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Texas Instruments UC2902N
- Part No.:
- UC2902N
- Manufacturer:
- Texas Instruments
- Category:
- Power Management - Specialized
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
UC2902N.pdf
- Description:
- IC LOAD SHARE CONTROLLER 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,045
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Product details
Overview
UC2902N from Texas Instruments is a load share controller IC designed to balance output current across paralleled DC-DC power supplies. It features an 8-pin PDIP package, 2.7–20 V operating range, 40× precision current sense amplifier gain, and differential share bus architecture for noise-immune current balancing in redundant or high-current power systems.
For engineers reviewing the UC2902N datasheet, UC2902N pinout, UC2902N application, or UC2902N equivalent, this device supports precise current sharing via remote voltage sensing, programmable share loop compensation, and undervoltage lockout-key considerations when designing fault-tolerant, scalable power architectures with mixed or mismatched converter ratings.
Technical Context
The UC2902N implements a master-slave load sharing topology where the highest-voltage supply auto-designates as master and drives the differential share bus (SHARE+ / SHARE−). Its internal current sense amplifier converts each converter's sensed current into a proportional bus voltage with 40× gain and ±2.5 mV input offset.
Current trimming of slave supplies is achieved by injecting controlled current into their remote sense lines via the ADJ/ADJR terminals, while the error amplifier (COMP) and share drive amplifier regulate loop stability using external RC compensation networks tied to the COMP pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating Voltage | 2.7 V to 20 V - powers directly from system rail without auxiliary bias supply |
| Current Sense Gain | −40 V/V - enables accurate current-to-voltage conversion with <±2.5 mV offset for ≤1% current matching |
| UVLO Threshold | 2.3 V to 2.7 V - prevents erratic startup during brownout; 100 mV hysteresis ensures clean turn-on |
| Share Bus Range | −0.3 V to 10 V - supports differential signaling with ground-referenced SHARE− for noise immunity |
| Supply Current | 4 mA to 10 mA - low quiescent draw minimizes overhead in multi-unit parallel configurations |
| Temp Range | −40°C to +85°C - qualified for industrial-grade embedded power systems |
| Slew Rate | 0.12–0.38 V/μs - sufficient for stable response to slow-load transients without oscillation |
Pinout & Package
UC2902N uses an 8-pin Plastic Dual In-line Package (PDIP), 0.300-inch width, with standard through-hole mounting and RoHS-compliant NIPDAU lead finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Signal & Power Ground | Reference node for all internal amplifiers and UVLO; must be low-impedance local return |
| SENSE (Pin 2) | Inverting Input | Connects to negative side of current sense resistor; sets gain path for current-to-bus conversion |
| ADJ (Pin 3) | Current Output | NPN collector output driving remote sense line; injects trim current to adjust slave output voltage |
| ADJR (Pin 4) | Current Reference | NPN emitter sets ADJ current magnitude; used with external resistor to limit trim current to 5–10 mA |
| COMP (Pin 5) | Error Amplifier I/O | Compensation node for share loop stability; connects external RC network to set crossover frequency |
| SHARE− (Pin 6) | Differential Reference | Common-mode reference for SHARE+; tied to system ground to reject ground noise |
| SHARE+ (Pin 7) | Bus Interface | Drives or senses differential share bus voltage; outputs up to 10 mA sink/source capability |
| VCC (Pin 8) | Power Supply | Primary supply input; powers all internal circuitry including amplifiers and UVLO comparator |
Key Features
| Feature | Design Value |
|---|---|
| Differential Share Bus | SHARE+/SHARE− interface rejects common-mode noise and accommodates ground potential differences between converters |
| Precision Current Sensing | 40× gain amplifier with ±0.5 mV typical offset enables ≤1% current matching across paralleled supplies |
| User-Programmable Compensation | COMP pin accepts external RC network to tailor share loop bandwidth and phase margin per converter dynamics |
| Auto-Master Selection | No external arbitration needed-the highest-output-voltage supply self-identifies as master and drives the share bus |
| Remote Sense Compatibility | ADJ/ADJR interface injects current into existing remote sense lines without modifying feedback divider networks |
Applications
| Telecom Rectifier Systems | Industrial Redundant PSUs |
|---|---|
Use Scenario: Multiple 48 V DC-DC modules supply base station RF power amplifiers with N+1 redundancy. IC Role / Device Role / Timing Role: UC2902N balances load current among rectifiers to prevent single-point overload and extend MTBF. Use Value: Enables use of off-the-shelf power modules without custom current-sharing circuitry, reducing BOM count and qualification effort. | Use Scenario: Factory automation PLCs require uninterrupted 24 V power using dual hot-swappable AC-DC supplies. IC Role / Device Role / Timing Role: UC2902N acts as analog current balancer, dynamically adjusting each supply's output voltage to match load demand. Use Value: Maintains balanced loading during hot-swap events and thermal drift, avoiding premature shutdown of weaker unit. |
| Medical Imaging Power Racks | Test Equipment Power Chassis |
Use Scenario: MRI gradient coil drivers draw >100 A from multiple synchronized switching supplies. IC Role / Device Role / Timing Role: UC2902N serves as analog load share controller, interfacing with each supply's remote sense terminals. Use Value: Achieves ±2% current matching across units despite ±5% tolerance in output voltage and temperature drift. | Use Scenario: Automated test systems use modular 12 V/30 A supplies in parallel to power DUTs under variable load profiles. IC Role / Device Role / Timing Role: UC2902N coordinates current distribution via differential share bus, independent of individual supply control loops. Use Value: Eliminates need for digital communication between supplies-reducing complexity and EMI susceptibility. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar load sharing applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UC3902N | Same architecture and pinout; rated for 0°C to +70°C commercial temp range vs. UC2902N's −40°C to +85°C | Not suitable for extended-temperature industrial or telecom deployments requiring full industrial grade operation | Select UC2902N when ambient operating temperature exceeds 70°C or cold-start reliability below 0°C is required. |
| LM5041MTX/NOPB | Integrated active current share controller with built-in gate driver; requires external MOSFETs and operates at higher switching frequencies | Targets synchronous buck-based current sharing with digital control interface; not drop-in compatible with UC2902N's analog remote-sense injection method | Choose LM5041MTX/NOPB only when redesigning for higher-efficiency, higher-frequency topologies with integrated PWM control. |
Compared with UC3902N, UC2902N provides broader temperature coverage essential for outdoor or uncontrolled-environment deployments; compared with LM5041MTX/NOPB, UC2902N offers simpler analog integration with legacy linear or flyback supplies lacking digital interfaces.
