LM74502DDFR - 65V RPP & Load Switch Controller | TI
부품 번호: LM74502DDFR ✓ 활성| 수량 | 단가 | 합계 |
|---|---|---|
| 1 | $0.58 | $0.58 |
| 10 | $0.53 | $5.30 |
| 100 | $0.48 | $48.00 |
| 500 | $0.44 | $220.00 |
| 1,000 | $0.4 | $400.00 |
LM74502DDFR 개요
A reverse polarity protection controller governs external N-channel MOSFETs to block reversed or negative supply conditions while adding near-zero series resistance. Within the power-management hierarchy (RPP controller -> high-side controller -> power management IC), it replaces lossy series Schottky diodes, cutting conduction losses from hundreds of milliwatts to a few milliwatts. The back-to-back MOSFET arrangement also enables full load disconnect for safety-critical power paths.
Key features include the wide 3.2 V to 65 V industrial operating range that covers 12 V, 24 V, and 48 V DC buses, low quiescent current for always-on systems, integrated overvoltage protection (OVP) with programmable threshold, and an ultra-small TSOT-23-8 footprint. The controller drives common-source N-FET pairs, giving designers freedom to scale current rating through MOSFET selection rather than changing the controller.
Architecturally, the LM74502 uses an internal charge pump to enhance the external gate drivers above the source rail, keeping RDS(on) low during forward conduction and pulling the gate down quickly on reverse or overvoltage events. Precision comparators monitor input and output voltage to distinguish normal transients from fault conditions, asserting load disconnect only when required to minimize nuisance trips.
Typical applications include 12 V and 24 V industrial power supplies, 48 V telecom and PoE front ends, automotive-adjacent industrial loads, and battery-input systems where reverse battery insertion must not destroy downstream circuitry. DigiKey classifies the device under OR Controllers/Ideal Diodes, reflecting its diode-replacement role.
Design-wise, size the external FETs for both continuous current and the SOA during turn-off of a faulted supply, and keep gate-drive loops short. Verify that the OVP resistor divider tolerates the full transient rating of the bus.
This page adds distributor pricing, drop-in alternative cross-references, and practical design notes synthesized beyond the TI datasheet.
드롭인 대체품: LM74502DDFR — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:
LM74502HDDFR
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
LM74502DDFT
✅ 드롭인 ⚠️ 사양 미검증📋 참조 대체품 (카탈로그에 없음)
LM74610DDFR
✅ 드롭인 ⚠️ 사양 미검증📋 참조 대체품 (카탈로그에 없음)
LM74700DDFRQ1
✅ 드롭인 ⚠️ 사양 미검증📋 참조 대체품 (카탈로그에 없음)
LM74502DDFR 최대 정격 & 전기적 특성
| 기능 | High-side switch controller with reverse polarity protection (RPP) and overvoltage protection (OVP) |
| Supply Input Voltage Range | 3.2 V to 65 V |
| External MOSFET Type | N-Channel, back-to-back connected (1:1) |
| Configuration | Reverse polarity protection / load disconnect / load switch with OVP |
| 동작 온도 범위 | -40 C to +125 C |
| 패키지 | TSOT-23-8 (DDF), 8-pin surface mount |
| 실장 유형 | Surface Mount |
| Protection Features | Reverse polarity, overvoltage, load disconnect |
| RoHS 상태 | Compliant (per LCSC listing) |
| Product Classification (DigiKey) | OR Controllers, Ideal Diodes - N+1 ORing controller, N-channel, 1:1 |
LM74502DDFR tsot-23-8 (ddf), 8-pin surface mount 핀 구성 가이드
LM74502DDFR(tsot-23-8 (ddf), 8-pin surface mount 패키지)의 핀 구성입니다. 이 전력 소자는 게이트, 드레인, 소스 단자를 갖추고 있습니다. 비편향 패키지의 경우 정확한 핀 1 방향과 풋프린트 세부 정보는 제조사 데이터시트를 참조하십시오. 일반적인 응용 분야로는 전원 공급 장치 설계, 모터 구동, 부하 스위칭이 있습니다.
