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Texas Instruments UC37131D
- Part No.:
- UC37131D
- Manufacturer:
- Texas Instruments
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
UC37131D.pdf
- Description:
- IC PWR SWITCH BIPOLAR 1:1 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,565
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Product details
Overview
UC37131D from Texas Instruments is a low-side smart power switch IC designed for driving resistive or inductive loads in industrial control and automotive subsystems. It delivers 300mA continuous output current, operates from 8V to 65V supply, features integrated 6V regulated reference (8mA), 2mA quiescent current, and built-in overload/short-circuit protection with programmable fault timing via external CDEL capacitor.
For engineers reviewing the UC37131D datasheet, UC37131D pinout, UC37131D application, or UC37131D equivalent, key selection considerations include its fixed 30% input comparator hysteresis, low-side-only configuration, SOIC-8 package, 1.2V typical saturation voltage at 25°C, and compatibility with 5V logic-level input control signals in high-noise environments.
Technical Context
The UC37131D implements a composite PNP-NPN output stage optimized for low-side switching, with internal 72V zener clamping between LS and GND to safely dissipate inductive kickback. Its fault logic uses a single CDEL capacitor to set both VCC power interruption recovery time and overcurrent response delay - charging/discharging between 1.0V and 4.9V thresholds with 4µA/94µA currents.
Input sensing is referenced to a 6V bandgap VREF; the IN pin triggers at 3.0V (½ VREF) with fixed 0.9V hysteresis. Current limiting is implemented via CSL-to-GND resistor (RCSL), where 150mV drop across RCSL initiates protection - e.g., 0.5Ω sets ~300mA threshold. LED pin provides open-collector fault indication.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 8V to 65V - supports wide-input industrial and automotive battery-supplied systems without external regulation. |
| Continuous Output Current | 300mA - sufficient for solenoids, relays, valves, and small motors in embedded control. |
| Saturation Voltage (VCE(sat)) | 1.2V typ @ 25°C, RLOAD = 100Ω - ensures <1.5W dissipation at full load, enabling compact thermal design. |
| Quiescent Current | 2.0–2.8mA - enables low-power standby operation in always-on subsystems. |
| VREF Output | 6.0V ±0.2V, 8mA max - powers external comparators or bias circuits without additional LDO. |
| Input Threshold & Hysteresis | 3.0V turn-on, 0.9V hysteresis (30%) - rejects noise on 5V logic control lines in electrically harsh environments. |
| CDEL Timing Range | Programmable tD(ON) = 9.5–13.5ms, tD(OFF) = 300–700µs - allows precise tuning of power-up delay and VCC glitch immunity. |
Pinout & Package
UC37131D is housed in an 8-pin SOIC (D package), pin-compatible with industry-standard SOIC-8 footprints. Thermal performance supports up to 1.5W dissipation under forced-air conditions.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (IN) | Logic Input | 5V-tolerant comparator input; 3.0V threshold with 30% hysteresis for noise-immune ON/OFF control. |
| 2 (GND) | Ground Reference | Common return for VREF, comparator, fault logic, and output driver - must be low-impedance. |
| 3 (VREF) | 6V Regulated Output | Stable 6V reference (±3.3%) sourcing up to 8mA; requires 1nF ceramic decoupling to GND. |
| 4 (CDEL) | Fault Timing Capacitor | Connects external capacitor to program VCC interruption recovery and overcurrent response timing. |
| 5 (QOUT) | Output Driver | Low-side NPN collector output; switches load between GND and VCC; includes 72V clamp diode. |
| 6 (VCC) | Power Supply | Main supply input (8–65V); requires local ceramic decoupling to suppress transients. |
| 7 (LED) | Open-Drain Fault Indicator | Active-low signal pulled low during fault (overcurrent, short, or VCC dropout); requires external pull-up. |
| 8 (CSL) | Current Sense Low-Side | Connects to GND via RCSL resistor; 150mV threshold sets current limit (e.g., 0.5Ω → ~300mA). |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 72V Zener Clamp | Enables safe inductive load switching without external flyback diodes - reduces BOM count and PCB area. |
| Single-Capacitor Fault Timing | CDEL pin programs both VCC interruption recovery and overcurrent response using one passive component. |
| Fixed 30% Input Hysteresis | Eliminates chatter on noisy control lines - no external components needed for robust 5V logic interfacing. |
| 6V/8mA On-Chip Reference | Powers external circuitry (e.g., sensor bias, comparator rails), reducing need for auxiliary regulators. |
| Programmable Overcurrent Limit | RCSL resistor sets precise trip point (250–400mA range), allowing optimization for specific load characteristics. |
Applications
| Industrial Motor Control | Automotive Body Electronics |
|---|---|
|
Use Scenario: Driving 12V/24V DC solenoid valves in PLC I/O modules with frequent on/off cycling and EMI exposure. IC Role / Device Role / Timing Role: Low-side power switch providing controlled current path to ground, with fast turn-off (<60µs fall time) and inductive energy clamping. Use Value: Eliminates external flyback diodes and reduces thermal stress via 1.2V saturation voltage - extends system lifetime in sealed enclosures. |
Use Scenario: Controlling seat heater elements or mirror defoggers in automotive cabin modules subject to load dump and cold cranking. IC Role / Device Role / Timing Role: Smart load switch with VCC dropout detection and automatic re-enable after recovery - prevents latch-up during battery transients. Use Value: CDEL-programmed 500µs VCC interruption tolerance avoids false shutdown during engine start, improving user experience. |
| Factory Automation Sensors | Medical Equipment Actuators |
|
Use Scenario: Powering 24V proximity sensors and photoelectric switches in dusty, vibration-prone manufacturing cells. IC Role / Device Role / Timing Role: Robust low-side driver with short-circuit protection and LED fault signaling for predictive maintenance alerts. Use Value: Open-collector LED output interfaces directly to PLC status inputs - enables real-time diagnostics without added logic. |
