Shanghai ZLAN Information Technology Co., Ltd Tel: +86-17321037177 http://www.zlmcu.com
26
ZLAN1003 has two working speed: high speed and low speed.
1) High speed: pull both SPD0 and SPD1 to high level. In figure 9, the RSH resistance
is welded and the RSL resistance is not welded. At this time ZLAN1003 highest baud
rate reached 115200bps. The total required current of VCC18V is 60mA.
2) Low speed: both SPD0 and SPD1 are pulled to low level. In figure 9, the RSL
resistance is welded and the RSH resistance is not welded. At this time ZLAN1003
highest baud rate reaches 57600bps. The total required current of VCC18V is
100mA.
3.4 Use the internal 1.8V stabilized voltage supply
ZLAN1003 VCC18 power supply has two power supply modes: internal voltage regulator
generating and external power supply.
1) Internal voltage regulator generating: ZLAN1003 has a regulating circuit inside, in
VCC33VI pins enter VCC3.3 V, it produces a 1.8v power output in VCCI8O. The
VCC18O connecting with other VCC18 pins supply power to the chip. In figure 4, the
R18INNER resistance and not welding the R18OUTER, it uses internal regulator
generating type. In this way ZLAN1003 will generate additional heat due to stable
pressure. It is not recommended unless it is particularly necessary to reduce costs
and reduce volume.
2) External power supply: by default use this method. Users can convert VCC3.3V to
1.8V through an lm1117-1.8 regulating chip, and then supply to ZLAN1003. At this
time, VCC33VI and VCC180 both connect the 1.8V power supply from external
LM1117-1.8.
3.5 Reduce power consumption design
According to the above analysis, the following methods can be used to reduce the heat
of ZLAN1003:
1) External power supply: using the external lm1117-1.8 regulating chip to provide 1.8V
power supply, and the internal regulator is disabled. Because the heat dissipation of