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NXP Semiconductors TDA3681ATH/N1S,518
- Part No.:
- TDA3681ATH/N1S,518
- Manufacturer:
- NXP Semiconductors
- Category:
- Power Management - Specialized
- Package:
- 20-SOIC (0.433", 11.00mm Width) Exposed Pad
- Datasheet:
-
TDA3681ATH/N1S,518.pdf
- Description:
- IC REG MULTIPLE VOLTAGE 20HSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,069
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Product details
Overview
TDA3681ATH/N1S,518 from NXP Semiconductors (formerly Philips) is a quad-output automotive voltage regulator IC with integrated power switch and ignition buffer, designed for car radio systems. It delivers regulated 8.5 V (600 mA), 5.0 V (300 mA), 5.0 V (1400 mA), and 3.3 V (1 A) outputs, supports −18 V to +50 V supply range, and features load dump protection, thermal shutdown, and reverse polarity safety.
For engineers reviewing the TDA3681ATH/N1S,518 datasheet, TDA3681ATH/N1S,518 pinout, TDA3681ATH/N1S,518 application, or TDA3681ATH/N1S,518 equivalent, key selection criteria include its four independent regulator outputs with foldback current limiting, dual-supply architecture (VP1/VP2), ignition Schmitt trigger interface, hold/reset logic for microcontroller coordination, and HSOP20 package with heatsink tab for automotive thermal environments.
Technical Context
The TDA3681ATH/N1S,518 integrates four linear regulators-REG1 (8.5 V), REG2 (5.0 V, backup-capable), REG3 (5.0 V), and REG4 (3.3 V)-each with foldback current limiting and independent enable control. Regulators 3 and 4 accept a second supply (VP2 ≥6.5 V) to reduce power dissipation, while REG2 remains active during load dump and thermal shutdown to sustain microcontroller operation.
Its power switch (SW) provides 1.8 A continuous / 3 A peak current with delayed foldback protection tied to the reset delay capacitor (CRES), and its ignition buffer (IGNIN/IGNOUT) offers push-pull output with Schmitt-triggered input for robust vehicle battery state detection. The HOLD output (open-collector) activates low on low VP1 (<9.7 V), load dump (>18 V), or junction temperature >150 °C, providing system-level fault signaling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Range | −18 V to +50 V (reverse polarity safe to −18 V; load dump tolerant to 50 V for ≤50 ms) |
| Regulator Outputs | REG1: 8.5 V ±0.5 V @ 600 mA; REG2: 5.0 V ±0.25 V @ 300 mA (backup-capable); REG3: 5.0 V ±0.25 V @ 1400 mA; REG4: 3.3 V ±0.16 V @ 1 A |
| Power Switch | Vdrop = 0.45 V @ 1 A; 1.0 V @ 1.8 A; clamped at 16 V when VP1 ≥17 V; 3 A peak current capability |
| Quiescent Current | 110 µA typical in standby mode (all regulators and switch disabled, IGNIN low) |
| Thermal Protection | Junction shutdown at 150–170 °C; HOLD activation at same threshold; Rth(j-c) = 2 K/W (case-to-junction) |
| Ignition Interface | IGNIN Schmitt trigger: Vth(r) = 2.2 V, Vth(f) = 2.0 V; IGNOUT push-pull: VOH = 5.0 V, VOL = 0.2 V @ 0.8 mA |
| Reset & Hold | RESET (active LOW, push-pull): 240–900 µA source, 2 mA sink; HOLD (active LOW, open-collector): requires external pull-up |
Pinout & Package
Package: HSOP20 (SOT418-3), plastic heatsink small outline package with low stand-off height and exposed heat tab (pin 11) for thermal management in automotive under-dash environments.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (REG4) | Regulator 4 output | 3.3 V fixed output, rated for 1 A continuous, foldback protected |
| 2 (IGNIN) | Ignition input | Schmitt-triggered digital input detecting vehicle ignition state; hysteresis 0.2 V |
| 3 (IGNOUT) | Ignition output | Push-pull buffer driving external ignition indicator or control logic; active HIGH |
| 4 (RES) | Reset output | Active LOW push-pull signal releasing microcontroller after stable REG2 startup |
| 5 (CRES) | Reset delay capacitor | External capacitor setting RESET release delay (35 ms typ. with 47 nF) and power switch foldback timing |
| 6 (EN4) | Enable for REG4 | Logic HIGH enables REG4; independent of other regulators for flexible sequencing |
| 7 (EN1/3) | Enable for REG1 & REG3 | Single control pin enabling both 8.5 V and 5.0 V (1400 mA) regulators simultaneously |
| 8 (ENSW) | Enable for power switch | Logic HIGH activates SW output; protection delays foldback using CRES |
| 9 (HOLD) | Hold output | Open-collector output pulled LOW during low battery (<9.7 V), load dump, or overtemperature |
| 10 (GND) | Ground reference | Main signal and power ground; connects to PCB ground plane and heat tab |
| 12 (REG2) | Regulator 2 output | 5.0 V critical supply for microcontroller; operates during load dump and thermal shutdown |
| 13 (BU) | Backup switch output | Provides energy path from backup capacitor to REG2 during main supply loss |
