UC3845 and UC2845BN cannot be substituted. Their starting voltage and cut-off voltage are different. The replacement may be fine but it will cause problems during normal operation.UC3845B Main use: charge control circuit, the integrated block adopts 8-pin package, power supply: 7-pin 12V.UC2845BN: pwm controller power chip. Input voltage 15V; Output voltage :5V; Output current 200mA; Minimum power supply voltage 12V; Maximum power supply voltage 25V; Controller chip package type dip; Number of stitches 8; Frequency 250kHz; Minimum operating temperature -40°C; Maximum operating temperature 150°C.
The operating temperature is different
The difference between uc2845 and uc3845 is that the operating temperature is different.
The UC2845 operates at -40 °C to 85°C, while the UC3845 operates at 0°C to 70°C. The IC at the beginning of UC28xx is an industrial grade collector circuit, and the IC at the beginning of UC3XX is a civil grade integrated circuit. The temperature range of the industrial grade is relatively wide, and it can work normally at low temperatures, and the parameters are the same. Therefore, when the requirements are different, such as the low temperature in the north,UC3845 can not directly replace UC2845.