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參數(shù)資料
| 型號(hào)： | ADM694AN |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 電源管理 |
| 英文描述： | Microprocessor Supervisory Circuits |
| 中文描述： | 1-CHANNEL POWER SUPPLY MANAGEMENT CKT, PDIP8 |
| 封裝： | PLASTIC, DIP-8 |
| 文件頁(yè)數(shù)： | 8/16頁(yè) |
| 文件大?。?/td> | 284K |
| 代理商： | ADM694AN |
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ADM690–ADM695
REV. A
–8–
CE
Gating and RAM Write Protection (ADM691/ADM693/
ADM695)
T he ADM691/ADM693/ADM695 products include memory
protection circuitry which ensures the integrity of data in mem-
ory by preventing write operations when V
CC
is at an invalid
level. T here are two additional pins,
CE
IN
and
CE
OUT
, which
may be used to control the Chip Enable or Write inputs of
CMOS RAM. When V
CC
is present,
CE
OUT
is a buffered replica
of
CE
IN
, with a 5 ns propagation delay. When V
CC
falls below
the reset voltage threshold or V
BAT T
, an internal gate forces
CE
OUT
high, independent of
CE
IN
.
CE
OUT
typically drives the
CE
,
CS
, or write input of battery
backed up CMOS RAM. T his ensures the integrity of the data
in memory by preventing write operations when V
CC
is at an in-
valid level. Similar protection of EEPROMs can be achieved by
using the
CE
OUT
to drive the store or write inputs.
If the 5 ns typical propagation delay of
CE
OUT
is excessive, con-
nect
CE
IN
to GND and use the resulting
CE
OUT
to control a
high speed external logic gate.
ADM69x
CE
OUT
CE
IN
V
CC
LOW = 0
V
CC
OK = 1
Figure 5. Chip Enable Gating
Power Fail Warning Comparator
An additional comparator is provided for early warning of failure
in the microprocessor’s power supply. T he Power Fail Input
(PFI) is compared to an internal +1.3 V reference. T he Power
Fail Output (
PFO
) goes low when the voltage at PFI is less than
1.3 V. T ypically PFI is driven by an external voltage divider
which senses either the unregulated dc input to the system’s 5 V
regulator or the regulated 5 V output. T he voltage divider ratio
can be chosen such that the voltage at PFI falls below 1.3 V sev-
eral milliseconds before the +5 V power supply falls below the
reset threshold.
PFO
is normally used to interrupt the micropro-
cessor so that data can be stored in RAM and the shut down
procedure executed before power is lost
ADM69x
POWER
FAIL
INPUT
R
2
INPUT
POWER
1.3V
PFO
POWER
FAIL
OUTPUT
R
1
Figure 7. Power Fail Comparator
T able II. Input and Output Status In Battery Backup Mode
Signal
Status
V
OUT
V
OUT
is connected to V
BAT T
via an internal
PMOS switch.
Logic low.
Logic high. T he open circuit output voltage is
equal to V
OUT
.
Logic low.
Logic high. T he open circuit voltage is equal to
V
OUT .
WDI is ignored. It is internally disconnected
from the internal pull-up resistor and does not
source or sink current as long as its input voltage
is between GND and V
OUT
. T he input voltage
does not affect supply current.
Logic high. T he open circuit voltage is equal
to V
OUT
.
T he Power Fail Comparator is turned off and
has no effect on the Power Fail Output.
Logic low.
CE
IN
is ignored. It is internally disconnected
from its internal pull-up and does not source or
sink current as long as its input voltage is
between GND and V
OUT
. T he input voltage
does not affect supply current.
Logic high. T he open circuit voltage is equal to
V
OUT
.
OSC IN is ignored.
OSC SEL is ignored.
RESET
RESET
LOW LINE
BAT T ON
WDI
WDO
PFI
PFO
CE
IN
CE
OUT
OSC IN
OSC SEL
t
1
t
1
= RESET TIME.
V1 = RESET VOLTAGE THRESHOLD LOW
V2 = RESET VOLTAGE THRESHOLD HIGH
HYSTERESIS = V2–V1
V2
V2
V1
V1
t
1
V
CC
LOW LINE
RESET
CE
IN
CE
OUT
Figure 6. Chip Enable Timing
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ADM694AQ | Microprocessor Supervisory Circuits |
| ADM694SQ | Microprocessor Supervisory Circuits |
| ADM695AN | Microprocessor Supervisory Circuits |
| ADM695AQ | SWITCH QUAD SPST, DIP16, 271; Analogue switch type:Quad SPST; Channels, No. of:4; Resistance, Rds on:50R; Temp, op. max:70(degree C); Temp, op. min:0(degree C); Pins, No. of:16; Case style:DIP; Base number:271; IC Generic number:271; RoHS Compliant: Yes |
| ADM695AR | Analog Switch / Multiplexer (Mux) IC; Analog Switch Function:High-Speed; Package/Case:16-SOIC; Leaded Process Compatible:Yes; Leakage Current:1nA; On Resistance, Rds(on):50ohm; Peak Reflow Compatible (260 C):Yes RoHS Compliant: Yes |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ADM694ANZ | 功能描述:IC SUPER MPU 4.65 100MA 8DIP RoHS:是 類別:集成電路 (IC) >> PMIC - 監(jiān)控器 系列:- 標(biāo)準(zhǔn)包裝:100 系列:- 類型:簡(jiǎn)單復(fù)位/加電復(fù)位 監(jiān)視電壓數(shù)目:1 輸出:開路漏極，開路漏極 復(fù)位:高有效/低有效 復(fù)位超時(shí):最小為 250 ms 電壓 - 閥值:4.37V，4.62V 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 供應(yīng)商設(shè)備封裝:8-SOIC 包裝:管件 產(chǎn)品目錄頁(yè)面:1337 (CN2011-ZH PDF) |
| ADM694ANZ | 制造商:Analog Devices 功能描述:IC SUPERVISORY CIRCUIT |
| ADM694AQ | 制造商:AD 制造商全稱:Analog Devices 功能描述:Microprocessor Supervisory Circuits |
| ADM694SQ | 功能描述:IC SUPERVISOR MPU 4.65V 8CDIP RoHS:否 類別:集成電路 (IC) >> PMIC - 監(jiān)控器 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 類型:簡(jiǎn)單復(fù)位/加電復(fù)位 監(jiān)視電壓數(shù)目:1 輸出:開路漏極或開路集電極 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 安裝類型:表面貼裝 封裝/外殼:6-TSOP（0.059"，1.50mm 寬）5 引線 供應(yīng)商設(shè)備封裝:5-TSOP 包裝:剪切帶 (CT) 其它名稱:NCP301HSN18T1GOSCT |
| ADM695 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Microprocessor Supervisory Circuits |
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