參數(shù)資料
型號(hào)： ADM8690
廠商： Analog Devices, Inc.
英文描述： Microprocessor Supervisory Circuits(微處理器監(jiān)控電路)
中文描述： 微處理器監(jiān)控電路（微處理器監(jiān)控電路）
文件頁(yè)數(shù)： 5/16頁(yè)
文件大?。?/td> 183K
代理商： ADM8690
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(guān)PDF資料
PDF描述
ADM8690ADM8695 Microprocessor Supervisory Circuits
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
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ADM8690ADM8695 制造商:AD 制造商全稱(chēng):Analog Devices 功能描述:Microprocessor Supervisory Circuits
ADM8690-ADM8695 制造商:AD 制造商全稱(chēng):Analog Devices 功能描述:Microprocessor Supervisory Circuits
ADM8690AN 功能描述:IC SUPERVISOR MPU 4.65V 8DIP RoHS:否 類(lèi)別:集成電路 (IC) >> PMIC - 監(jiān)控器 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 類(lèi)型:簡(jiǎn)單復(fù)位/加電復(fù)位 監(jiān)視電壓數(shù)目:1 輸出:開(kāi)路漏極或開(kāi)路集電極 復(fù)位:高有效 復(fù)位超時(shí):- 電壓 - 閥值:1.8V 工作溫度:-40°C ~ 125°C 安裝類(lèi)型:表面貼裝 封裝/外殼:6-TSOP（0.059"，1.50mm 寬）5 引線(xiàn) 供應(yīng)商設(shè)備封裝:5-TSOP 包裝:剪切帶 (CT) 其它名稱(chēng):NCP301HSN18T1GOSCT
ADM8690ANZ 功能描述:IC SUPERVISOR MPU 4.65V 8DIP RoHS:是 類(lèi)別:集成電路 (IC) >> PMIC - 監(jiān)控器 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 類(lèi)型:簡(jiǎn)單復(fù)位/加電復(fù)位 監(jiān)視電壓數(shù)目:1 輸出:開(kāi)路漏極或開(kāi)路集電極 復(fù)位:高有效 復(fù)位超時(shí):- 電壓 - 閥值:1.8V 工作溫度:-40°C ~ 125°C 安裝類(lèi)型:表面貼裝 封裝/外殼:6-TSOP（0.059"，1.50mm 寬）5 引線(xiàn) 供應(yīng)商設(shè)備封裝:5-TSOP 包裝:剪切帶 (CT) 其它名稱(chēng):NCP301HSN18T1GOSCT
ADM8690ARN 功能描述:IC SUPERVISOR MPU 4.65V 8SOIC RoHS:否 類(lèi)別:集成電路 (IC) >> PMIC - 監(jiān)控器 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 類(lèi)型:簡(jiǎn)單復(fù)位/加電復(fù)位 監(jiān)視電壓數(shù)目:1 輸出:開(kāi)路漏極或開(kāi)路集電極 復(fù)位:高有效 復(fù)位超時(shí):- 電壓 - 閥值:1.8V 工作溫度:-40°C ~ 125°C 安裝類(lèi)型:表面貼裝 封裝/外殼:6-TSOP（0.059"，1.50mm 寬）5 引線(xiàn) 供應(yīng)商設(shè)備封裝:5-TSOP 包裝:剪切帶 (CT) 其它名稱(chēng):NCP301HSN18T1GOSCT
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