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LM317KTTRG3
Texas Instruments
IC REG LIN POS ADJ 1.5A DDPAK
18262 Pcs New Original In Stock
Linear Voltage Regulator IC Positive Adjustable 1 Output 1.5A TO-263 (DDPAK-3)
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5.0 / 5.0
- (159 Ratings)
LM317KTTRG3
Product Overview
1338598
DiGi Electronics Part Number
LM317KTTRG3-DGManufacturer
Texas Instruments
LM317KTTRG3
Description
IC REG LIN POS ADJ 1.5A DDPAKInventory
18262 Pcs New Original In Stock
Linear Voltage Regulator IC Positive Adjustable 1 Output 1.5A TO-263 (DDPAK-3)
Quantity
Minimum 1
Minimum 1
Purchase and inquiry
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LM317KTTRG3 Technical Specifications
Category
Power Management (PMIC), Voltage Regulators - Linear, Low Drop Out (LDO) Regulators
Packaging
Tape & Reel (TR)
Series
-
Product Status
Active
Output Configuration
Positive
Output Type
Adjustable
Number of Regulators
1
Voltage - Input (Max)
40V
Voltage - Output (Min/Fixed)
1.25V
Voltage - Output (Max)
37V
Voltage Dropout (Max)
-
Current - Output
1.5A
Current - Quiescent (Iq)
10 mA
PSRR
80dB ~ 65dB (120Hz)
Control Features
-
Protection Features
Over Current, Over Temperature, Short Circuit
Operating Temperature
0°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
TO-263-4, D2PAK (3 Leads + Tab), TO-263AA
Supplier Device Package
TO-263 (DDPAK-3)
Base Product Number
LM317
Datasheet & Documents
Manufacturer Product Page
LM317KTTRG3 Specifications
HTML Datasheet
LM317KTTRG3-DG
Environmental & Export Classification
RoHS Status
ROHS3 Compliant
Moisture Sensitivity Level (MSL)
3 (168 Hours)
REACH Status
REACH Unaffected
ECCN
EAR99
HTSUS
8542.39.0001
Additional Information
Other Names
296-50349-1
LM317KTTRG3-DG
296-50349-2
296-50349-6
Standard Package
500
Reviews
5.0/5.0-(Show up to 5 Ratings)
Dec 02, 2025
Overall, DiGi Electronics excels in inventory management and post-sale customer support.
Dec 02, 2025
The packaging was impeccable, ensuring the product arrived in perfect condition, which truly enhanced my shopping experience.
Dec 02, 2025
The support staff is knowledgeable and helpful, ensuring my issues are resolved efficiently.
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Frequently Asked Questions (FAQ)
What are the critical thermal design considerations when using the LM317KTTRG3 in a high-current surface-mount application?
When using the LM317KTTRG3 at load currents approaching 1.5A, thermal management is critical due to power dissipation in the TO-263 package. The junction-to-ambient thermal resistance (θJA) is highly dependent on PCB layout. To avoid overheating, use a large copper area (especially connected to the tab) for heat spreading, multiple vias to internal ground planes, and consider limiting ambient temperature or adding forced airflow. Always calculate worst-case power loss (Vin - Vout) × Iout and confirm TJ remains below 125°C with margin. For continuous 1.5A operation, a heatsink or thermal pad may be necessary even with optimal layout.
How does the LM317KTTRG3 compare to the LT1086-3.3 in terms of dropout voltage and suitability for low-headroom applications?
The LM317KTTRG3 has a typical dropout voltage of around 2V to 3V under full load, making it less suitable for low-headroom applications compared to the LT1086-3.3, which offers a dropout as low as 1.2V at 1.5A. If your input voltage is only slightly above the desired output (e.g., 5V to 3.3V), the LM317KTTRG3 may not regulate reliably, especially at high temperature or full load. For such cases, consider a modern LDO like the LT1086-3.3 or TPS7A47 for better efficiency and thermal performance. The LM317KTTRG3 remains viable only when sufficient headroom (≥3V) is available.
Can the LM317KTTRG3 be safely used as a drop-in replacement for the LM317T in a TO-220-based design, and what layout adjustments are needed?
Yes, the LM317KTTRG3 (TO-263 surface-mount) can replace the through-hole LM317T, but thermal performance must be carefully re-evaluated. The TO-263 package relies on PCB copper for heatsinking, whereas TO-220 typically uses an external heatsink. You must redesign the PCB to include a large thermal pad connected to internal planes and sufficient copper area. Also ensure proper solder profile for reflow and verify mechanical stability under vibration. Without adequate thermal design, the surface-mount version may overheat even at moderate loads.
What are the risks of using the LM317KTTRG3 without input and output capacitors in noise-sensitive analog circuits?
While the LM317KTTRG3 is stable without capacitors in basic operation, omitting them increases noise and reduces transient response, especially in sensitive analog designs. A 0.1µF ceramic capacitor on the input near the device improves high-frequency noise rejection, and a 10µF tantalum or aluminum electrolytic on the output enhances stability and PSRR (especially in the 120Hz range). Without these, load transients can cause overshoot or oscillation. For precision applications, always include recommended capacitors to ensure reliable regulation and meet specified PSRR of 65–80dB.
How do the built-in protection features of the LM317KTTRG3 perform under sustained over-current or short-circuit conditions, and what are the reliability implications?
The LM317KTTRG3 includes internal current limiting, short-circuit protection, and thermal shutdown. However, sustained short-circuit events can cause repeated thermal cycling, leading to long-term reliability degradation. While the device will limit current and shut down when overheated, it may not survive indefinite fault conditions without proper external design. To enhance reliability, add a fuse or polyfuse on the input, ensure adequate heatsinking, and avoid prolonged operation in fault mode. Devices like the TPS7A47 offer more robust fault handling, but the LM317KTTRG3 remains reliable if used within its protection limits and with good system-level design.
Quality Assurance (QC)
DiGi ensures the quality and authenticity of every electronic component through professional inspections and batch sampling, guaranteeing reliable sourcing, stable performance, and compliance with technical specifications, helping customers reduce supply chain risks and confidently use components in production.
LM317KTTRG3 CAD Models
Texas Instruments LM317KTTRG3 PCB symbols & footprints
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