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Texas Instruments UC2901Q
- Part No.:
- UC2901Q
- Manufacturer:
- Texas Instruments
- Category:
- Power Management - Specialized
- Package:
- 20-LCC (J-Lead)
- Datasheet:
-
UC2901Q.pdf
- Description:
- IC ISOLATED FB GENERATOR 20-PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,781
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Product details
Overview
UC2901Q from Texas Instruments is an isolated feedback generator IC designed for closed-loop regulation across voltage isolation boundaries in switch-mode power supplies. It implements amplitude modulation using an internal 150 kHz oscillator (±10 kHz over temperature), features a 1.5 V ±15 mV reference, integrated error amplifier with 60 dB CMRR and 100 dB PSRR, and delivers ±2.8 V driver output swing to drive RF transformers or optocouplers.
For engineers reviewing the UC2901Q datasheet, UC2901Q pinout, UC2901Q application, or UC2901Q equivalent, this device serves as a low-cost, transformer-coupled alternative to optical isolators in isolated DC-DC converters, offering programmable carrier frequency, loop status monitoring, and UVLO-enabled driver activation at 4.5 V.
Technical Context
The UC2901Q uses an internal amplitude-modulation architecture where the error amplifier's compensation terminal (Pin 12) modulates a high-frequency carrier (130–170 kHz) generated by an RC-controlled oscillator. The modulated signal drives two complementary emitter-follower outputs (DRIVERA/DRIVERB) with fixed 12 dB gain and ±2.8 V swing, enabling transformer-coupled feedback without optical components.
A dedicated STATUS output (Pin 13) asserts active-low when the error amplifier input differential falls within ±150 mV of the 1.5 V reference, indicating loop convergence. All drivers and STATUS are held inactive until VIN exceeds 4.5 V, satisfying UVLO requirements for reliable startup sequencing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 1.5 V ±15 mV over –40°C to +85°C - enables precise error thresholding for loop stability |
| Oscillator Frequency | 130–170 kHz (TJ = –40°C to +85°C) - sets transformer size and EMI profile for isolated feedback path |
| Error Amplifier Gain | 60 dB open-loop gain - supports stable compensation networks with standard RC networks on Pin 12 |
| Driver Output Swing | ±2.8 V - sufficient headroom to drive small RF transformers (e.g., Ferroxcube 3E2A) without external level-shifting |
| STATUS Input Window | ±150 mV around reference - provides unambiguous loop-in-regulation indication for system monitoring |
| Supply Range | 4.5 V to 40 V - accommodates wide-input industrial and telecom SMPS rails without auxiliary bias supply |
| UVLO Threshold | 4.5 V (typical) - ensures functional operation only after stable input rail establishment |
Pinout & Package
UC2901Q is housed in a 20-pin PLCC (FN package), surface-mount, leaded (Cu/Sn finish), moisture sensitivity level 2 (260°C peak reflow), with gull-wing leads and Pin 1 located in Quadrant 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (CR) | Oscillator timing capacitor connection | RC network sets carrier frequency; tie to VIN to disable internal oscillator and enable external clock sync |
| Pin 2 (CLK) | External clock input | Accepts TTL/CMOS clock up to 5 MHz; overrides internal oscillator when CR is tied high |
| Pin 11 (EA–) | Error amplifier inverting input | Receives feedback voltage from secondary-side divider; referenced to internal 1.5 V reference |
| Pin 12 (COMP) | Error amplifier compensation terminal | Output of EA; connects to feedback network (e.g., series R-C to EA–) for loop stability |
| Pin 13 (STATUS) | Active-low loop-status indicator | Asserts low when EA input differential is within ±150 mV of reference - signals regulation achieved |
| Pin 14 (DRIVERB) | Complementary driver output | Emitter-follower output; sinks ≥700 µA, sources ≥15 mA - drives transformer primary or optocoupler LED |
| Pin 15 (DRIVERA) | Primary driver output | Emitter-follower output, 180° out-of-phase with DRIVERB - enables push-pull transformer drive |
| Pin 20 (VIN) | Positive supply input | 4.5–40 V input; powers all internal blocks and enables drivers/STATUS only above UVLO threshold |
Key Features
| Feature | Design Value |
|---|---|