Availability
UC2902N is available at Aetrix Electronics and suitable for telecom rectifier systems, industrial redundant PSUs, medical imaging power racks, and test equipment power chassis requiring stable component supply across extended temperature ranges.
Supply support for UC2902N 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 over 50 years of innovation in high-reliability power control ICs.
The UC2902N belongs to TI's legacy load share controller product line, engineered specifically for analog current balancing in paralleled DC-DC power supplies without requiring digital communication or matched converter specifications.
FAQ
What is the primary function of the UC2902N in a power system?
The UC2902N is a dedicated analog load share controller that balances output current among paralleled DC-DC power supplies by regulating each unit's output voltage via remote sense line injection. It uses a differential share bus and precision current sensing to achieve tight current matching without digital coordination. The UC2902N enables reliable N+1 redundancy and thermal derating in industrial and telecom power systems.
How does the UC2902N determine which supply becomes the master in a parallel configuration?
The UC2902N implements automatic master selection: the power supply with the highest regulated output voltage self-identifies as the master and drives the SHARE+ bus. This eliminates need for external arbitration logic. The UC2902N on all other units then trims their output voltages downward to match the bus voltage minus 50 mV, ensuring proportional current sharing. This behavior is inherent to the UC2902N's internal error amplifier and share drive architecture.
Can the UC2902N be used with power supplies having different current ratings?
Yes, the UC2902N supports paralleling supplies with unequal current capabilities. By scaling the current sense resistor (RSENSE) value per unit, each supply contributes a percentage of its own maximum rating-for example, a 30 A and a 60 A supply can each deliver 50% of their capacity. This flexibility is enabled by the UC2902N's gain-stable current sense amplifier and adjustable ADJR current reference, allowing precise per-unit calibration without hardware changes to the UC2902N itself.
What is the role of the COMP pin on the UC2902N, and how is it configured?
COMP is the error amplifier output and compensation node for the share loop. An external RC network (typically 1 kΩ + 10 nF) is connected from COMP to GND to set loop bandwidth and phase margin. The UC2902N's transconductance of 4.5 mS and known external resistors allow designers to calculate crossover frequency using gM, RADJ, RG, and RSENSE. Proper COMP network design prevents oscillation and ensures stable current sharing during load transients.
Is the UC2902N pin-compatible with the UC3902N, and what are the key operational differences?
Yes, the UC2902N and UC3902N are fully pin-compatible 8-pin PDIP devices with identical electrical functionality and pin assignments. The sole difference is temperature rating: UC2902N is specified for −40°C to +85°C (industrial), while UC3902N is rated 0°C to +70°C (commercial). All timing, gain, and interface characteristics-including UVLO threshold, current sense accuracy, and share bus drive strength-are identical between the two. System designers should select UC2902N for extended-temperature deployments.
UC2902N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Applications:
- Load Share Controller
- Current - Supply:
- 4mA
- Voltage - Supply:
- 2.7V ~ 20V
- Operating Temperature:
- -40°C ~ 100°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
UC2902N FAQ
1.How can I place an order for UC2902N through Aetrix?
Please submit a Request for Quotation (RFQ) for UC2902N 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 UC2902N reliable?
The price and inventory of UC2902N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC2902N is usually 5 days.
3.What payment methods are accepted for UC2902N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC2902N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC2902N?
UC2902N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC2902N 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 UC2902N?
For technical support, including UC2902N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC2902N requirements.
6.How does Aetrix verify that UC2902N is sourced from the original manufacturer or authorized distributors?
All UC2902N 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 UC2902N meets industry standards.
7.What is the process for return or replacement of UC2902N?
All UC2902N units undergo pre-shipment inspection (PSI). If there is an issue with UC2902N, 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 UC2902N part is unused and in its original packaging.
Return procedure for UC2902N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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