다음에 대한 상세 핀아웃 데이터 없음: LM74502DDFR.
다음을 참조하십시오: 데이터시트 전체 핀 구성은 다음을 참조하십시오.
일반적인 애플리케이션
LM74502DDFR 적합 용도: 6 애플리케이션s: Industrial 24 V Power Supply Front End, 48 V Telecom and PoE Front End, Battery-Input Equipment Reverse Protection, High-Side Load Switch with Overvoltage Protection, 12 V Distributed Power ORing, Base Station and Outdoor Cabinet Power.
Industrial 24 V Power Supply Front End
Industrial 24 V rails routinely see miswiring, load dumps, and reversed harnesses during maintenance. The LM74502DDFR operates from 3.2 V to 65 V, comfortably covering 24 V nominal systems with transient headroom, and drives back-to-back N-channel MOSFETs so reverse conditions are blocked with only milliohms of series resistance instead of a ~0.5 V Schottky diode drop. At a 5 A load, that diode drop wastes roughly 2.5 W, whereas an RDS(on) of 10 mOhm dissipates only about 0.25 W. Placed at the supply inlet with the OVP divider set above the expected bus, the controller disconnects the load on overvoltage faults, protecting downstream electronics and meeting industrial robustness expectations at minimal cost and board area.
추천
48 V Telecom and PoE Front End
48 V telecom and PoE infrastructures demand protection controllers that tolerate high transient voltages while remaining normally-on with very low standby drain. The LM74502DDFR's 65 V absolute input range covers 48 V nominal systems with substantial surge margin, and its low-IQ design suits always-on telecom shelves. In this role the controller enhances the external MOSFET gates via its internal drive stage, keeping forward drop near zero, and pulls gates low quickly on reverse or overvoltage events to isolate faults before they propagate into the PoE power bay. The compact TSOT-23-8 package minimizes front-end board area, and the ability to fully disconnect the load supports hot-service maintenance procedures on powered cabinets.
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Battery-Input Equipment Reverse Protection
Any battery-fed product faces the classic reversed-battery insertion fault, which destroys unprotected electronics within milliseconds. The LM74502DDFR senses input polarity and holds the back-to-back N-channel MOSFETs off on reverse conditions, blocking the fault without the constant power loss of a series blocking diode. Because the device operates from only 3.2 V, it stays functional even with deeply discharged single-cell or few-cell battery stacks, while the 65 V ceiling accommodates multi-cell lead-acid and 48 V lithium strings. Engineers should verify MOSFET VDS ratings against maximum charged-battery voltage including transients, and size gate-loop components per TI datasheet guidance so reverse-fault turn-off remains fast under high fault current.
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High-Side Load Switch with Overvoltage Protection
Beyond protection, the LM74502DDFR is explicitly configurable, per the TI datasheet, as a high-side load switch with overvoltage protection. This makes it suitable for switching field-installed loads such as heaters, valves, solenoids, and sensor clusters on 12 V to 48 V buses under MCU supervision. Because the current rating is set entirely by the external MOSFETs, one controller design scales from a few amps to tens of amps simply by changing the FET and copper area. The load-disconnect capability also provides a safety off-state for maintenance. Designers should add an output bleed resistor if slow FET turn-off leaves residual charge on large load capacitance, and respect MOSFET safe operating area during interruption of faulted loads.
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12 V Distributed Power ORing
DigiKey classifies the LM74502DDFR as an N+1 ORing controller (N-channel, 1:1), reflecting its suitability for paralleling redundant 12 V supplies. In an N+1 architecture, each supply feeds the common bus through a back-to-back MOSFET pair controlled by an LM74502; when one supply sags or fails, the controller blocks reverse current into the faulted unit and the healthy supplies carry the load without interruption. Compared with Schottky-diode ORing, the near-zero voltage drop saves roughly 0.4 V times load current per path - about 4 W saved at 10 A - reducing heatsinking and improving energy efficiency. The wide 3.2 V to 65 V input also permits reuse of one ORing design across 12 V, 24 V, and 48 V product variants.