| Amplitude-modulated feedback generation | Eliminates optical coupler need by enabling transformer-coupled error signal transmission with <1% reference accuracy |
| Synchronizable carrier oscillator | Internal 130–170 kHz oscillator can be disabled and replaced with external clock - allows EMI alignment to switching frequency |
| Integrated loop status monitor | STATUS pin provides hardware-level confirmation of regulation window (±150 mV), simplifying system fault detection |
| UVLO-controlled driver enable | DRIVERA, DRIVERB, and STATUS remain tri-stated until VIN ≥ 4.5 V - prevents erratic startup behavior |
| Wide supply range & robust inputs | Operates from 4.5 V to 40 V; error amplifier inputs tolerate –0.5 V to +35 V - compatible with diverse secondary-side sensing schemes |
Applications
| Industrial AC-DC Power Supplies | Telecom Rectifiers |
|---|---|
Use Scenario: Regulating 48 V output from 230 VAC rectified bus in DIN-rail mounted power systems. IC Role / Device Role / Timing Role: Isolated feedback generator providing error signal across reinforced insulation barrier via RF transformer. Use Value: Replaces optocoupler with lower temperature drift, tighter reference tolerance (±15 mV), and no CTR degradation over time or temperature. |
Use Scenario: Maintaining tight voltage regulation in -48 V telecom rectifier modules with >3 kV isolation. IC Role / Device Role / Timing Role: Carrier-modulated feedback transmitter synchronized to 250 kHz PWM clock to minimize conducted EMI. Use Value: Enables deterministic EMI reduction through external clock sync while maintaining ±1.5% output regulation over line/load/temperature. |
| Medical Isolated DC-DC Converters | Programmable Lab Power Supplies |
Use Scenario: Secondary-side regulation in 5 V/3 A isolated converter for patient-connected diagnostic equipment. IC Role / Device Role / Timing Role: Isolation boundary interface generating amplitude-modulated error signal compliant with IEC 60601 creepage/clearance requirements. Use Value: Achieves 1.5 V reference accuracy ±15 mV over –40°C to +85°C - eliminates calibration drift seen with optocoupler-based solutions. |
Use Scenario: Precision output regulation in benchtop 0–30 V, 0–5 A linear/switching hybrid supplies requiring remote sense and isolation. IC Role / Device Role / Timing Role: Feedback error translator driving high-isolation capacitive coupling network instead of transformer. Use Value: Supports both transformer and capacitor coupling modes; STATUS output enables real-time regulation status reporting to microcontroller host. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar isolated feedback generator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UC3901Q | Commercial-grade (0°C to +70°C), same pinout and electrical specs except wider reference tolerance (±30 mV) and reduced oscillator stability (±40 kHz) | Targeted for non-industrial environments; lacks extended temperature support for harsh ambient conditions | Select UC3901Q only for cost-sensitive, non-extended-temp applications where ±30 mV reference drift is acceptable |
| LM5018-Q1 | Integrated flyback controller with internal MOSFET and optocoupler-compatible COMP pin - not a direct functional replacement but offers full control+feedback integration | Requires external optocoupler; lacks STATUS output and modulator sync capability | Choose LM5018-Q1 when consolidating controller and feedback into single chip is prioritized over transformer-based isolation simplicity |
Compared with UC3901Q, UC2901Q provides tighter thermal stability for reference and oscillator, making it suitable for industrial ambient ranges; versus LM5018-Q1, UC2901Q delivers dedicated, high-accuracy isolated feedback without integrating power-stage control - preserving design flexibility and noise isolation integrity.
Availability
UC2901Q is available at Aetrix Electronics and suitable for industrial AC-DC power supplies, telecom rectifiers, and medical isolated DC-DC converters requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant green packaging.
Supply support for UC2901Q 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 company delivering analog and embedded processing solutions, with leadership in power management, signal chain, and high-reliability ICs.
