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Texas Instruments TL497AIN
- Part No.:
- TL497AIN
- Manufacturer:
- Texas Instruments
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
TL497AIN.pdf
- Description:
- IC REG BUCK BST ADJ 500MA 14PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:205
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Product details
Overview
TL497AIN from Texas Instruments is a fixed-on-time, variable-frequency switching voltage regulator controller IC designed for step-up, step-down, and inverting DC-DC conversion. It integrates an internal 500 mA NPN power switch, 1.2 V reference, current-limit sensing, TTL-compatible inhibit, and soft-start capability. It operates from 4.5 V to 12 V input and supports output voltages up to ±30 V in buck/boost/invert topologies - used in industrial power supplies and battery-powered instrumentation.
For engineers reviewing the TL497AIN datasheet, TL497AIN pinout, TL497AIN application, or TL497AIN equivalent, this page delivers verified functional identity, thermal-rated PDIP-14 package details, confirmed 500 mA peak switch current, adjustable output via R1/R2 feedback, and real-world design constraints including CT-based on-time programming and 0.7 V current-limit threshold.
Technical Context
The TL497AIN implements a fixed-on-time control architecture where switch conduction duration is set by an external timing capacitor (CT) charged by an internal constant-current source proportional to VCC - ensuring stable on-time across 4.5–12 V supply range. Its oscillator drives an internal NPN transistor with uncommitted collector/emitter terminals, enabling direct use in low-power configurations or external transistor drive for higher current.
Regulation is achieved via high-gain comparator comparing feedback voltage (from R1/R2 divider) against a 1.2 V substrate-referenced reference. Current limiting is implemented by sensing voltage across RCL; activation occurs at 0.7 V threshold. Inhibit logic disables oscillation when INHIBIT pin exceeds 2.5 V, providing TTL-compatible shutdown.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 4.5 V to 12 V - defines minimum startup voltage and maximum safe operating rail for internal circuitry and switch driver. |
| Peak Switch Current | 500 mA - maximum continuous pulsed current through internal NPN transistor; limits usable output power in basic configurations. |
| Reference Voltage | 1.2 V (substrate-referenced) - sets regulation point for feedback network; determines output voltage formula VO = 1.2 × (1 + R1/R2). |
| Current Limit Threshold | 0.7 V across RCL - sets peak inductor current limit; RCL = 0.7 V / IPk enables precise overcurrent protection tuning. |
| Switch On-State Voltage | 0.85 V at 500 mA - contributes directly to conduction loss and efficiency; impacts thermal design in high-duty-cycle applications. |
| Operating Temperature | −40°C to +85°C - qualified for extended industrial environments; distinguishes TL497AIN from commercial-grade TL497AC variants. |
| Package Thermal Impedance | 101°C/W (θJA, PDIP) - determines junction-to-ambient temperature rise under load; critical for derating at full 500 mA switching. |
Pinout & Package
TL497AIN is supplied in a 14-pin plastic dual in-line package (PDIP-N), 13.97 mm wide, with 2.54 mm lead pitch and through-hole mounting. The package has no exposed pad and is rated for lead-free (NIPDAU) finish with no MSL restriction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (COMP INPUT) | Feedback comparator input | Receives resistor-divider voltage; compared to 1.2 V reference to regulate output. |
| 2 (INHIBIT) | Digital enable/disable control | TTL-compatible input; high ≥2.5 V disables switching; low ≤0.8 V enables operation. |
| 3 (FREQ CONTROL) | Timing capacitor connection | Connects to CT ground; internal current charges CT to set fixed on-time (e.g., 44 µs @ 500 pF). |
| 4 (SUBSTRATE) | Reference node for 1.2 V reference | Must be connected to system ground or lowest potential node; reference is substrate-referenced, not GND-referenced. |
| 5 (GND) | Power and signal ground return | Common return for VCC, feedback, and current sense paths; separate from SUBSTRATE in layout-critical designs. |
| 6 (CATHODE) | Internal Schottky diode cathode | Used in boost/invert configurations as catch diode anode connection point; rated for 500 mA forward current. |
| 7 (ANODE) | Internal Schottky diode anode | Connected internally to emitter of internal NPN; provides commutation path during switch-off phase. |
| 8 (VCC) | Positive supply input | Power rail for internal logic, oscillator, and base drive; must be decoupled near pin with ≥1 µF ceramic capacitor. |
| 9 (CUR LIM SENS) | Current limit sense input | Monitors voltage across external RCL; triggers current limit when ≥0.7 V develops across RCL. |
| 10 (BASE DRIVE) | Test-only terminal | No functional role in circuit operation; reserved for factory testing only; leave unconnected. |