추천
Base Station and Outdoor Cabinet Power
Outdoor telecom cabinets and 5G small-cell power entries face lightning-induced surges, -48 V reverse hookups, and -40 C to +85 C ambient swings. The LM74502DDFR's -40 C to +125 C rating, 65 V input ceiling, and RoHS-compliant TSOT-23-8 package fit these environments with margin. Configured as the first element after the surge suppressor, it provides reverse polarity blocking and overvoltage-triggered load disconnect, keeping expensive radio and baseband boards isolated from supply-side faults. Its low quiescent current matters because cabinet standby electronics draw continuous current even when radios are off. Pairing the controller with appropriately rated TVS devices and verifying MOSFET avalanche ratings yields a compact, robust front end for outside-plant deployment.
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추천 제품 요약
엔지니어링 참조 데이터: LM74502DDFR — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | LM74502HDDFR | LM74502DDFT | LM74610DDFR | LM74700DDFRQ1 |
|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | TSOT-23-8 (DDF) | TSOT-23-8 (DDF) - same | TSOT-23-8 (DDF) - same | TSOT-23-8 (DDF) - same | TSOT-23-8 (DDF) - same |
| Function | RPP + load disconnect + OVP | RPP + load disconnect + OVP | RPP + load disconnect + OVP | Reverse-battery ideal diode only | Ideal diode (reverse blocking) only |
| MOSFET Architecture | Back-to-back N-channel, 1:1 | Back-to-back N-channel | Back-to-back N-channel | Single N-channel, source-connected | Single N-channel ideal diode |
| Qualification Grade | Industrial | Automotive (H variant) | Industrial | Industrial | Automotive (Q1) |
주요 차별점
- Active overvoltage protection and full load disconnect (vs LM74610DDFR)
- Industrial pricing with automotive drop-in upgrade path (vs LM74502HDDFR)
- Wide 3.2 V to 65 V bus coverage (vs LM74700DDFRQ1)
설계 노트
The controller drives external back-to-back N-channel MOSFETs, so total front-end power loss is set by the FET choice. Estimated: at 5 A load with a 10 mOhm total series RDS(on) across both FETs, conduction loss is I^2 * R = 25 * 0.01 = 0.25 W - versus roughly 2.5 W for a 0.5 V Schottky diode. Select FETs with VDS rated at least 20-30% above the 65 V maximum bus to survive transients, and confirm gate-charge drive capability per the TI datasheet so turn-on is complete at the minimum 3.2 V supply.
Do not omit the input-to-output MOSFET common-source connection components and OVP divider described in the TI LM74502 datasheet typical applications. A frequent mistake is sizing the OVP threshold exactly at the nominal bus voltage - normal regulation ripple and cable drops then trigger nuisance load disconnects. Set the OVP threshold with margin above worst-case normal operation but below downstream component ratings. Also verify MOSFET safe operating area during interruption of a faulted, high-current supply, since the controller pulls the gates low while the FETs still carry fault current.
Keep the gate-drive loop from the controller's gate pins to the external MOSFET gates short and direct to minimize ringing during fast turn-off events. Place the sense components near the controller pins, and provide adequate copper pour on the MOSFET drain/source pads for the intended load current - estimated: 1 oz copper carries roughly 1 A per 0.3 mm of trace width with a 10 C rise, so a 5 A path needs at least 1.5 mm width plus vias. The TSOT-23-8 controller itself dissipates little power, so it needs no thermal relief.
규정 준수 정보
RoHS compliance stated on LCSC product page (C3236215). Industrial-grade part; the LM74502HDDFR variant addresses automotive qualification requirements. REACH, halogen-free, and conflict-minerals status not stated in fetched data.