| 14 (VP1) | Primary supply input | Main battery input (−18 V to +50 V); powers REG1, REG2, SW, and internal circuitry |
| 16 (SW) | Power switch output | Switched 12 V rail output; 1.8 A continuous, 3 A peak, with overvoltage clamp at 16 V |
| 17 (REG1) | Regulator 1 output | 8.5 V supply for analog front-end or display drivers; highest output voltage, most sensitive to low VP1 |
| 19 (REG3) | Regulator 3 output | 5.0 V high-current output (1400 mA); shares VP2 supply with REG4 to minimize dissipation |
| 20 (VP2) | Secondary supply input | Input for REG3 and REG4 only; ≥6.5 V recommended to reduce thermal load on IC |
Key Features
| Feature | Design Value |
|---|---|
| Quad independent regulators | Four fixed-output LDOs (8.5 V, 5.0 V, 5.0 V, 3.3 V) with individual enable inputs and foldback current limiting |
| Dual-supply architecture | VP2 input allows REG3/REG4 to be powered from a DC-DC converter, reducing total power dissipation by up to 40% |
| Microcontroller support logic | Integrated RESET (push-pull), HOLD (open-collector), and backup capacitor interface (BU) for controlled MCU boot and brownout recovery |
| Automotive-grade protection | Reverse polarity safe (−18 V), load dump tolerant (50 V/50 ms), thermal shutdown, and short-circuit safe outputs |
| Ignition state interface | Dedicated Schmitt-triggered IGNIN and push-pull IGNOUT enable reliable vehicle ignition detection without external components |
Applications
| Car Radio Power Management | Microcontroller-Based Infotainment |
|---|---|
Use Scenario: Central power supply for AM/FM/CD head units with analog audio stages, display drivers, and tuner modules. IC Role / Device Role / Timing Role: TDA3681ATH/N1S,518 provides four isolated, noise-optimized rails: 8.5 V for RF front-end, dual 5.0 V for digital logic and audio DAC, and 3.3 V for memory interfaces. Use Value: Eliminates need for discrete regulators and protection circuitry; maintains stable 5.0 V for MCU during 50 V load dump pulses per ISO 7637-2. | Use Scenario: Power subsystem for Linux-based automotive infotainment with ARM processor, DDR memory, and touch controller. IC Role / Device Role / Timing Role: TDA3681ATH/N1S,518 supplies 5.0 V (REG2) to the processor core with backup capacitor hold-up, 3.3 V (REG4) to I/O peripherals, and 8.5 V (REG1) to display backlight drivers. Use Value: HOLD signal halts system clocks before brownout; RESET ensures clean reboot after battery recovery; ignition buffer synchronizes boot sequence with vehicle start. |
| Aftermarket Navigation Unit | Telematics Control Unit (TCU) |
Use Scenario: Compact GPS/navigation module requiring robust power in varying vehicle electrical conditions. IC Role / Device Role / Timing Role: TDA3681ATH/N1S,518 delivers 5.0 V (REG3) to GPS baseband, 3.3 V (REG4) to cellular modem, and uses IGNOUT to drive status LED indicating ignition state. Use Value: Low-noise 5.0 V rail enables high-sensitivity GNSS reception; VP2-fed REG3/REG4 reduces thermal stress in sealed enclosures. | Use Scenario: Cellular-connected TCU handling OTA updates, diagnostics, and emergency call (eCall) functions. IC Role / Device Role / Timing Role: TDA3681ATH/N1S,518 powers 5.0 V (REG2) MCU with backup hold-up for graceful eCall initiation during battery disconnect, and 8.5 V (REG1) for CAN transceiver biasing. Use Value: Load dump immunity prevents false resets during alternator regulation faults; HOLD output triggers non-volatile log capture before shutdown. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar multiple-output automotive regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLF35584QVVS1 | Three LDOs (3.3 V/200 mA, 5.0 V/300 mA, 5.0 V/1 A) + watchdog + SPI interface; no ignition buffer or 8.5 V output | Requires external 8.5 V generation and discrete ignition sensing; better for ASIL-B systems needing diagnostics | Select if SPI-configurable supervision and functional safety compliance outweigh need for integrated ignition interface and 8.5 V rail |
| MAX16922ATP+T | Dual LDOs (5.0 V/300 mA, 3.3 V/250 mA) + boost controller + reset; no 8.5 V or 5.0 V/1400 mA outputs, no ignition buffer | Lacks high-current 5.0 V rail and vehicle-state interface; suited for compact ADAS cameras, not full infotainment | Select for space-constrained designs needing boost capability and lower quiescent current (35 µA), but add external circuits for ignition and 8.5 V |
Compared with TLF35584QVVS1 and MAX16922ATP+T, the TDA3681ATH/N1S,518 uniquely integrates an 8.5 V regulator, dual 5.0 V outputs (one high-current), ignition buffer, and HOLD/RESET logic in a single HSOP20 package-reducing BOM count and PCB area for cost-sensitive car radio platforms where functional safety certification is not required.