Use Scenario: Switching small linear actuators in portable diagnostic devices requiring low standby power and reliable fault handling. IC Role / Device Role / Timing Role: Energy-efficient load controller with 2.0mA quiescent current and programmable overcurrent recovery timing. Use Value: Prevents thermal runaway during actuator stall by entering low-duty-cycle pulsing mode - maintains safety compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-side smart switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UC37133D | High-side-only configuration; HS pin output; CSH current sense; same SOIC-8 package and timing architecture. | Requires load connected to GND instead of VCC - suitable for high-side grounding architectures (e.g., automotive chassis-grounded loads). | Select UC37133D only when load must be switched on the high side; not interchangeable with UC37131D due to opposite topology and pinout. |
| UC37132D | 16-pin SOIC; supports both high- and low-side modes; programmable 1–30% hysteresis via HYST pin; adds HS/LS dual outputs. | Offers greater flexibility in layout-constrained designs but requires more PCB area and external configuration resistors. | Choose UC37132D when future design reuse across topologies is required; avoid if strict pin count or cost constraints apply. |
Compared with UC37131D, UC37133D serves complementary high-side applications with identical fault timing and protection, while UC37132D provides multi-configuration capability at higher pin count and complexity - neither is pin-compatible, but all three share core protection logic and VREF architecture.
Availability
UC37131D is available at Aetrix Electronics and suitable for industrial motor control, automotive body electronics, factory automation sensors, and medical equipment actuators requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for UC37131D 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of heritage in industrial and automotive-grade IC design.
The UC37131D belongs to TI's UC371xx smart power switch family, engineered specifically for ruggedized load switching in electrically noisy environments where reliability, integrated protection, and minimal external components are critical.
FAQ
What is the maximum continuous output current rating for UC37131D?
The UC37131D is rated for 300mA continuous output current at 25°C ambient, with peak capability up to 700mA. This rating assumes proper PCB copper area for thermal dissipation and operation within the 0°C to +70°C temperature range specified for the UC37131D variant. Derating applies above 25°C per the device's thermal resistance specification.
Does UC37131D support high-side switching configurations?
No, UC37131D is strictly a low-side switch - its QOUT pin connects to the load's low-side terminal (i.e., load is between VCC and QOUT). High-side functionality is provided exclusively by UC37133D (high-side only) or UC37132D (dual-mode). Attempting high-side use with UC37131D will result in incorrect operation and potential damage.
How is overcurrent protection configured on UC37131D?
Overcurrent protection on UC37131D is set via an external resistor (RCSL) between the CSL pin and GND. A voltage drop of 150mV across RCSL triggers the fault circuit - so a 0.5Ω resistor sets a ~300mA threshold. The device then enters low-duty-cycle pulsing mode until the fault clears, as governed by the CDEL capacitor timing.
What is the purpose of the CDEL pin on UC37131D?
The CDEL pin on UC37131D hosts an external capacitor that controls two critical timing functions: (1) the delay before output enable after VCC power-up (tD(ON) ≈ 11ms typ), and (2) the minimum VCC interruption duration tolerated before fault activation (tD(OFF) ≈ 500µs typ). Both are derived from the same RC time constant.
Can UC37131D drive inductive loads without external protection components?
Yes - UC37131D integrates a 72V zener clamp between QOUT (LS) and GND, enabling direct switching of inductive loads like solenoids and relays without external flyback diodes. This clamp safely absorbs inductive kickback energy, reducing component count and board space while maintaining reliability under repetitive switching.
UC37131D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tube
- Product Status:
- Obsolete
- Switch Type:
- General Purpose
- Number of Outputs:
- 1
- Ratio - Input:Output:
- 1:1
- Output Configuration:
- Low Side
- Output Type:
- Bipolar
- Interface:
- On/Off
- Voltage - Load:
- 8V ~ 65V
- Voltage - Supply (Vcc/Vdd):
- Not Required
- Current - Output (Max):
- 300mA
- Rds On (Typ):
- -
- Input Type:
- Non-Inverting
- Features:
- -
- Fault Protection:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
UC37131D FAQ
1.How can I place an order for UC37131D through Aetrix?
Please submit a Request for Quotation (RFQ) for UC37131D 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 UC37131D reliable?
The price and inventory of UC37131D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC37131D is usually 5 days.
3.What payment methods are accepted for UC37131D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC37131D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC37131D?
UC37131D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC37131D 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 UC37131D?
For technical support, including UC37131D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC37131D requirements.
6.How does Aetrix verify that UC37131D is sourced from the original manufacturer or authorized distributors?
All UC37131D 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 UC37131D meets industry standards.
7.What is the process for return or replacement of UC37131D?
All UC37131D units undergo pre-shipment inspection (PSI). If there is an issue with UC37131D, 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 UC37131D part is unused and in its original packaging.
Return procedure for UC37131D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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