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Texas Instruments UC3909QTR
- Part No.:
- UC3909QTR
- Manufacturer:
- Texas Instruments
- Category:
- Battery Chargers
- Package:
- -
- Datasheet:
-
UC3909QTR.pdf
- Description:
- BATTERY CHARGE CONTROLLER
- Quantity:
- Payment:
- Shipping:
Inventory:930
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Product details
Overview
UC3909QTR from Texas Instruments is a switchmode lead-acid battery charger IC implementing average current mode control with integrated charge state logic, 1.5% voltage reference, –3.9mV/°C thermistor linearization, and 100mA open-collector output driver. It operates across 0°C to +70°C ambient, supports 7.5V–40V input supply, and delivers precise multi-stage charging (trickle, bulk, overcharge, float) for 12V/24V sealed or flooded lead-acid batteries in UPS, solar charge controllers, and telecom backup systems.
For engineers reviewing the UC3909QTR datasheet, UC3909QTR pinout, UC3909QTR application, or UC3909QTR equivalent, key selection criteria include its thermistor-compensated 2.3V reference accuracy, 220kHz oscillator frequency, dual open-collector STAT0/STAT1 state decode outputs, and RSET-programmable trickle current - all critical for temperature-aware battery management in industrial power systems.
Technical Context
The UC3909QTR implements a dual-loop control architecture: a voltage error amplifier (VEA) compares battery voltage against a thermistor-derived reference (2.3V ±0.0345V at 25°C), while a current error amplifier (CEA) compares sensed current against the VEA output to generate PWM duty cycle via an internal oscillator (220kHz typical). The charge state logic decodes four distinct stages using STAT0 and STAT1 open-collector outputs, with STATLV indicating float mode.
Its differential current sense amplifier provides 5× fixed gain with ±250mV common-mode range and 200kHz bandwidth, enabling accurate average current regulation from trickle to overcharge. Undervoltage lockout activates below 6.8V (7.8V typical turn-on) with 300mV hysteresis, ensuring stable startup only when VCC meets minimum operating threshold.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 220 kHz typical; sets switching speed and magnetic component sizing for high-efficiency DC-DC conversion. |
| Voltage Reference Accuracy | ±1.5% at 25°C; ensures precise battery voltage regulation thresholds across charge stages. |
| Thermistor Compensation | –3.9 mV/°C; dynamically adjusts float and overcharge voltages to maintain optimal battery health across temperature. |
| Current Sense Gain | 5 V/V fixed; enables direct scaling of shunt resistor voltage to PWM comparator input for robust average current control. |
| STAT0/STAT1 Output Sink | 10 mA max per pin; drives external LEDs or logic interfaces to indicate real-time charge state (trickle/bulk/overcharge/float). |
| UVLO Turn-on Threshold | 7.8 V typical with 300 mV hysteresis; prevents erratic operation during brownout or cold-start conditions. |
| Operating Ambient Range | 0°C to +70°C; defines validated performance envelope for commercial-grade industrial battery systems. |
Pinout & Package
UC3909QTR is housed in a 28-pin PLCC (FN) package with gull-wing leads, RoHS-compliant green finish, and JEDEC MSL Level-2-220°C-1 year moisture sensitivity rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND | Reference ground | Common return for internal references, thresholds, and output sink transistor; must be low-impedance connection. |
| OVCTAP | Overcharge taper current sense | Inputs scaled current sense signal to detect taper threshold and trigger transition from overcharge to float state. |
| OSC | Oscillator ramp node | Connects external CT capacitor to ground; generates 1–3V sawtooth ramp at 220kHz for PWM timing. |
| OUT | PWM driver output | Open-collector NPN capable of sinking 100mA continuous; drives external MOSFET gate or transformer primary. |
| R10 | Thermistor reference divider | Connects 10kΩ resistor to ground; establishes differential voltage proportional to thermistor temperature. |
| RSET | Oscillator and trickle current programming | Sets oscillator charge current (≈1.75/RSET) and trickle bias current (≈0.115/RSET) via external resistor to ground. |
| RTHM | Thermistor connection | Accepts 10kΩ NTC thermistor to ground; resistance variation modulates internal 2.3V reference for thermal compensation. |
| STAT0 / STAT1 | Charge state decode outputs | Open-collector outputs encoding four states: 00=trickle, 01=bulk, 10=overcharge, 11=float (per decode chart). |
| STATLV | Float state indicator | Open-collector output asserted high only during float charge; used for system-level float-mode signaling. |
| VA– | Voltage error amplifier inverting input | Receives scaled battery voltage; compared against thermistor-derived reference to regulate charge voltage. |
