ZHCSIY5A October 2018 – May 2019 LMZM33604
PRODUCTION DATA.
A resistor divider connected to the FB pin (pin 15) programs the output voltage of the LMZM33604. The output voltage adjustment range is from 1 V to 20 V. Figure 31 shows the feedback resistor connection for setting the output voltage. The recommended value of RFBB is 10 kΩ. The value for RFBT can be calculated using Equation 1.
Table 1 lists the standard external RFBT values for several standard output voltages along with the recommended switching frequency (FSW) and the frequency setting resistor (RRT) for each of the output voltages listed. (See Voltage Dropout for the allowable output voltage as a function of input voltage.)
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where
VOUT (V) | RFBT (kΩ)(1) | fSW (kHz) | RRT (kΩ) |
---|---|---|---|
1.2 | 1.96 | 400 | 100 |
1.8 | 7.87 | 400 | 100 |
2.5 | 15.0 | 400 | 100 |
3.3 | 22.6 | 500 | 78.7 or open |
5 | 40.2 | 500 | 78.7 or open |
7.5 | 64.9 | 500 | 78.7 or open |
12 | 110 | 800 | 47.5 |
15 | 140 | 800 | 47.5 |
18 | 169 | 1000 | 38.3 |
20 | 191 | 1000 | 38.3 |