The UC2901Q belongs to TI's UCx901 isolated feedback generator product line, engineered specifically to replace optocouplers in isolated power supply feedback paths while improving accuracy, temperature stability, and EMI control.
FAQ
What is the operating temperature range for the UC2901Q?
The UC2901Q is rated for operation from –40°C to +85°C. This extended industrial temperature range distinguishes it from the commercial-grade UC3901Q (0°C to +70°C) and enables reliable use in demanding environments such as factory automation power systems and outdoor telecom infrastructure where ambient temperatures exceed standard commercial limits. The UC2901Q maintains full specification compliance-including 1.5 V reference accuracy and oscillator frequency stability-across this entire range.
Can the UC2901Q drive an optocoupler directly?
Yes, the UC2901Q can drive an optocoupler directly via its DRIVERA and DRIVERB outputs. Each output functions as an emitter-follower capable of sourcing up to 15 mA and sinking up to 700 µA. When used in DC mode (internal oscillator disabled and CLK pin held static), the device operates as a high-gain, 1% reference-based error amplifier with 12 dB gain from COMP to DRIVER outputs-ideal for linear optocoupler biasing. Its 4.5–40 V supply range and robust input voltage tolerance (–0.5 V to +35 V on EA inputs) further simplify interfacing with diverse optocoupler configurations.
How does the STATUS output of the UC2901Q function?
The STATUS output (Pin 13) of the UC2901Q is an active-low open-collector indicator that asserts logic low when the differential voltage at the error amplifier inputs (EA– and EA+) falls within ±150 mV of the internal 1.5 V reference. This condition corresponds to the regulated state of the power supply output. STATUS remains high-impedance until VIN exceeds the 4.5 V UVLO threshold, ensuring clean assertion only during valid operation. It provides immediate hardware-level feedback for microcontrollers or supervisory circuits without requiring ADC sampling or software interpretation.
What package type is used for the UC2901Q?
The UC2901Q is supplied in a 20-pin Plastic Leaded Chip Carrier (PLCC) package with FN drawing code, featuring gull-wing leads, Cu/Sn lead finish, and JEDEC MSL Level-2 moisture sensitivity (260°C peak reflow). Its compact 9.0 mm × 9.0 mm footprint and surface-mount construction support high-density PCB layouts in space-constrained power modules. The PLCC package also provides superior thermal performance compared to narrow SOIC variants, supporting continuous operation at full load under industrial ambient conditions.
Does the UC2901Q support synchronization to an external clock?
Yes, the UC2901Q supports full synchronization to an external clock via Pin 2 (CLK). When Pin 1 (CR) is tied to VIN, the internal oscillator is disabled, and the modulator accepts TTL/CMOS-compatible clock signals up to 5 MHz. This allows precise alignment of the carrier frequency with the main SMPS switching node-reducing beat frequencies and improving EMI performance. Unlike free-running oscillators, this sync capability ensures deterministic spectral placement of the feedback carrier, critical for meeting CISPR-22/32 conducted emissions limits in certified power designs.
UC2901Q Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-LCC (J-Lead)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Applications:
- Feedback Generator
- Current - Supply:
- 5mA
- Voltage - Supply:
- 4.5V ~ 40V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-PLCC (9x9)
UC2901Q FAQ
1.How can I place an order for UC2901Q through Aetrix?
Please submit a Request for Quotation (RFQ) for UC2901Q 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 UC2901Q reliable?
The price and inventory of UC2901Q are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC2901Q is usually 5 days.
3.What payment methods are accepted for UC2901Q?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC2901Q transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC2901Q?
UC2901Q orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC2901Q 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 UC2901Q?
For technical support, including UC2901Q datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC2901Q requirements.
6.How does Aetrix verify that UC2901Q is sourced from the original manufacturer or authorized distributors?
All UC2901Q 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 UC2901Q meets industry standards.
7.What is the process for return or replacement of UC2901Q?
All UC2901Q units undergo pre-shipment inspection (PSI). If there is an issue with UC2901Q, 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 UC2901Q part is unused and in its original packaging.
Return procedure for UC2901Q:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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