, dropping quiescent current to microamp levels. The reverse-battery protection makes this regulator robust for field-replaceable battery applications where the user may accidentally insert the pack reversed. For complete battery management, pair this regulator with a dedicated charger IC upstream and use the MIC29302BU strictly for post-regulation and load protection. A typical use is a portable instrument's digital supply.
Recomendado
Brushless Motor Driver Auxiliary Rails
In 3-phase brushless DC motor drivers, the MIC29302BU supplies auxiliary rails for gate drivers, Hall-effect sensors, and position encoder interfaces. The 3 A current is more than sufficient for these low-power peripherals while providing ample headroom for transient loads. The 26 V input tolerance matches 24 VDC industrial motor bus voltages, and the regulator's reverse-battery protection makes it suitable for portable tool applications where battery polarity errors are routine. The 5-lead TO-263-5 package allows direct PCB mounting adjacent to the motor-driver IC, minimizing trace length and EMI susceptibility. Designers should note that the regulator does not include a power-good signal; if PG is required for sequencing, an external window comparator can be added. The enable pin allows the MCU to cut power during braking or fault conditions.
Recomendado
FPGA and Microprocessor Core Supplies (Post-DC-DC)
The MIC29302BU is frequently used as a post-regulator after a buck converter supplying the core voltage of an FPGA or high-performance microprocessor. Modern FPGA core rails (1.0-1.8 V) draw tens of amps and require very tight tolerance (±3%) and low ripple - the MIC29302BU's ±2 % accuracy plus low-noise LDO behavior makes it suitable as a second-stage filter when the buck converter handles the bulk current conversion. Although 3 A is modest for an FPGA core, this part is well-suited to auxiliary rails like PLLs, transceivers, and I/O banks. The 26 V VIN-max makes it compatible with 12 V and 24 V intermediate bus architectures. PCB designers should run a Kelvin connection from the ADJ pin to the feedback divider to preserve accuracy.
Recomendado
Telecom and Network Equipment 5 V Distribution
Inside telecom shelves and small-cell base stations, the MIC29302BU distributes 5 V to line cards, fans, and alarm panels from a -48 V backplane (after an isolated intermediate bus converter reduces to 12 V). The 26 V VIN-max comfortably supports 12 V intermediate rails, and the 3 A current drives multiple small loads simultaneously. Reverse-battery protection is overkill in telecom but useful when the unit is bench-tested with lab supplies accidentally reversed. The 5-lead TO-263-5 package is widely accepted by NEBS-compliant hardware designers and produces acceptable thermal performance with standard 2 oz inner-layer copper pours. Designers targeting NEBS Level 3 should still add input TVS protection for surge and EMI compliance. The enable pin supports hot-swap insertion sequencing.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para MIC29302BU — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | MIC29303BU | MIC29150BU | MIC29502WT | MIC29300-5.0BU | LT1085CK |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Analog Devices |
| Package | TO-263-5 (D2Pak with tab) | TO-263-5 - same | TO-263-5 - same | TO-263-5 - same | TO-263-5 - same | TO-263-5 - same |
| Output Current | 3 A | 3 A | 1.5 A | 5 A | 3 A | 3 A |
| VIN Max | 26 V | 26 V | 26 V | 26 V | 26 V | 35 V |
| Output Type | Adjustable | Adjustable | Adjustable | Adjustable | Fixed 5.0 V | Adjustable |
| Output Accuracy | ±2 % | ±1 % | ±2 % | ±2 % | ±2 % | ±2 % |
| Dropout Voltage (typ at full load) | 370 mV at 3 A | 370 mV at 3 A | ~350 mV at 1.5 A | 370 mV at 5 A | 370 mV at 3 A | 1.3 V at 3 A |
| Shutdown Pin | Yes (active-high) | Yes | Yes (or 3-pin version) | Yes | Yes | No (3-pin only) |
