BETANominal reference1.25 V · OUT minus ADJ
3 A adjustable positive regulator
LM350 Specifications
Review LM350 electrical specifications, operating conditions and package details.
Key specifications
The loop holds OUT minus ADJ near 1.25 V. R1 carries a nearly constant current and R2 lifts the adjustment pin above ground, setting the output.
Adjustment range1.2–33 V · adequate headroom required
Current class3 A · subject to safe area and cooling
Operating junction0–125 °C · standard LM350
Package details
LM350T/NOPB · TO-220
| Property | Details |
|---|---|
| Manufacturer | Texas Instruments |
| Part number | LM350T/NOPB |
| Package | TO-220 |
| Connections | 3 pins |
| Mounting | Through-hole |
| Lead pitch | 2.54 mm |
| Package code | NDE |
| Thermal reference | Output tab; use a suitable thermal path |
Operating reference
Standard LM350 · not LM350A
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Nominal adjustable output | 1.2–33 V | With sufficient input headroom and load |
| Operating junction temperature | 0–125°C | This is junction, not ambient temperature |
| Reference voltage | 1.20 / 1.25 / 1.30 V | Minimum / typical / maximum; stated electrical conditions |
| Adjustment-pin current | 50 µA typical; 100 µA maximum | Flows out of ADJUST |
| Adjustment current change | 0.2 µA typical; 5 µA maximum | 10 mA–3 A; 3–35 V differential |
| Input-to-output absolute maximum | 35 V | Differential stress limit, not an unconditional input rating |
No specifications match. Try a parameter name or a unit.
Electrical reference conditions include 3–35 V differential and specified loads; TO-220 dissipation is limited by the source footnote and thermal design.
Regulation and rejection
Manufacturer test conditions retained
Manufacturer specifications 7 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Line regulation at 25°C | 0.005%/V typical; 0.03%/V maximum | 3–35 V input-output differential |
| Line regulation over junction range | 0.02%/V typical; 0.07%/V maximum | Standard LM350 limits |
| Load regulation at 25°C | 0.1% typical; 0.5% maximum | 10 mA–3 A |
| Load regulation over junction range | 0.3% typical; 1.5% maximum | Pulse-tested at constant junction temperature |
| Thermal regulation | 0.002%/W typical; 0.03%/W maximum | 20 ms pulse; 25°C |
| Ripple rejection without CADJ | 65 dB typical | 10 V output, 120 Hz, 25°C |
| Ripple rejection with 10 µF CADJ | 66 dB minimum; 86 dB typical | 10 V output, 120 Hz; applicable full-range limit |
No specifications match. Try a parameter name or a unit.
Typical figures do not replace guaranteed limits. The LM350A column has tighter accuracy and is not used here.
Minimum load and current limiting
Cooling and differential voltage matter
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Minimum load requirement | 3.5 mA typical; 10 mA maximum | At 35 V differential |
| Current-limit capability at ≤10 V differential | 3 A minimum; 4.5 A typical | Within specified power and junction limits |
| Current limit at 30 V differential | 0.25 A minimum; 1 A typical | Safe-area protection reduces available current |
| Example divider current | 1.25 V / 110 Ω ≈11.36 mA | Nominal OUT-to-ADJ branch |
| Divider worst-case minimum | 1.20 V / 111.1 Ω ≈10.80 mA | 110 Ω resistor at +1%; above 10 mA |
| Too little output load | Output can rise above the set value | Do not rely only on typical minimum current |
No specifications match. Try a parameter name or a unit.
The 3 A label is not a guarantee at every voltage differential or without a heatsink.
Thermal path and protection
LM350T · TO-220 NDE
Manufacturer specifications 7 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Junction-to-case resistance | 3°C/W typical; 4°C/W maximum | Manufacturer NDE package reference |
| Junction-to-ambient reference | 50°C/W | No heatsink; actual mounting and airflow matter |
| Pass-stage estimate | PD ≈ (VIN − VOUT) × IOUT | Include divider current in output current |
| Example at 100 mA load | (9 − 5) × (0.100 + 0.01136) ≈0.445 W | Nominal estimate; adjustment current term is small |
| At 3 A and 4 V drop | Approximately 12 W | Requires a carefully designed thermal path |
| Built-in protections | Current, thermal and safe-area limiting | Protection is not normal operating regulation |
| Metal tab | Electrically OUTPUT | Insulate from grounded metal when required |
No specifications match. Try a parameter name or a unit.
Calculate junction temperature with case/interface/heatsink resistances and the actual ambient.
Bypass and discharge paths
Source application guidance
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Input bypass | 0.1 µF ceramic or 1 µF solid tantalum | Close to the regulator and return |
| Output capacitor | 1 µF solid tantalum or 25 µF aluminum | Improves transient response; not an arbitrary ceramic substitution |
| No output capacitor | The regulator can be stable without one | Certain small capacitances can cause ringing |
| Adjustment bypass | 10 µF improves ripple rejection | Optional; evaluate discharge protection |
| Output discharge protection | Review for large stored output charge | Source states ≤25 µF output capacitors need no diode in its discussed case |
| Adjustment discharge protection | Depends on CADJ and output voltage | Follow source Figure 17 for larger capacitance / voltage cases |
No specifications match. Try a parameter name or a unit.
The example uses 0.1 µF input and 1 µF tantalum output, with no ADJ bypass. Review protection if external supplies or stored charge can drive the output.
Nominal 9 V-to-5 V supply
110 Ω / 330 Ω divider · 50 Ω load
Manufacturer specifications 7 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| R1; OUT2 to ADJ1 | 110 Ω, 1% | Dissipates about 14.2 mW at nominal reference |
| R2; ADJ1 to GND | 330 Ω, 1% | Nominal ratio R2/R1 = 3 |
| Ideal output | 1.25 × (1 + 330/110) = 5.00 V | Before IADJ and tolerances |
| Including typical adjustment current | 5.0165 V | Adds 50 µA × 330 Ω |
| Load resistor | 50 Ω, at least 1 W | Nominal 100 mA and 0.5 W |
| Nominal total output current | 111.36 mA | Load plus divider; small IADJ contribution omitted |
| Return connections | Input return, R2, load and capacitor returns | Same GND net; ADJ is not GND |
No specifications match. Try a parameter name or a unit.
Use adequate resistor/capacitor ratings and verify the actual loaded voltage.
Package and limits
LM350T/NOPB · TO-220
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Front-view leads | 1 ADJUST; 2 OUTPUT; 3 INPUT | Marking toward you, leads down |
| Lead pitch | 2.54 mm | Vertical three-lead footprint |
| Tab connection | OUTPUT | Not ground |
| Selected package | TO-220 NDE | Original TEP geometry and starting footprint |
| Other source package | TO-3 is described in the manufacturer sheet | Different physical terminal arrangement; not interchangeable footprint |
| Storage temperature | −65 to +150°C | Unpowered storage |
No specifications match. Try a parameter name or a unit.
This page publishes the verified TO-220 variant; no unsupported SMD substitute is implied.
Connections by function
Select a pin for its function, connection guidance and electrical notes.