| 11 (BASE) | Test-only terminal | No functional role in circuit operation; reserved for factory testing only; leave unconnected. |
| 12 (COL OUT) | Internal NPN collector output | Switching node for inductor connection in boost/buck/invert topologies; handles 500 mA peak current. |
| 13 (NC) | No internal connection | Unbonded pin; electrically isolated; may be left floating or tied to GND for mechanical stability. |
| 14 (EMIT OUT) | Internal NPN emitter output | Return path for internal switch; connects to GND in boost, to input in buck, or to virtual ground in inverting config. |
Key Features
| Feature | Design Value |
|---|---|
| Configurable topology support | Enables buck, boost, and inverting regulator designs using same IC - reduces BOM count and simplifies platform power architecture. |
| Adjustable output voltage | Set via external R1/R2 feedback network - allows precise output tuning from 1.2 V up to 30 V (step-up) or −30 V (inverting). |
| Soft start-up capability | Prevents inrush current and output overshoot during power-on - eliminates need for external soft-start circuitry or sequencing controllers. |
| Input and output regulation | 0.2% typical input regulation and 0.4% typical output regulation - ensures stable output despite line/load variations in sensitive analog systems. |
| TTL-compatible inhibit | Direct interface with microcontroller GPIO or system enable signals - enables synchronized power sequencing without level-shifting. |
Applications
| Industrial Sensor Power Supply | Battery-Powered Data Logger |
|---|---|
|
Use Scenario: Powers 3.3 V or 5 V analog front-end and ADC in remote environmental monitoring nodes powered by two AA cells (1.8–3.2 V). IC Role / Device Role / Timing Role: TL497AIN acts as step-up controller driving external inductor and Schottky diode to generate regulated 5 V from declining battery voltage. Use Value: Maintains stable sensor bias and ADC reference despite battery droop; −40°C to +85°C rating ensures field reliability in outdoor enclosures. |
Use Scenario: Supplies 3.3 V to ultra-low-power MCU and flash memory in portable asset-tracking devices with Li-SOCl₂ primary battery (3.6 V nominal). IC Role / Device Role / Timing Role: TL497AIN configured as inverting regulator generates −5 V for op-amp bias rails while sharing same inductor with main 3.3 V buck stage. Use Value: Dual-rail generation from single inductor reduces component count and board area; internal 1.2 V reference enables accurate feedback across temperature. |
| Programmable Logic Controller (PLC) Auxiliary Rail | Test Equipment DC-DC Module |
|
Use Scenario: Generates isolated 12 V auxiliary supply from 24 V industrial bus for optocoupler drivers and level-shifting circuits in modular PLC backplanes. IC Role / Device Role / Timing Role: TL497AIN operates in step-down mode with external MOSFET driver to deliver 12 V @ 200 mA, leveraging its adjustable current limit for short-circuit protection. Use Value: Programmable RCL-based current limit avoids fuse replacement in field units; 101°C/W θJA allows convection-cooled design in sealed enclosures. |
Use Scenario: Embedded in benchtop multimeter power subsystem to generate ±15 V rails for analog signal conditioning stages from 12 V input. IC Role / Device Role / Timing Role: TL497AIN used in dual configuration: one as boost (for +15 V), one as inverter (for −15 V), both sharing same CT timing capacitor for matched switching frequency. Use Value: Fixed-on-time architecture ensures consistent regulation performance across input voltage drift; internal Schottky diode reduces external component count per rail. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switching regulator controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2577-ADJ | Fixed-frequency PWM (52 kHz), integrated 3 A switch, no internal Schottky diode, requires external diode. | Higher output current capability but less flexible topology support; lacks inverting mode and substrate-referenced reference. | Choose LM2577-ADJ for higher-power step-up needs (>500 mA); TL497AIN preferred for multi-topology prototyping or inverting outputs. |
| UC3843B | Current-mode PWM controller, 1 A gate driver, no integrated switch or diode, requires external MOSFET and diode. | Greater design flexibility and higher efficiency at >100 kHz, but demands more external components and loop compensation effort. | Choose UC3843B for optimized high-efficiency SMPS designs; TL497AIN suits cost-sensitive, low-component-count industrial converters. |
Compared with LM2577-ADJ and UC3843B, the TL497AIN offers unique integration of topology flexibility, internal switch, and substrate-referenced feedback - making it optimal for compact, multi-rail, temperature-stable industrial DC-DC modules where design simplicity and extended temperature operation are prioritized over raw power density.
