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參數資料
| 型號： | ADM8690ADM8695 |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | Microprocessor Supervisory Circuits |
| 中文描述： | 微處理器監控電路 |
| 文件頁數： | 5/16頁 |
| 文件大小： | 183K |
| 代理商： | ADM8690ADM8695 |
ADM8690–ADM8695
REV. 0
–5–
PIN CONFIGURAT IONS
1
2
3
4
8
7
6
5
TOP VIEW
(Not to Scale)
ADM8690
ADM8692
ADM8694
V
OUT
PFO
WDI
RESET
V
BATT
V
CC
GND
PFI
14
13
12
11
16
15
10
9
8
1
2
3
4
7
6
5
TOP VIEW
(Not to Scale)
ADM8691
ADM8693
ADM8695
V
BATT
CE
IN
WDO
RESET
RESET
V
OUT
V
CC
GND
PFO
WDI
CE
OUT
BATT ON
LOW LINE
OSC IN
OSC SEL
PFI
CIRCUIT INFORMAT ION
Battery Switchover Section
T he battery switchover circuit compares V
CC
to the V
BAT T
input, and connects V
OUT
to whichever is higher. Switchover
occurs when V
CC
is 50 mV higher than V
BAT T
as V
CC
falls, and
when V
CC
is 70 mV greater than V
BAT T
as V
CC
rises. T his
20 mV of hysteresis prevents repeated rapid switching if V
CC
falls very slowly or remains nearly equal to the battery voltage.
V
CC
V
BATT
V
OUT
BATT ON
(ADM8690,
ADM8695)
100
mV
700
mV
INTERNAL
SHUTDOWN SIGNAL
WHEN
V
BATT
> (V
CC
+ 0.7V)
GATE DRIVE
Figure 1. Battery Switchover Schematic
During normal operation, with V
CC
higher than V
BAT T
, V
CC
is
internally switched to V
OUT
via an internal PMOS transistor
switch. T his switch has a typical on-resistance of 0.7
and can
supply up to 100 mA at the V
OUT
terminal. V
OUT
is normally
used to drive a RAM memory bank which may require instanta-
neous currents of greater than 100 mA. If this is the case then a
bypass capacitor should be connected to V
OUT
. T he capacitor
will provide the peak current transients to the RAM. A capaci-
tance value of 0.1
μ
F or greater may be used.
If the continuous output current requirement at V
OUT
exceeds
100 mA, or if a lower V
CC
–V
OUT
voltage differential is desired,
an external PNP pass transistor may be connected in parallel with
the internal transistor. T he BAT T ON output (ADM8691/
ADM8693/ADM8695) can directly drive the base of the exter-
nal transistor.
A 7
MOSFET switch connects the V
BAT T
input to V
OUT
dur-
ing battery backup. T his MOSFET has very low input-to-out-
put differential (dropout voltage) at the low current levels
required for battery back up of CMOS RAM or other low power
CMOS circuitry. T he supply current in battery back up is typi-
cally 0.4
μ
A.
T he ADM8690/ADM8691/ADM8694/ADM8695 operates with
battery voltages from 2.0 V to 4.25 V, and the ADM8692/
ADM8693 operates with battery voltages from 2.0 V to 4.0 V.
High value capacitors, either standard electrolytic or the farad
size double layer capacitors, can also be used for short-term
memory backup. A small charging current of typically 10 nA
(0.1
μ
A max) flows out of the V
BAT T
terminal. T his current is
useful for maintaining rechargeable batteries in a fully charged
condition. T his extends the life of the backup battery by com-
pensating for its self discharge current. Also note that this cur-
rent poses no problem when lithium batteries are used for
backup since the maximum charging current (0.1
μ
A) is safe for
even the smallest lithium cells.
If the battery switchover section is not used, V
BAT T
should be
connected to GND and V
OUT
should be connected to V
CC
.
