S1F76540 Series
Changing the temperature coefficient:
•The temperature coefficient of the regulated voltage depends on the temperature coefficient of the reference voltage (if the division ratio of setup resistors does not depend on the temperature). It is necessary to change the temperature coefficient using thermistors, resistors or others to set any other temperature coefficient of the regulated voltage. The following explains how to calculate the VREG voltage in temperature T.
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| CTR2 × R2 | (T0) |
| CT |
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VREG (T) = {1 + |
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| } × [1+ (T – T)0 | × |
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CTR1 × R1 | (T0) | |||||||
T0 | : 25°C |
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CTR1 | : Temperature coefficient of resistor R1 (Ratio to the value at 25°C) | |||||||
CTR2 | : Temperature coefficient of resistor R2 (Ratio to the value at 25°C) | |||||||
CT | : Temperature coefficient of internal reference voltage (%/°C) |
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R1 (T0) | : R1 value (Ω) at 25°C |
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R2 (T0) | : R2 value (Ω) at 25°C |
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VREF (T0) | : Internal reference voltage (V) at 25°C |
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If the temperature coefficient of R1 and R2 is identical in equation (3), the VREG voltage depends on the temperature coefficient of internal reference voltage only.
Application notes on voltage regulator circuit:
•To satisfy the absolute maximum ratings of the S1F76540, the setup resistor(s) must be inserted between VDD and VREG pins of the S1F76540 that uses the voltage regulator. The S1F76540 IC itself may be degraded or destroyed if the R1 resistor is connected to pin VDD of S1F76540 that does not use the regulator during serial connection.
•The regulation voltage adjustment input (pin RV) has the very high input impedance, and its noise insertion can drop the regulator stability. As shown in Figure 2.5, shield the cable between the division resistor and RV pin or use a cable as short as possible between them.
S1F76540 | Series |
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S1F70000 Series Technical Manual
EPSON |