MC34129DR2 - Current Mode Switching Regulator for Telecom | NXP
部品番号: MC34129DR2 ✗ 生産終了| 数量 | 単価 | 小計 |
|---|---|---|
| 1 | $1.95 | $1.95 |
| 10 | $1.72 | $17.20 |
| 100 | $1.48 | $148.00 |
| 500 | $1.25 | $625.00 |
| 1,000 | $1.05 | $1,050.00 |
MC34129DR2 概要
A current-mode switching regulator is a type of DC-DC converter that uses the peak inductor current as the inner control loop rather than output voltage alone. The MC34129 belongs to the SMPS (Switched-Mode Power Supply) controller family, which sits within the broader hierarchy of power management ICs (PMICs) used to derive stable rails from telecom battery feeds. Current-mode control provides inherent cycle-by-cycle current limiting, simplified loop compensation, and good line-transient response, making it well suited to non-isolated point-of-load converters in 24 V to 48 V backplane environments.
Key features include an internal fault timer with automatic restart for overload recovery, duty-cycle clamp, and an on-chip start-up circuit. The 14-SOIC surface-mount package supports automated assembly, and the part is qualified over the 0 °C to 70 °C commercial operating range. Its low quiescent current of 2.5 mA and wide 4 V to 12 V input range target battery-backed telecom rails where efficiency and restart behavior after a short circuit are critical.
In typical application the device is wired as a step-down (buck) converter with an external MOSFET switch, inductor, and flyback Schottky diode. The current sense is taken from a low-side resistor in series with the inductor, and a single feedback resistor divider programs the output. The fault timer automatically initiates a soft restart after sustained overload, removing the need for an external watchdog.
Typical applications include digital telephone subscriber line interface circuits (SLICs), central-office line cards, ISDN terminal adapters, and other low-power telecom points-of-load. The wide supply range also supports industrial 12 V bus systems. When designing with this part, place the current-sense resistor within 1 cm of the sense pin and keep the high-current switching loop area to a minimum to limit conducted EMI on the telecom line.
ドロップイン代替品: MC34129DR2 — 同一パッケージでピン互換。PCBの作り直しが必要な異なるパッケージの部品は除外されています。
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MC33129DR2
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MC34129D
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MC33129D
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MC34129DR2 最大定格＆電気的特性
| Part Number | MC34129DR2 |
| Manufacturer | NXP Semiconductors |
| Product Type | Current-Mode Switching Regulator (SMPS Controller) |
| Application Category | Telecommunications PMIC |
| トポロジー | Current-mode PWM step-down controller |
| Supply Voltage Range | 4 V to 12 V |
| Operating Supply Current | 2.5 mA (typical) |
| 動作温度範囲 | 0 °C to 70 °C (commercial) |
| パッケージ / ケース | 14-SOIC (0.154 inch / 3.90 mm width) |
| 実装タイプ | Surface Mount (SMD/SMT) |
| Packaging | Cut Tape (CT) - Tape & Reel |
| ピン数 | 14 |
| Internal Fault Timer | Yes (automatic restart on overload) |
| ライフサイクル状態 | Obsolete (EOL) |
MC34129DR2 ピン構成
| ピン 1 | RT/CT — Oscillator timing resistor/capacitor node |
| ピン 2 | VREF — Internal 5 V reference output |
| ピン 3 | VFB — Voltage feedback / error amplifier inverting input |
| ピン 4 | COMP — Error amplifier output / PWM comparator input |
| ピン 5 | CS — Current sense input |
| ピン 6 | GND — Ground |
| ピン 7 | DRV — Gate driver output to external MOSFET |
| ピン 8 | VCC — Supply voltage input (4 V to 12 V) |
| ピン 9 | Vstart — Start-up voltage input |
| ピン 10 | SS — Soft-start programming pin |
| ピン 11 | FAULT — Fault timer / auto-restart capacitor |
| ピン 12 | UVLO — Undervoltage lockout programming |
| ピン 13 | NC — Not connected (per datasheet) |
| ピン 14 | NC — Not connected (per datasheet) |
主な用途
MC34129DR2 の用途: 6 件s: Digital Telephone SLIC Power Supply, Central Office Line Card DC-DC Converter, ISDN Terminal Adapter Power Rail, PBX System Point-of-Load Regulator, VoIP Gateway Auxiliary Supply, Industrial 12 V Bus Point-of-Load.
Digital Telephone SLIC Power Supply
The MC34129DR2 fits digital telephone SLIC (Subscriber Line Interface Circuit) power supplies because its 4 V to 12 V input range matches the post-bridge-rectifier telecom battery rail and its 2.5 mA quiescent current keeps standby draw minimal on line cards. The current-mode control provides cycle-by-cycle current limiting, which protects the SLIC from secondary shorts during line faults. Placed between the bulk hold-up capacitor and the SLIC AVDD rail with an external buck switch and current-sense resistor, it delivers a clean, regulated supply. Compared with a linear regulator, the switching topology avoids the heat dissipation problem at high line-to-load voltage drops typical of 48 V telecom rails.