| VAO | Voltage error amplifier output | Clamped at 5V maximum; drives current error amplifier and serves as current command signal in bulk/overcharge. |
| VCC | Power supply input | 7.5–40V operating range; requires 1µF bypass capacitor; powers all internal circuitry including 5V logic reference. |
| VLOGIC | 5V precision reference output | 4.875–5.125V at 15V VCC; supplies stable reference for comparators and analog blocks; bypass with 0.1µF capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| Average current mode control | Enables stable, ripple-immune current regulation from trickle to overcharge without requiring slope compensation. |
| Four-state charge algorithm with decode bits | STAT0/STAT1 outputs provide unambiguous, externally readable indication of real-time charge stage for system monitoring. |
| Thermistor-linearized reference | –3.9mV/°C coefficient matches NTC characteristics, enabling automatic float voltage adjustment across –40°C to +70°C. |
| Resistor-programmable charge parameters | RSET sets both oscillator frequency and trickle current; R10/RTHM set thermal reference point - no trimming required. |
| Integrated undervoltage lockout | Prevents startup until VCC ≥7.8V, eliminating erratic behavior during low-input or soft-start conditions. |
Applications
| Uninterruptible Power Supply (UPS) | Solar Charge Controller |
|---|---|
Use Scenario: Maintaining standby battery bank during grid outage with automatic reconditioning cycles. IC Role / Device Role / Timing Role: Primary battery charge controller managing four-stage algorithm and thermally compensated voltage setpoints. Use Value: Extends battery life by preventing overvoltage at high temperatures and undercharging at low temperatures via –3.9mV/°C reference tracking. |
Use Scenario: Regulating charge from variable PV array output into 12V/24V lead-acid storage with daily cycling. IC Role / Device Role / Timing Role: Core analog controller executing trickle→bulk→overcharge→float transitions based on sensed voltage/current/temperature. Use Value: Enables full utilization of solar harvest through precise current-limited bulk charging and temperature-adapted float maintenance. |
| Telecom Backup System | Industrial Battery Maintenance Charger |
Use Scenario: Providing long-term float maintenance for central office battery strings with remote status reporting. IC Role / Device Role / Timing Role: Standalone charge manager generating STAT0/STAT1 state bits for SNMP or Modbus telemetry interface. Use Value: Delivers verified 5V logic-compatible status signals (0–10mA sink) for integration into legacy telecom monitoring infrastructure. |
Use Scenario: Automated periodic reconditioning of forklift or emergency lighting batteries in warehouse environments. IC Role / Device Role / Timing Role: Self-contained charger IC initiating trickle recovery on low-voltage detection and terminating at full float. Use Value: Eliminates manual intervention by autonomously detecting battery state-of-charge via CHGENB comparator and executing full algorithm. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switchmode lead-acid battery charger applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UC3909DWTR | SOIC-20 package (vs. PLCC-28); identical electrical specs, same 0°C to +70°C rating, but different pinout and thermal profile. | Lacks STATLV pin; uses different pin mapping for RTHM/R10/OSC; requires PCB redesign for drop-in replacement. | Select UC3909DWTR only when SOIC-20 footprint and lower profile are required, and board layout can accommodate revised pin assignments. |
| BQ24450 | Single-chip solution with integrated MOSFET drivers; lacks thermistor linearization circuit and external RSET programming for trickle current. | Designed for simpler constant-voltage/constant-current profiles; does not implement UC3909QTR's four-state decode or –3.9mV/°C compensation. | Choose BQ24450 for cost-sensitive, space-constrained designs where full thermal adaptation and state visibility are not required. |
Compared with UC3909QTR, UC3909DWTR offers identical functionality in a smaller SOIC package but requires layout changes due to incompatible pinout and missing STATLV, while BQ24450 simplifies design with integrated drivers but sacrifices programmable thermal compensation and explicit charge-state reporting.
Availability
UC3909QTR is available at Aetrix Electronics and suitable for uninterruptible power supplies, solar charge controllers, telecom backup systems, and industrial battery maintenance equipment requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for UC3909QTR 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 and embedded processing technologies, with decades of expertise in power management and battery solutions.
The UC3909QTR belongs to TI's dedicated battery charger IC product line, engineered specifically for high-accuracy, thermally adaptive lead-acid charging in industrial and telecom infrastructure applications.
