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NXP Semiconductors TDA3681ATH/N1C,512
- Part No.:
- TDA3681ATH/N1C,512
- Manufacturer:
- NXP Semiconductors
- Category:
- Power Management - Specialized
- Package:
- 20-SOIC (0.433", 11.00mm Width) Exposed Pad
- Datasheet:
-
TDA3681ATH/N1C,512.pdf
- Description:
- IC VOLT REG W/SW & IGNIT 20-HSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,760
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Product details
Overview
TDA3681ATH/N1C,512 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 operates across −40 °C to +85 °C ambient temperature.
For engineers reviewing the TDA3681ATH/N1C,512 datasheet, TDA3681ATH/N1C,512 pinout, TDA3681ATH/N1C,512 application, or TDA3681ATH/N1C,512 equivalent, key selection criteria include load dump protection up to 50 V, thermal shutdown at 150 °C, quiescent current of 110 µA in standby, and VP1/VP2 dual-supply architecture enabling dissipation reduction via external DC-DC.
Technical Context
The TDA3681ATH/N1C,512 integrates four independent linear regulators with foldback current limiting, a protected high-current power switch (3 A peak, 1.8 A continuous), and a Schmitt-trigger-based ignition buffer with push-pull output. Regulator 2 remains active during load dump and thermal shutdown to sustain microcontroller operation.
Its dual-supply inputs (VP1 and VP2) enable optimized thermal management: VP2 powers regulators 3 and 4 at reduced voltage (≥6.5 V), lowering power dissipation. The hold output (open-collector) activates on low VP1 (<9.7 V), load dump (>18 V), or overtemperature, 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) |
| Regulator Outputs | REG1: 8.5 V / 600 mA; REG2: 5.0 V / 300 mA; REG3: 5.0 V / 1400 mA; REG4: 3.3 V / 1 A |
| Power Switch | Drop-out ≤0.65 V @ 1 A; 3 A peak current; clamped at 16 V above 17 V VP1 |
| Quiescent Current | 110 µA typical in standby mode (all regulators and switch disabled, IGNIN low) |
| Thermal Protection | Shutdown at 150–170 °C junction; hold activation at same threshold |
| Reset & Hold | Adjustable reset delay (20–70 ms with 47 nF); hold output active LOW on low VP1, load dump, or overtemp |
| Ignition Interface | Schmitt-trigger IGNIN (2.2 V typ. rising threshold); push-pull IGNOUT (0.2 V LOW, 5.0 V HIGH) |
Pinout & Package
Package: HSOP20 (SOT418-3), plastic heatsink small outline package with 20 leads and low stand-off height; heat tab (pin 11) must be connected to ground in application.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| REG4 (1) | Regulator 4 output | 3.3 V / 1 A fixed output; foldback-protected; referenced to VP2 |
| IGNIN (2) | Ignition input | Schmitt-triggered control input (2.2 V typ. threshold); enables system wake-up detection |
| IGNOUT (3) | Ignition output | Push-pull buffer output; drives external logic or status indicator directly |
| RES (4) | Reset output | Active LOW open-collector signal; releases microcontroller after adjustable delay |
| CRES (5) | Reset delay capacitor | External capacitor (e.g., 47 nF) sets reset delay (20–70 ms) and power switch foldback timing |
| EN4 (6) | Enable for REG4 | Separate TTL-compatible control for regulator 4; independent of other regulators |
| EN1/3 (7) | Enable for REG1 & REG3 | Shared TTL-compatible control pin; simplifies sequencing of two 5 V rails |
| ENSW (8) | Enable for power switch | Dedicated TTL-compatible input; decouples switch control from regulator enables |
| HOLD (9) | Hold output | Open-collector active LOW fault signal; pulled LOW by low VP1, load dump, or overtemperature |
| GND (10) | Ground reference | Main signal and power return; connects to heat tab (pin 11) for thermal conduction |
| HEATTAB (11) | Thermal pad | Internally connected to GND; requires PCB copper pour for 2 K/W junction-to-case thermal resistance |
| REG2 (12) | Regulator 2 output | 5.0 V / 300 mA critical rail; remains active during load dump and thermal shutdown |
| BU (13) | Backup switch output | Provides backup path to REG2; supports capacitor hold-up during VP1 dropout |
| VP1 (14) | Primary supply input | Accepts battery voltage (9.5–18 V nominal); powers REG1, REG2, SW, and protections |
| n.c. (15) | No connection | Not internally bonded; must remain unconnected in PCB layout |
| SW (16) | Power switch output | High-side switch output; 3 A peak capability; clamped at 16 V when VP1 > 17 V |
| REG1 (17) | Regulator 1 output | 8.5 V / 600 mA main supply; most sensitive to low VP1 due to highest dropout requirement |
