Otp rom – ELAN Home Systems EM78P458 User Manual
Page 49
EM78P458/459
OTP ROM
3.3k
1.43 MHz
1.35 MHz
5.1k
980 KHz
877 KHz
10k
520 KHz
465 KHz
100 pF
100k
57 KHz
54 KHz
3.3k
510 KHz
470 KHz
5.1k
340 KHz
320 KHz
10k
175 KHz
170 KHz
300 pF
100k
19 KHz
19 KHz
<Note> 1. Measured on DIP packages.
2. Design reference only
4. RC Oscillator Mode with Internal Capacitor
If both precision and cost are taken into consideration, EM78P257A/B also offers a special oscillation
mode. It is equipped with an internal capacitor and an external resistor (connected to Vcc). The
internal capacitor functions as temperature compensator. In order to obtain more accurate frequency,
a precise resistor is recommended.
OSCI
EM78P458
Vcc
Rext
EM78P459
Fig. 23 Circuit for Internal C Oscillator Mode
Table 15 R Oscillator Frequencies
Rext
Average Fosc 5V,25
°C
Average Fosc 3V,25
°C
51k
2.22 MHz
2.17 MHz
100k
1.15 MHz
1.14 MHz
300k
375 KHz
370 KHz
<Note> 1. Measured on DIP packages.
2. Design reference only
This specification is subject to change without prior notice. 07.01.2003 (V1.3)
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