LM337K STMicroelectronics, LM337K Datasheet - Page 10

• Manufacturer Part Number: LM337K
• Description: IC VOLT REG NEG ADJ 1.5A TO-3
• Manufacturer: STMicroelectronics

Specifications of LM337K

• Regulator Topology: Negative Adjustable
• Voltage - Output: -1.2 ~ -37 V
• Number Of Regulators: 1
• Operating Temperature: 0°C ~ 125°C
• Mounting Type: Through Hole
• Package / Case: TO-204, TO-3
• Polarity: Negative
• Number Of Outputs: 1
• Output Type: Adjustable
• Output Voltage: - 1.2 V to - 37 V
• Output Current: 1.5 A
• Line Regulation: 0.04 % / V
• Load Regulation: 1 %
• Input Voltage Max: 40 V
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: 0 C
• Maximum Power Dissipation: 20000 mW
• Mounting Style: Through Hole
• Reference Voltage: - 1.287 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Voltage - Input: -
• Voltage - Dropout (typical): -
• Current - Limit (min): -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-7331; LM337K

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Thermal regulation
When power is dissipated in an IC, a temperature gradient occurs across the IC chip
affecting the individual IC circuit components. With an IC regulator, this gradient can be
especially severe since power dissipation is large.
Thermal regulation is the effect of these temperature gradients on output voltage (in
percentage output change) per watt of power change in a specified time. Thermal regulation
error is independent of electrical regulation or temperature coefficient, and occurs within 5
ms to 50 ms after a change in power dissipation. Thermal regulation depends on IC layout
as well as electrical design. The thermal regulation of a voltage regulator is defined as the
percentage change of V
The LM137 specification is 0.02 %/W max. In
mV for 0.03% of V
thus well inside the specification limit of 0.02 %/W x 10 W = 0.2% max. When the 10 W
pulse is ended the thermal regulation again shows a 3 mV step as the LM137 chip cools off.
Note that the load regulation error of about 8 mV (0.08 %) is additional to the thermal
regulation error.
In
the drift in the first 10 ms and the thermal error stays well within 0.1% (10 mV).
Figure
2, when the 10 W pulse is applied for 100 ms, the output drifts only slightly beyond
O
= – 10 V) when a 10 W pulse is applied for 10 ms. This performance is
O
, per watt, within the first 10ms after a step of power, is applied.
Figure
1, a typical LM337’s output drifts only 3