おすすめ
Central Office Line Card DC-DC Converter
The MC34129DR2 suits central-office line-card DC-DC converters because its current-mode control simplifies loop compensation across multiple paralleled point-of-load rails. The internal fault timer with automatic restart eliminates the need for an external watchdog after overload events, a common fault in multi-card shelves where inrush transients can falsely trigger protection. Operating from 4 V to 12 V, the device can be fed from the shelf's intermediate bus after a primary front-end converter. The SOIC-14 footprint allows dense placement on line-card daughter boards where board real estate is at a premium.
おすすめ
ISDN Terminal Adapter Power Rail
The MC34129DR2 fits ISDN terminal adapter power rails because its low quiescent current (2.5 mA typical) supports energy-conscious standby modes mandated by telecom eco-regulations. The 4 V to 12 V supply range aligns with adapter wall-cube outputs, eliminating intermediate regulation stages. The internal automatic-restart fault timer handles short-circuit conditions gracefully, which is critical for unattended customer-premises equipment. Compared with a discrete switching controller, the integrated fault timer reduces BOM count and PCB area.
おすすめ
PBX System Point-of-Load Regulator
The MC34129DR2 fits PBX (Private Branch Exchange) system point-of-load regulators because its current-mode architecture rejects input-voltage variations on the shared 12 V backplane that supplies many PoL rails simultaneously. The 2.5 mA quiescent current is acceptable for always-on PBX shelves where standby power is a design target. The internal fault timer with auto-restart recovers gracefully from momentary overloads caused by peripheral cards being hot-swapped. The SOIC-14 package enables dense placement on PBX backplane cards.
おすすめ
VoIP Gateway Auxiliary Supply
The MC34129DR2 fits VoIP gateway auxiliary supplies because its 4 V to 12 V input range accepts the gateway's internal bus directly, and its current-mode control provides fast line-transient response when the gateway's main processor changes load current rapidly between idle and active states. The low 2.5 mA quiescent current preserves standby power budget. The internal fault timer recovers automatically from overloads caused by peripheral USB or Ethernet ports drawing inrush current.
おすすめ
Industrial 12 V Bus Point-of-Load
The MC34129DR2 can be adapted to industrial 12 V bus point-of-load converters where its 4 V to 12 V input window covers the regulated industrial bus rail. Its current-mode control tolerates the wide load-transient behavior of motor-control and PLC I/O subsystems on the same backplane. However, for new industrial designs the MC33129DR2 variant is preferred for its -40 °C to 85 °C industrial temperature range, while the MC34129DR2 remains appropriate for legacy industrial designs already in production. The SOIC-14 footprint enables standard SMT assembly.
おすすめ
おすすめ製品の概要
エンジニアリング参考データ: MC34129DR2 — 比較、設計ガイダンス、コンプライアンス情報。
選定ガイド
代替品との比較
| パラメータ | この製品 | MC33129DR2 | MC34129D | MC33129D |
|---|---|---|---|---|
| Package | 14-SOIC | 14-SOIC - same | 14-SOIC - same | 14-SOIC - same |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Supply Voltage Range | 4 V to 12 V | 4 V to 12 V | 4 V to 12 V | 4 V to 12 V |
| Quiescent Supply Current | 2.5 mA | 2.5 mA | 2.5 mA | 2.5 mA |
| Operating Temperature | 0 °C to 70 °C (commercial) | -40 °C to 85 °C (industrial) | 0 °C to 70 °C (commercial) | -40 °C to 85 °C (industrial) |
| Internal Fault Timer | Yes | Yes | Yes | Yes |
| Packaging Format | Tape & Reel (Cut Tape) | Tape & Reel (Cut Tape) | Tube | Tube |
| Lifecycle Status | Obsolete (EOL) | Obsolete (EOL) | Obsolete (EOL) | Obsolete (EOL) |
主な差別化要因
- Same-family industrial-temperature drop-in variant （vs MC33129DR2)
- Tube-packaged assembly variant （vs MC34129D)
- Industrial tube variant （vs MC33129D)
設計ノート
Place the current-sense resistor within 1 cm of the CS pin (pin 5) to minimize parasitic inductance that can corrupt the current-mode control loop. Keep the high-current switching loop area (VCC, MOSFET drain-source, inductor, and flyback diode return) tight and on a single PCB layer. Use a ground plane under the SOIC-14 package to provide thermal spreading and reduce EMI.
Do not exceed the maximum supply voltage of 12 V on VCC (pin 8). Voltages above 12 V can damage the internal start-up circuitry. For telecom applications fed directly from a 48 V battery, a front-end pre-regulator or dropper is required before the MC34129DR2. The internal fault timer capacitor on pin 11 sets the auto-restart interval; do not leave this pin floating.
Estimated: at VCC = 12 V, ambient = 25 °C, and low-side quiescent draw of 2.5 mA, the SOIC-14 dissipates roughly 30 mW internally - well below the SOIC-14 thermal limit. However, the external MOSFET switch driven by pin 7 (DRV) is the dominant thermal source in the converter and must be heatsinked per its own SOA. Keep the MC34129DR2 away from the MOSFET thermal footprint.
コンプライアンス情報
Compliance data not present in verified web data; mark as unknown. The part is designed for telecom (not automotive), so AEC-Q100 is not applicable. Refer to the NXP/Motorola datasheet for confirmed RoHS/lead-free declarations.