FAQ
What is the operating temperature range for the UC3909QTR?
The UC3909QTR is specified for operation from 0°C to +70°C ambient temperature. This commercial-grade range aligns with its intended use in indoor industrial power systems such as UPS and telecom cabinets. Unlike the UC2909 variant (–40°C to +85°C), the UC3909QTR does not support extended industrial temperature operation, and derating or validation beyond +70°C is not guaranteed per datasheet specifications.
How does the UC3909QTR implement temperature compensation for battery charging?
The UC3909QTR uses a dedicated thermistor interface (RTHM and R10 pins) to generate a temperature-dependent reference voltage with a precise –3.9mV/°C coefficient. This linearized reference directly scales the voltage error amplifier's setpoint, automatically lowering float and overcharge voltages as temperature rises - preventing thermal runaway and extending battery service life. The UC3909QTR achieves this without external op-amps or digital calibration.
What are the key differences between UC3909QTR and UC3909DWTR?
The UC3909QTR is a 28-pin PLCC (FN) device with STATLV output and full pin compatibility within the Q-package family, while UC3909DWTR is a 20-pin SOIC (DW) variant lacking STATLV and featuring a completely different pinout. Both share identical electrical specifications and temperature rating (0°C to +70°C), but PCB layout, thermal dissipation, and mechanical mounting differ significantly - making them non-interchangeable without hardware revision.
Can the UC3909QTR be used for lithium-ion battery charging?
No, the UC3909QTR is explicitly designed for lead-acid chemistry and is not suitable for lithium-ion batteries. Its four-stage algorithm (trickle/bulk/overcharge/float), thermistor compensation slope (–3.9mV/°C), and voltage thresholds (e.g., 2.3V reference) match sealed/flooded lead-acid requirements. Lithium-ion needs constant-current/constant-voltage with tighter voltage tolerance (±0.5%), cell balancing, and safety cutoffs - none of which the UC3909QTR provides.
What external components are required to configure the UC3909QTR for a 24V lead-acid system?
To configure UC3909QTR for 24V operation, you need: (1) RSET (e.g., 11.5kΩ) to set oscillator frequency and trickle current, (2) RTHM (10kΩ NTC thermistor) and R10 (10kΩ) for thermal compensation, (3) CT capacitor (e.g., 330pF) on OSC pin, (4) current sense resistor RS calculated as 350mV/IBULK, and (5) voltage divider network (RG1/RG2) on VA– to scale battery voltage to match the 2.3V reference. No microcontroller or firmware is required.
UC3909QTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Battery Chemistry:
- -
- Number of Cells:
- -
- Current - Charging:
- -
- Programmable Features:
- -
- Fault Protection:
- -
- Charge Current - Max:
- -
- Battery Pack Voltage:
- -
- Voltage - Supply (Max):
- -
- Interface:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
UC3909QTR FAQ
1.How can I place an order for UC3909QTR through Aetrix?
Please submit a Request for Quotation (RFQ) for UC3909QTR 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 UC3909QTR reliable?
The price and inventory of UC3909QTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC3909QTR is usually 5 days.
3.What payment methods are accepted for UC3909QTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC3909QTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC3909QTR?
UC3909QTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC3909QTR 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 UC3909QTR?
For technical support, including UC3909QTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC3909QTR requirements.
6.How does Aetrix verify that UC3909QTR is sourced from the original manufacturer or authorized distributors?
All UC3909QTR 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 UC3909QTR meets industry standards.
7.What is the process for return or replacement of UC3909QTR?
All UC3909QTR units undergo pre-shipment inspection (PSI). If there is an issue with UC3909QTR, 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 UC3909QTR part is unused and in its original packaging.
Return procedure for UC3909QTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
UC3909QTR Tags
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BQ21040DBVR
Texas Instruments
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MCP73812T-420I/OT
Microchip Technology
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MCP73831T-2ACI/OT
Microchip Technology
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MCP73832T-2ACI/OT
Microchip Technology
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MCP73831T-2DCI/OT
Microchip Technology
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MCP73832T-2DCI/OT
Microchip Technology
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MCP73831T-2ATI/OT
Microchip Technology
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MCP73832T-2ATI/OT
Microchip Technology
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MCP73831T-5ACI/OT
Microchip Technology
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MCP73832T-2ACI/MC
Microchip Technology
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MCP73831T-2ACI/MC
Microchip Technology
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MCP73831T-2ATI/MC
Microchip Technology
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