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Product details
Overview
KA337 from onsemi is a 3-terminal adjustable negative voltage regulator delivering up to 1.5 A across an output range of −1.2 V to −37 V. It functions as a floating linear regulator in local on-board power regulation, employs internal current limiting and thermal shutdown, and requires only two external resistors (R1 = 120 Ω, R2 variable) for output programming. Its reference voltage is −1.25 V typical between output and adjustment terminals.
For engineers reviewing the KA337 datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed 1.5 A output capability at −37 V max, thermal shutdown activation at +125°C junction temperature, −1.25 V reference accuracy (±30 mV), and compatibility with standard TO-220AB and D2PAK packages for industrial power supply designs.
Technical Context
The KA337 operates as a floating negative regulator: its output voltage is set by a resistor divider between adjustment and ground, with a fixed −1.25 V reference between output and adjust pins. Regulation relies on internal bandgap reference, error amplifier, and pass transistor with safe-area compensation.
It integrates three protection mechanisms: constant-current short-circuit limiting independent of temperature, thermal overload shutdown at TJ ≥ +125°C, and internal safe-area compensation to prevent second breakdown during high-voltage/low-current operation. Dropout voltage is not specified as a standalone parameter but is implied by minimum input-output differential of 3.0 V for stable regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 1.5 A maximum - supports high-current analog rails and op-amp supplies without external boost. |
| Output Voltage Range | −1.2 V to −37 V - enables programmable negative bias for op-amps, RF mixers, and instrumentation amplifiers. |
| Reference Voltage | −1.25 V ±30 mV - defines precision of output setting; used directly in VOUT = −1.25 V × (1 + R2/R1) + IADJ×R2. |
| Line Regulation | 0.04 %/V max - ensures ≤4 mV change per 10 V input variation at fixed load, critical for unregulated DC bus inputs. |
| Load Regulation | 50 mV max for |VOUT| ≤ 5 V - guarantees tight voltage stability across 10 mA to 1.5 A load steps in precision analog systems. |
| Thermal Shutdown Threshold | +125°C junction - protects against sustained overloads or inadequate heatsinking in enclosed enclosures. |
| Ripple Rejection | 66 dB min at 120 Hz - suppresses rectified AC ripple in linear power supplies feeding sensitive analog circuitry. |
Pinout & Package
KA337 is available in TO-220AB (Case 221AB) and D2PAK (Case 936) packages. The TO-220AB variant uses a standard 3-lead transistor outline with heatsink surface electrically connected to Pin 2 (Vin). D2PAK adds a fourth terminal (Tab/Heatsink) tied to Pin 2.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (Adjust) | Reference node input | Connects to voltage divider midpoint; draws ≤100 µA; sets output via VREF = −1.25 V relative to Pin 3. |
| Pin 2 (Vin) | Negative input supply | Accepts −3.0 V to −40 V input; heatsink surface is electrically tied to this pin in both TO-220AB and D2PAK. |
| Pin 3 (Vout) | Regulated negative output | Delivers −1.2 V to −37 V; must sustain ≥1.5 mA minimum load current to maintain regulation. |
Key Features
| Feature | Design Value |
|---|---|
| Floating architecture | Enables high-voltage negative bias generation (e.g., −100 V input → −37 V output) without ground-referenced constraints. |
| Internal safe-area compensation | Prevents secondary breakdown in the pass transistor during high-VIN/low-IOUT conditions common in lab power supplies. |
| Constant-current short-circuit limiting | Maintains ~1.5 A foldback current regardless of junction temperature, enabling robust fault handling without external sensing. |
| Thermal shutdown with hysteresis | Shuts down at +125°C and restarts near +110°C, preventing thermal cycling damage during transient overloads. |
| Pb-free RoHS-compliant packaging | TO-220AB (T suffix) and D2PAK (D2T suffix) variants meet EU RoHS Directive 2011/65/EU and JEDEC J-STD-020 moisture sensitivity level 1. |
Applications
| Operational Amplifier Bias Supply | Programmable Lab Power Supply |
|---|---|
Use Scenario: Providing dual-rail ±15 V or ±12 V supplies for precision op-amps in test equipment and signal conditioning circuits. IC Role / Device Role / Timing Role: Negative linear regulator generating stable low-noise −15 V rail from unregulated −24 V DC input. Use Value: Delivers 1.5 A with ≤50 mV load regulation and 66 dB ripple rejection, ensuring op-amp PSRR performance remains uncompromised. | Use Scenario: Adjustable benchtop power supply with user-set negative output from −1.2 V to −30 V. IC Role / Device Role / Timing Role: Core negative voltage regulation stage controlled by front-panel potentiometer (R2) and fixed R1 = 120 Ω. Use Value: Eliminates need for multiple fixed-voltage regulators; −1.25 V reference tolerance (±30 mV) enables ±1% output accuracy across full range. |
| Industrial Sensor Signal Conditioning | RF Mixer Local Oscillator Bias |
Use Scenario: Powering bridge-based strain gauge or RTD signal chains requiring low-drift negative bias for instrumentation amplifiers. IC Role / Device Role / Timing Role: Local on-card negative regulator placed adjacent to sensor front-end ICs to minimize noise coupling. Use Value: 0.04 %/V line regulation and 0.6% temperature stability ensure <100 µV drift over 40°C ambient range in metrology-grade systems. | Use Scenario: Supplying −5 V to −12 V bias to GaAs FET-based active mixers in microwave receivers. IC Role / Device Role / Timing Role: Low-noise negative rail generator with CADJ = 10 µF to suppress switching noise from upstream DC/DC converters. Use Value: 15 dB ripple rejection improvement with CADJ enables clean LO injection, reducing mixer phase noise floor by >3 dB. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable negative voltage regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM337T | Identical electrical specs and pinout; KA337 is onsemi's rebranded LM337 variant with same TO-220AB package and −40°C to +125°C rating. | No functional difference; both support identical circuits and thermal derating curves. | Select KA337 when sourcing from onsemi-dedicated supply chain or for BOM consolidation under onsemi part numbering. |
| LT1033CS8#PBF | Lower max current (100 mA), higher reference accuracy (−1.235 V ±0.5%), wider temp range (−55°C to +150°C), SO-8 package. | Suitable for low-power precision analog where size and accuracy outweigh current needs; not drop-in for 1.5 A loads. | Choose LT1033 for aerospace or extended-temp instrumentation where 100 mA suffices and SO-8 footprint is preferred. |
Compared with LM337T, KA337 offers identical performance and compatibility but reflects onsemi's current branding and logistics; versus LT1033, KA337 trades precision and package size for 15× higher output current and direct TO-220AB/D2PAK mounting-critical for industrial power stages.