| n.c. (18) | No connection | Not internally bonded; must remain unconnected in PCB layout |
| REG3 (19) | Regulator 3 output | 5.0 V / 1400 mA high-current rail; powered from VP2 to reduce dissipation |
| VP2 (20) | Secondary supply input | Input for REG3 and REG4 (≥6.5 V); enables use of DC-DC converter to lower thermal load |
Key Features
| Feature | Design Value |
|---|---|
| Load dump protection | Withstands 50 V transients for ≤50 ms without regulator shutdown or latch-up |
| Dual-supply architecture | VP2 input allows REG3/REG4 to operate from lower voltage source, cutting die temperature rise by >30% |
| Microcontroller-safe reset | Adjustable delay prevents premature release; REG2 stays active during fault events to maintain MCU core supply |
| Low-noise regulation | Stable with small capacitors (220 nF ceramic + 100 µF electrolytic); noise as low as 55 µV RMS on REG4 |
| Integrated ignition interface | Self-contained Schmitt trigger + push-pull buffer eliminates need for external level-shifting or buffering circuitry |
| Fail-safe hold signaling | Single open-collector output reports three critical faults (low battery, overvoltage, overtemperature) with hysteresis to prevent chatter |
Applications
| Car Radio Power Management | Microcontroller-Based Infotainment |
|---|---|
Use Scenario: Central power unit for AM/FM/CD head units requiring multiple isolated rails and ignition-synchronized wake-up. IC Role / Device Role / Timing Role: Quad-regulator + switch IC supplies 8.5 V audio stage, dual 5 V logic/microcontroller rails, and 3.3 V digital interface; ignition buffer triggers system boot. Use Value: Eliminates discrete LDOs and external protection circuits; reduces BOM count by ≥7 components while meeting ISO 7637-2 pulse 5a requirements. | Use Scenario: Power subsystem for automotive infotainment with real-time OS, touchscreen, and Bluetooth connectivity. IC Role / Device Role / Timing Role: Primary power manager delivering stable 5.0 V to MCU core (REG2), 3.3 V to peripherals (REG4), and 8.5 V to analog audio (REG1); hold output halts firmware execution during brownout. Use Value: REG2's load-dump resilience ensures uninterrupted MCU operation during alternator surges; backup capacitor support enables graceful shutdown on battery disconnect. |
| Aftermarket Head Unit Design | Automotive Audio Amplifier Bias Supply |
Use Scenario: Compact replacement radio module needing robustness against reverse battery connection and jump-start voltages up to 30 V. IC Role / Device Role / Timing Role: Single-chip solution providing all regulated rails plus reverse-polarity-safe inputs (−18 V tolerant) and ignition-controlled power sequencing. Use Value: Reverse polarity protection avoids costly fuse+diode solutions; dual VP1/VP2 inputs simplify compliance with 12 V/24 V vehicle platforms. | Use Scenario: Bias supply for Class AB/D audio amplifier stages requiring low-noise, high-current 5 V and 8.5 V rails. IC Role / Device Role / Timing Role: REG3 (5 V / 1400 mA) powers amplifier logic and bias circuits; REG1 (8.5 V / 600 mA) supplies op-amp rails; low ripple (<75 mV line reg.) preserves SNR. Use Value: Integrated foldback current limiting prevents thermal runaway during speaker short-circuits; 60 dB SVRR suppresses alternator ripple from audio signal path. |
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 |
|---|---|---|---|
| TLF4941-2ES | Triple-output (5 V/3.3 V/2.5 V), no integrated power switch or ignition buffer; 40 V max VP, 125 °C junction rating | Lacks ignition interface and high-current switch; suited for simpler MCU-only systems without audio or actuator loads | Select when only three regulated rails needed and external switch/buffer acceptable; lower thermal margin than TDA3681ATH/N1C,512 |
| MAX16922ATP+ | Quad-output (5 V/3.3 V/2.85 V/1.8 V), integrated watchdog, 42 V max VP, 125 °C junction rating; no ignition buffer | Includes watchdog timer but omits ignition Schmitt trigger and dedicated power switch; targets ADAS camera modules | Choose for safety-critical vision systems requiring watchdog supervision; not drop-in for ignition-controlled radio designs |
Compared with TLF4941-2ES and MAX16922ATP+, the TDA3681ATH/N1C,512 uniquely combines ignition interface, high-current power switch, and load-dump-tolerant 50 V operation-enabling single-chip power management for full-featured car radios without supplemental protection ICs.