PRODUCT SE LE CT ION GUIDE
Part
Number
Nominal Reset
T ime
Nominal V
CC
Reset T hreshold
Nominal Watchdog
T imeout Period
Battery Backup
Switching
Base Drive
E xt PNP
Chip E nable
Signals
ADM8690
ADM8691
ADM8692
ADM8693
ADM8694
ADM8695
50 ms
50 ms or ADJ
50 ms
50 ms or ADJ
200 ms
200 ms or ADJ
4.65 V
4.65 V
4.4 V
4.4 V
4.65 V
4.65 V
1.6 s
100 ms, 1.6 s, ADJ
1.6 s
100 ms, 1.6 s, ADJ
1.6 s
100 ms, 1.6 s, ADJ
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
相關PDF資料 |
PDF描述 |
|---|---|
| ADM8691ARN | Microprocessor Supervisory Circuits |
| ADM8691ARU | Microprocessor Supervisory Circuits |
| ADM8691ARW | Microprocessor Supervisory Circuits |
| ADM8693ARN | Thyristor Module; Current, It av:250A; Repetitive Reverse Voltage Max, Vrrm:1600V; Peak Surge Current:8800A; di/dt:800A/ s; Package/Case:ND44; Peak Reflow Compatible (260 C):Yes; Current Rating:250A |
| ADM8693ARU | Thyristor Diode Module; Repetitive Reverse Voltage Max, Vrrm:1800V; Leaded Process Compatible:Yes; Voltage Rating:1800V RoHS Compliant: Yes |
相關代理商/技術參數 |
參數描述 |
|---|---|
| ADM8690-ADM8695 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Microprocessor Supervisory Circuits |
| ADM8690AN | 功能描述:IC SUPERVISOR MPU 4.65V 8DIP RoHS:否 類別:集成電路 (IC) >> PMIC - 監控器 系列:- 標準包裝:1 系列:- 類型:簡單復位/加電復位 監視電壓數目:1 輸出:開路漏極或開路集電極 復位:高有效 復位超時:- 電壓 - 閥值:1.8V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:6-TSOP（0.059"，1.50mm 寬）5 引線 供應商設備封裝:5-TSOP 包裝:剪切帶 (CT) 其它名稱:NCP301HSN18T1GOSCT |
| ADM8690ANZ | 功能描述:IC SUPERVISOR MPU 4.65V 8DIP RoHS:是 類別:集成電路 (IC) >> PMIC - 監控器 系列:- 標準包裝:1 系列:- 類型:簡單復位/加電復位 監視電壓數目:1 輸出:開路漏極或開路集電極 復位:高有效 復位超時:- 電壓 - 閥值:1.8V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:6-TSOP（0.059"，1.50mm 寬）5 引線 供應商設備封裝:5-TSOP 包裝:剪切帶 (CT) 其它名稱:NCP301HSN18T1GOSCT |
| ADM8690ARN | 功能描述:IC SUPERVISOR MPU 4.65V 8SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 監控器 系列:- 標準包裝:1 系列:- 類型:簡單復位/加電復位 監視電壓數目:1 輸出:開路漏極或開路集電極 復位:高有效 復位超時:- 電壓 - 閥值:1.8V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:6-TSOP（0.059"，1.50mm 寬）5 引線 供應商設備封裝:5-TSOP 包裝:剪切帶 (CT) 其它名稱:NCP301HSN18T1GOSCT |
| ADM8690ARN-REEL | 功能描述:IC SUPERVISOR MPU 4.65V 8SOIC TR RoHS:否 類別:集成電路 (IC) >> PMIC - 監控器 系列:- 標準包裝:1 系列:- 類型:簡單復位/加電復位 監視電壓數目:1 輸出:開路漏極或開路集電極 復位:高有效 復位超時:- 電壓 - 閥值:1.8V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:6-TSOP（0.059"，1.50mm 寬）5 引線 供應商設備封裝:5-TSOP 包裝:剪切帶 (CT) 其它名稱:NCP301HSN18T1GOSCT |
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