LM109 Extended Temperature 1A 5V Output Linear Regulator / LDO | TI.com


Extended Temperature 1A 5V Output Linear Regulator / LDO

Extended Temperature 1A 5V Output Linear Regulator / LDO - LM109


The LM109 series are complete 5V regulators fabricated on a single silicon chip. They are designed for local regulation on digital logic cards, eliminating the distribution problems association with single-point regulation. The devices are available in two standard transistor packages. In the solid-kovar TO-5 header, it can deliver output currents in excess of 200 mA, if adequate heat sinking is provided. With the TO-3 power package, the available output current is greater than 1A.

The regulators are essentially blowout proof. Current limiting is included to limit the peak output current to a safe value. In addition, thermal shutdown is provided to keep the IC from overheating. If internal dissipation becomes too great, the regulator will shut down to prevent excessive heating.

Considerable effort was expended to make these devices easy to use and to minimize the number of external components. It is not necessary to bypass the output, although this does improve transient response somewhat. Input bypassing is needed, however, if the regulator is located very far from the filter capacitor of the power supply. Stability is also achieved by methods that provide very good rejection of load or line transients as are usually seen with TTL logic.

Although designed primarily as a fixed-voltage regulator, the output of the LM109 series can be set to voltages above 5V, as shown. It is also possible to use the circuits as the control element in precision regulators, taking advantage of the good current-handling capability and the thermal overload protection.


  • Specified to be compatible, worst case, with TTL and DTL
  • Output current in excess of 1A
  • Internal thermal overload protection
  • No external components required

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Parametrics Compare all products in Linear regulators (LDO)

Output Options
Iout (Max) (A)
Vin (Max) (V)
Vin (Min) (V)
Vout (Max) (V)
Vout (Min) (V)
Fixed output options (V)
Package Group
Regulated Outputs (#)
Operating Temperature Range (C)
Thermal Resistance θJA (°C/W)
Noise (uVrms)
Approx. price (US$)
Output Capacitor Type
PSRR @ 100KHz (dB)
Accuracy (%)
Vdo (Typ) (mV)
Iq (Typ) (mA)
Package Size: mm2:W x L (PKG)
LM109 LM350-N
Fixed Output     Adjustable Output    
1     3    
35     35    
7.1     4.2    
5     32    
5     1.25    
TO-3 | 2
TO | 3    
TO-220 | 3    
N/A     N/A    
1     1    
-55 to 150     0 to 125    
35     35    
40     13    
6.75 | 1ku     0.70 | 1ku    
Catalog     Catalog    
64     40    
4     3    
3000     2300    
5.2     0.05    
3TO: 92 mm2: 9.14 x 10.03 (TO | 3)
2TO-3: 969 mm2: 24.89 x 38.94 (TO-3 | 2)    
See datasheet (TO-220)