Availability
TDA3681ATH/N1C,512 is available at Aetrix Electronics and suitable for automotive infotainment, car radio power systems, and microcontroller-based vehicle electronics requiring stable component supply under harsh electrical conditions.
Supply support for TDA3681ATH/N1C,512 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 mixed-signal ICs.
The TDA3681ATH/N1C,512 belongs to NXP's automotive power management portfolio, engineered specifically for cost-sensitive, space-constrained car audio systems requiring integrated protection, multi-rail regulation, and ignition-aware power sequencing.
FAQ
What is the maximum allowable supply voltage for TDA3681ATH/N1C,512 during load dump conditions?
The TDA3681ATH/N1C,512 withstands load dump pulses up to 50 V for durations ≤50 ms with rise time ≥2.5 ms, per IEC 61000-4-5 and ISO 7637-2 Pulse 5a specifications. During such events, regulators 1, 3, and 4 shut down automatically, while regulator 2 remains active to sustain microcontroller operation. This behavior is intrinsic to the TDA3681ATH/N1C,512's internal protection architecture and requires no external circuitry.
How does the dual-supply architecture (VP1 and VP2) improve thermal performance of TDA3681ATH/N1C,512?
The TDA3681ATH/N1C,512 uses VP2 to power regulators 3 and 4, allowing connection to a lower-voltage source (≥6.5 V), such as a DC-DC converter. This reduces power dissipation on the die: for example, supplying REG3 (5 V / 1400 mA) from 14.4 V VP1 yields ~13.2 W loss, whereas using 7 V VP2 cuts loss to ~4.2 W-a >68% reduction. This directly lowers junction temperature and extends reliability in sealed automotive enclosures.
Can TDA3681ATH/N1C,512 support backup operation during battery disconnect?
Yes. The TDA3681ATH/N1C,512 includes a dedicated backup switch (BU pin) and supports an external backup capacitor on REG2. When VP1 drops to 0 V, the stored charge sustains REG2's 5.0 V output for tens of milliseconds-sufficient for a microcontroller to execute controlled shutdown or save state. The TDA3681ATH/N1C,512's internal backup control logic manages this transition without external intervention.
What is the function of the HOLD output on TDA3681ATH/N1C,512, and how is it used in system design?
The HOLD output on TDA3681ATH/N1C,512 is an open-collector, active LOW signal that asserts during low VP1 (<9.7 V), load dump (>18 V), or overtemperature (>150 °C). It must be pulled up externally (e.g., 10 kΩ to 5 V). System designers connect HOLD to MCU interrupt or reset inputs to initiate fault recovery routines. Its hysteresis prevents oscillation near thresholds, making it a robust system-level fault indicator within the TDA3681ATH/N1C,512.
Does TDA3681ATH/N1C,512 require external capacitors for stability, and what are the minimum values?
Yes. The TDA3681ATH/N1C,512 requires external output capacitors for loop stability: minimum 220 nF ceramic + 10 µF electrolytic per regulator output. For REG2, a 10 µF tantalum or larger electrolytic capacitor is recommended to ensure stability at −30 °C. Input supply lines VP1 and VP2 each need ≥220 nF ceramic capacitance close to the pins. These values are specified in the TDA3681ATH/N1C,512 test circuit (Fig.8) and stability guidelines.
TDA3681ATH/N1C,512 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 20-SOIC (0.433", 11.00mm Width) Exposed Pad
- Packaging:
- Tube
- 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/N1C,512 FAQ
1.How can I place an order for TDA3681ATH/N1C,512 through Aetrix?
Please submit a Request for Quotation (RFQ) for TDA3681ATH/N1C,512 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/N1C,512 reliable?
The price and inventory of TDA3681ATH/N1C,512 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TDA3681ATH/N1C,512 is usually 5 days.
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TDA3681ATH/N1C,512 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TDA3681ATH/N1C,512 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/N1C,512?
For technical support, including TDA3681ATH/N1C,512 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TDA3681ATH/N1C,512 requirements.
6.How does Aetrix verify that TDA3681ATH/N1C,512 is sourced from the original manufacturer or authorized distributors?
All TDA3681ATH/N1C,512 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/N1C,512 meets industry standards.
7.What is the process for return or replacement of TDA3681ATH/N1C,512?
All TDA3681ATH/N1C,512 units undergo pre-shipment inspection (PSI). If there is an issue with TDA3681ATH/N1C,512, 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/N1C,512 part is unused and in its original packaging.
Return procedure for TDA3681ATH/N1C,512:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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