ADUC7025BCPZ32-RL7 AD [Analog Devices], ADUC7025BCPZ32-RL7 Datasheet - Page 85

• Manufacturer Part Number: ADUC7025BCPZ32-RL7
• Description: Precision Analog Microcontroller 12-bit Analog I/O, ARM7TDMI MCU
• Manufacturer: AD [Analog Devices]

POWER-ON RESET OPERATION
An internal power-on reset (POR) is implemented on the
ADuC7019/7020/7021/7022/7024/7025/7026/7027. For LV
below 2.35 V typical, the internal POR holds the part in reset.
As LV
typically 128 ms before the part is released from reset. The user
must ensure that the power supply IOV
2.7 V minimum level by this time. Likewise, on power-down,
the internal POR holds the ADuC7019/7020/7021/7022/
7024/7025/7026/7027 in reset until LV
2.35 V.
Figure 79 illustrates the operation of the internal POR in detail.
TYPICAL SYSTEM CONFIGURATION
A typical ADuC7020 configuration is shown in Figure 80. It summarizes some of the hardware considerations discussed in the previous
sections. The bottom of the CSP package has an exposed pad that needs to be soldered to a metal plate on the board for mechanical
reasons. The metal plate of the board can be connected to ground.
1kΩ
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
DD
DV
DD
rises above 2.35 V, an internal timer times out for
+
–
TRST
TDI
TMS
TCK
TDO
DV
DD
DV
10Ω
DD
0.01μF
10
1
2
3
4
5
6
7
8
9
GND
DAC0
TMS
TDI
P0.0
40
11
39
12
REF
38
13
AV
ADuC7020
DD
37
14
DD
DD
has dropped below
36
15
has reached a stable
0.47μF
DV
0.47μF
35
16
DD
34
17
33
18
Figure 80. Typical System Configuration
XCLKO
32
XCLKI
19
31
20
DD
30
29
28
27
26
25
24
23
22
21
Rev. A | Page 85 of 92
DV
DD
1kΩ
32.768kHz
RS232 INTERFACE*
* EXTERNAL UART TRANSCEIVER INTEGRATED IN SYSTEM OR AS
PART OF AN EXTERNAL DONGLE AS DESCRIBED IN uC006.
AV
DD
Figure 79. ADuC7019/7020/7021/7022/7024/7025/7026/7027
10μF
1.5Ω
IOV
MRST
LV
POR
DD
DD
ADuC7019/20/21/22/24/25/26/27
2.35V TYP
1
2
3
4
5
6
7
8
270Ω
C1+
V+
C1–
C2+
C2–
V–
T2OUT
R2IN
ADM3202
Internal Power-on Reset Operation
DV
DD
10μF
R1OUT
R2OUT
T1OUT
GND
R1IN
T1IN
T2IN
V
CC
NOT CONNECTED IN THIS EXAMPLE
ADP3333-3.3
128ms TYP
16
15
14
13
12
11
10
9
OUT
GND
0.12ms TYP
SD
IN
3.3V
2.6V
0.1μF
STANDARD D-TYPE
2.35V TYP
CONNECTOR TO
SERIAL COMMS
PC HOST
1
2
3
4
5
6
7
8
9