Availability
KA337 is available at Aetrix Electronics and suitable for industrial power supplies, test equipment design, and analog signal chain biasing requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for KA337 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier focused on energy-efficient electronics for automotive, industrial, cloud, and IoT applications.
The KA337 belongs to onsemi's legacy linear regulator product line, designed specifically for robust, cost-effective negative voltage regulation in industrial and instrumentation power systems where reliability and thermal resilience are prioritized over ultra-low quiescent current.
FAQ
What is the minimum load current required for KA337 to maintain regulation?
The KA337 requires a minimum load current of 1.5 mA when |VIN − VOUT| ≤ 10 V, and 2.5 mA when |VIN − VOUT| ≤ 40 V to maintain output regulation. This is due to internal quiescent current being returned to the output pin; insufficient load causes VOUT to rise above the set value. Always verify minimum load in final PCB layout using worst-case VIN/VOUT differentials.
Can KA337 be used in parallel for higher current output?
No, KA337 is not designed for parallel operation. Its output voltage tolerance (±30 mV on −1.25 V reference) and lack of current-sharing features mean mismatched units will cause one device to dominate conduction, leading to thermal runaway. For >1.5 A, use a single higher-current regulator or switch-mode solution instead of paralleling KA337 devices.
What capacitor types are recommended for KA337 stability and why?
KA337 requires a 1.0 µF solid tantalum or 10 µF aluminum electrolytic capacitor at the output (CO) for stability. Low-ESR ceramics or polymer capacitors are explicitly discouraged-they reduce phase margin and can cause oscillation. Input bypass (CIN) should also be 1.0 µF tantalum. These recommendations stem from the regulator's internal compensation optimized for traditional electrolytic/tantalum ESR profiles.
Does KA337 support adjustable current regulation mode?
Yes, KA337 can function as a precision current regulator by connecting a fixed resistor between the adjustment and output pins. In this configuration, the −1.25 V reference forces a constant current IOUT = −1.25 V / RSET through the load. This mode retains thermal shutdown and current limiting, making it suitable for LED bias or sensor excitation where voltage regulation is secondary to current accuracy.
What is the maximum allowable input-output voltage differential for KA337?
The absolute maximum input-output voltage differential for KA337 is 40 V DC, as specified in the Absolute Maximum Ratings table. Exceeding this risks junction breakdown. For reliable operation, keep |VIN − VOUT| ≤ 37 V in continuous use, and ensure power dissipation stays within thermal limits-e.g., at 1.5 A and 30 V differential, PD ≈ 45 W requires substantial heatsinking even with low RθJC.
KA337 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-220-3
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Output Configuration:
- Negative
- Output Type:
- Adjustable
- Number of Regulators:
- 1
- Voltage - Input (Max):
- -40V
- Voltage - Output (Min/Fixed):
- -1.2V
- Voltage - Output (Max):
- -37V
- Voltage Dropout (Max):
- -
- Current - Output:
- 1.5A
- Current - Quiescent (Iq):
- -
- Current - Supply (Max):
- -
- PSRR:
- 60dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Temperature, Short Circuit
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-3
KA337 FAQ
1.How can I place an order for KA337 through Aetrix?
Please submit a Request for Quotation (RFQ) for KA337 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 KA337 reliable?
The price and inventory of KA337 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KA337 is usually 5 days.
3.What payment methods are accepted for KA337?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KA337 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KA337?
KA337 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KA337 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 KA337?
For technical support, including KA337 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KA337 requirements.
6.How does Aetrix verify that KA337 is sourced from the original manufacturer or authorized distributors?
All KA337 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 KA337 meets industry standards.
7.What is the process for return or replacement of KA337?
All KA337 units undergo pre-shipment inspection (PSI). If there is an issue with KA337, 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 KA337 part is unused and in its original packaging.
Return procedure for KA337:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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