Availability
TDA3681ATH/N1S,518 is available at Aetrix Electronics and suitable for car radio power management, microcontroller-based infotainment, and telematics control units requiring stable component supply across extended temperature and harsh electrical environments.
Supply support for TDA3681ATH/N1S,518 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
NXP Semiconductors is a global semiconductor leader focused on automotive, industrial, and IoT applications, with deep expertise in high-reliability analog and power management ICs.
The TDA3681ATH/N1S,518 belongs to NXP's legacy automotive power management portfolio, specifically engineered for cost-effective, robust power delivery in car audio systems-emphasizing load dump resilience, low quiescent current, and integrated vehicle interface functions.
FAQ
What is the maximum continuous current capability of the power switch in TDA3681ATH/N1S,518?
The power switch in TDA3681ATH/N1S,518 delivers 1.8 A continuously when VP1 ≤18 V and VSW = 13.5 V. At VP1 ≥17 V, it clamps output at 16 V and limits current to 1.8 A. Peak current reaches 3 A for short durations before foldback activation, timed via the external CRES capacitor.
How does the TDA3681ATH/N1S,518 handle load dump events per ISO 7637-2?
TDA3681ATH/N1S,518 withstands 50 V load dump pulses for up to 50 ms on both VP1 and VP2 pins. During such events, regulators 1, 3, and 4 shut down automatically, while REG2 remains active to sustain microcontroller operation. The HOLD output goes LOW to signal fault condition, and the power switch disables above 18 V input.
Can the TDA3681ATH/N1S,518 operate with a single supply, or is VP2 mandatory?
VP2 is not mandatory for basic operation: TDA3681ATH/N1S,518 functions with VP1 alone for REG1, REG2, and SW. However, VP2 must be connected (≥6.5 V) to enable REG3 and REG4. Using VP2 from a DC-DC converter reduces power dissipation in those regulators by shifting dropout loss externally.
What is the purpose of the BU (backup switch) pin on the TDA3681ATH/N1S,518?
The BU pin on TDA3681ATH/N1S,518 provides a dedicated path from an external backup capacitor to REG2, allowing the 5.0 V microcontroller supply to remain active for tens to hundreds of milliseconds after main battery loss. This enables orderly MCU shutdown, data save, or eCall initiation without external diodes or switches.
Does the TDA3681ATH/N1S,518 require external capacitors for stability, and what values are recommended?
Yes, TDA3681ATH/N1S,518 requires external output capacitors for stability. Recommended values: 220 µF (ESR ≤0.15 Ω) for REG1/REG3/REG4; 10 µF tantalum or larger electrolytic for REG2. Minimum 220 nF ceramic capacitors are required on VP1 and VP2 supply lines per datasheet Figure 8.
TDA3681ATH/N1S,518 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 20-SOIC (0.433", 11.00mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Applications:
- Ignition Buffer, Regulator
- Current - Supply:
- 110µA
- Voltage - Supply:
- 9.5V ~ 18V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-HSOP
TDA3681ATH/N1S,518 FAQ
1.How can I place an order for TDA3681ATH/N1S,518 through Aetrix?
Please submit a Request for Quotation (RFQ) for TDA3681ATH/N1S,518 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for TDA3681ATH/N1S,518 reliable?
The price and inventory of TDA3681ATH/N1S,518 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TDA3681ATH/N1S,518 is usually 5 days.
3.What payment methods are accepted for TDA3681ATH/N1S,518?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TDA3681ATH/N1S,518 transactions.
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4.How is shipping managed for TDA3681ATH/N1S,518?
TDA3681ATH/N1S,518 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TDA3681ATH/N1S,518 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for TDA3681ATH/N1S,518?
For technical support, including TDA3681ATH/N1S,518 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TDA3681ATH/N1S,518 requirements.
6.How does Aetrix verify that TDA3681ATH/N1S,518 is sourced from the original manufacturer or authorized distributors?
All TDA3681ATH/N1S,518 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TDA3681ATH/N1S,518 meets industry standards.
7.What is the process for return or replacement of TDA3681ATH/N1S,518?
All TDA3681ATH/N1S,518 units undergo pre-shipment inspection (PSI). If there is an issue with TDA3681ATH/N1S,518, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The TDA3681ATH/N1S,518 part is unused and in its original packaging.
Return procedure for TDA3681ATH/N1S,518:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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