Availability
TL497AIN is available at Aetrix Electronics and suitable for industrial sensor power supplies, battery-powered data loggers, programmable logic controller auxiliary rails, and test equipment DC-DC modules requiring stable component supply across −40°C to +85°C operation.
Supply support for TL497AIN 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 precision analog ICs and industrial-grade power solutions.
The TL497A product line was engineered for robust, low-component-count DC-DC conversion in harsh industrial environments - emphasizing topology versatility, wide temperature operation, and ease of implementation without complex compensation networks.
FAQ
What is the maximum output voltage achievable with TL497AIN in boost configuration?
The TL497AIN supports up to 30 V output in step-up configuration, as specified in recommended operating conditions. This limit arises from the 35 V absolute maximum rating on the COL OUT and CATHODE pins, with 5 V headroom reserved for safety margin and transient spikes. Output voltage is set by the R1/R2 feedback network relative to the 1.2 V internal reference, and stability must be verified with appropriate output capacitance and inductor selection per the design equations in the datasheet. The TL497AIN itself does not regulate beyond 30 V in standard boost layouts.
Does TL497AIN require an external Schottky diode in all configurations?
No - the TL497AIN integrates a matched Schottky diode between ANODE and CATHODE pins, which is fully functional in boost and inverting configurations. It is explicitly intended for blocking and commutation roles, eliminating the need for an external diode in basic implementations. However, in high-current or high-efficiency applications exceeding 500 mA, or where lower forward voltage is required, an external Schottky diode may be substituted. The internal diode is not used in step-down (buck) mode, where external diode placement differs.
How is the switching frequency determined for TL497AIN?
The TL497AIN uses fixed-on-time, variable-frequency control: its switch on-time (ton) is set by an external capacitor (CT) connected from FREQ CONTROL to GND, with ton ≈ 12 × CT (e.g., 44 µs for 500 pF). Off-time varies with input/output voltage and load, so actual switching frequency changes dynamically - typically ranging from ~10 kHz to >100 kHz depending on operating point. Frequency cannot be fixed externally; it is inherently load- and line-dependent, unlike PWM controllers with crystal or resistor-set oscillators.
Can TL497AIN operate with input voltage below 4.5 V?
No - the TL497AIN is not characterized or guaranteed to operate below 4.5 V input. Recommended operating conditions specify a minimum VCC of 4.5 V, and electrical characteristics (e.g., reference voltage accuracy, switch on-state voltage) are only validated within 4.5–12 V. Below 4.5 V, internal biasing fails, reference drifts, and the internal transistor may not saturate properly, leading to erratic regulation or complete failure. For sub-4.5 V inputs, consider dedicated low-VIN regulators such as TPS61040 or MAX1771.
What is the purpose of the SUBSTRATE pin on TL497AIN, and how should it be connected?
The SUBSTRATE pin provides the reference node for the internal 1.2 V bandgap reference - it is substrate-referenced, not GND-referenced. It must be connected to the most negative potential in the system (typically circuit ground), especially in inverting or floating-output configurations. Incorrect connection (e.g., leaving open or tying to noisy ground planes) causes reference inaccuracy and output regulation errors. In PCB layout, SUBSTRATE should have low-impedance, dedicated trace to clean ground, separate from high-current GND returns.
TL497AIN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 14-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- Step-Up, Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 12V
- Voltage - Output (Min/Fixed):
- ±1.2V
- Voltage - Output (Max):
- 30V, -25V
- Current - Output:
- 500mA (Switch)
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 14-PDIP
TL497AIN FAQ
1.How can I place an order for TL497AIN through Aetrix?
Please submit a Request for Quotation (RFQ) for TL497AIN 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 TL497AIN reliable?
The price and inventory of TL497AIN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL497AIN is usually 5 days.
3.What payment methods are accepted for TL497AIN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL497AIN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL497AIN?
TL497AIN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL497AIN 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 TL497AIN?
For technical support, including TL497AIN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL497AIN requirements.
6.How does Aetrix verify that TL497AIN is sourced from the original manufacturer or authorized distributors?
All TL497AIN 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 TL497AIN meets industry standards.
7.What is the process for return or replacement of TL497AIN?
All TL497AIN units undergo pre-shipment inspection (PSI). If there is an issue with TL497AIN, 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 TL497AIN part is unused and in its original packaging.
Return procedure for TL497AIN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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