| Reverse Battery Protection | Yes | Yes | Yes | Yes | Yes | No |
| 1k Pricing (USD) | $2.10 | $2.50 - $3.00 (est.) | $1.80 - $2.20 (est.) | $3.00 - $3.50 (est.) | $2.00 - $2.50 (est.) | $4.50 - $5.50 (est.) |
Principais diferenciais
- Active-high TTL shutdown pin on the same footprint (vs MIC29302WU (3-lead TO-263 without EN))
- Reverse-battery protection at no extra cost (vs LT1085CK (no reverse protection))
- Higher accuracy (±1%) upgrade path in same footprint (vs MIC29303BU)
- Better thermal headroom at 26 V VIN-max vs older 3 A LDO regulators (vs Legacy LM1085 / LM1084 families)
Notas de projeto
Estimated: At VIN = 24 V, VOUT = 5 V, IOUT = 3 A, power dissipation is roughly (24-5) V × 3 A = 57 W - far exceeding the TO-263-5 capability. Realistically, drop the input to 8 V (or use a switcher upstream) for high-current 5 V outputs. With VIN = 7 V, VOUT = 5 V, and 3 A the dissipation is 6 W, manageable with at least 1 sq inch of 2 oz copper plus airflow. The TO-263-5 tab-to-case thermal resistance is approximately 2 °C/W, and tab-to-ambient with adequate copper is 30-40 °C/W, so at 6 W the junction rise is ~180 °C - still too high without additional cooling. The typical rule of thumb is that the TO-263-5 family in production designs should not exceed 5 W of continuous dissipation without a dedicated heatsink.
Output capacitor selection is critical: a low-ESR ceramic output below 0.025 Ω ESR can cause regulator instability per the Microchip datasheet. Use a 10 µF tantalum or low-ESR aluminum capacitor with ESR in the 0.025-0.5 Ω range. If a ceramic is added for high-frequency bypass, keep it at 1 µF or smaller so the dominant pole is set by the tantalum. Another common pitfall: floating the EN pin (Pin 1) - if EN is left open the regulator will not start. Tie EN to VIN through a 10 kΩ resistor if the host MCU does not actively drive it. Finally, avoid routing the ADJ pin near switching noise - keep the feedback traces short and on the same layer as VOUT.
Layout recommendations for the MIC29302BU: (1) pour the top copper layer under the tab to maximize heatsinking - use multiple thermal vias to inner copper planes; (2) place input capacitor within 50 mil of the VIN pin to reduce input loop inductance; (3) place output capacitor within 100 mil of the VOUT pin with a short, wide trace to handle 3 A without significant IR drop; (4) place the ADJ feedback divider resistors directly at the ADJ pin with a ground reference that does not share high-current return paths; (5) for high-current designs, consider 2 oz copper on inner layers dedicated to VIN and VOUT. The exposed tab is electrically tied to GND internally - do not connect it to a different potential.
Quiescent current management: the MIC29302BU has ground current proportional to load, typically 25-50 mA at full 3 A and dropping to 5-10 mA at no load. When the EN pin is pulled low (inactive), the regulator enters shutdown with typical 10-100 µA consumption. To maximize battery life in portable applications, drive EN low during standby rather than relying on the regulator's idle current. Note the EN pin is TTL-compatible with a logic-low threshold of 0.8 V maximum and logic-high threshold of 2.0 V minimum, so it interfaces directly with 3.3 V and 5 V microcontrollers without level shifting. Adding a 100 kΩ pull-up on EN to VIN prevents floating in noisy environments.
Informações de conformidade
RoHS, REACH, lead-free, and halogen-free compliance status not present in retrieved web snippets; for production designs request the Microchip Material Declaration (MDDS) from the official product page or contact Microchip Customer Support for a signed compliance certificate. AEC-Q100 qualification not explicitly listed on the product page - for automotive safety-critical applications consult Microchip directly. The Microchip conflict-minerals statement is generally available from the corporate compliance portal.
