![](http://datasheet.mmic.net.cn/330000/MB90F598_datasheet_16438024/MB90F598_13.png)
MB90595/595G Series
13
(5) Pull-up/down resistors
The MB90595 Series does not support internal pull-up/down resistors. Use external components where needed.
(6) Crystal Oscillator Circuit
Noises around X0 or X1 pins may cause abnormal operations. Make sure to provide bypass capacitors via
shortest distance from X0, X1 pins, crystal oscillator (or ceramic resonator) and ground lines, and make sure
that lines of oscillation circuit not cross the lines of other circuits.
A printed circuit board artwork surrounding the X0 and X1 pins with ground area for stabilizing the operation is
highly recommended.
(7) Turning-on Sequence of Power Supply to A/D Converter and Analog Inputs
Make sure to turn on the A/D converter power supply (AV
CC
, AVRH, AVRL) and analog inputs (AN0 to AN7)
after turning-on the digital power supply (V
CC
).
Turn-off the digital power after turning off the A/D converter supply and analog inputs. In this case, make sure
that the voltage does not exceed AVRH or AV
CC
(turning on/off the analog and digital power supplies simulta-
neously is acceptable).
(8) Connection of Unused Pins of A/D Converter
Connect unused pins of A/D converter to AV
CC
= V
CC
, AV
SS
= AVRH = DV
CC
= V
SS
.
(9) N.C. Pin
The N.C. (internally connected) pin must be opened for use.
(10) Notes on Energization
To prevent the internal regulator circuit from malfunctioning, set the voltage rise time during energization at 50
μ
s or more (0.2 V to 2.7 V).
(11) Indeterminate outputs from ports 0 and 1
During oscillation setting time of step-down circuit (during a power-on reset) after the power is turned on, the
outputs from ports 0 and 1 become following state.
If RST pin is “H”, the outputs become indeterminate.
If RST pin is “L”, the outputs become high-impedance.
Pay attention to the port output timing shown as follow.
Oscillation setting time
2
Power-on reset
1
Vcc (Power-supply pin)
PONR (power-on reset) signal
RST (external asynchronous reset) signal
RST (internal reset) signal
Oscillation clock signal
KA (internal operation clock A) signal
KB (internal operation clock B) signal
PORT (port output) signal
Period of indeterminated
*1:Power-on reset time: Period of “clock frequency
×
2
17
” (Clock frequency of 16 MHz: 8.19 ms)
*2:Oscillation setting time: Period of “clock frequency
×
2
18
” (Clock frequency of 16 MHz: 16.38ms)
RST pin is “H”