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參數資料
| 型號： | ADM811 |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | Battery Back-up Supervisor for Dual SRAM Banks 16-TSSOP -20 to 70 |
| 中文描述： | 微處理器監控電路4引腳SOT - 143 |
| 文件頁數： | 5/6頁 |
| 文件大小： | 83K |
| 代理商： | ADM811 |
ADM811/ADM812
–5–
REV. 0
CIRCUIT INFORMATION
RESET THRESHOLDS
The reset output provides a
RESET
(for the ADM811) or a
RESET (for the ADM812) output to the microprocessor when-
ever the V
CC
input is below the reset threshold. The actual reset
threshold is dependant on whether a L, M, T, S or R suffix is
used. Please refer to Table I.
Table I. Reset Threshold Options
RESET
Threshold
Model
ADM811LART
ADM811MART
ADM811TART
ADM811-3TART
ADM811SART
ADM811RART
ADM812LART
ADM812MART
ADM812TART
ADM812SART
ADM812RART
4.63 V
4.38 V
3.08 V
3.08 V
2.93 V
2.63 V
4.63 V
4.38 V
3.08 V
2.93 V
2.63 V
Parts in bold type are ex-stock, please contact factory for availability.
RESET OUTPUT
On power-up and after V
CC
rises above the reset threshold, an
internal timer holds the reset output active for 240 ms (typical).
This is intended as a power-on reset signal for the processor. It
allows time for both the power supply and the microprocessor
to stabilize after power-up. If a power supply brownout or inter-
ruption occurs, the reset output is similarly activated and re-
mains active for 240 ms (typical) after the supply recovers. This
allows time for the power supply and microprocessor to stabilize.
The ADM811 provides an active low reset output (
RESET
)
while the ADM812 provides an active high output (RESET).
During power-down of the ADM811, the
RESET
output re-
mains valid (low) with V
CC
as low as 1 V. This ensures that the
microprocessor is held in a stable shutdown condition as the
supply falls and also ensures that no spurious activity can occur
via the
μ
P as it powers up.
MANUAL RESET
The ADM811/ADM812 is equipped with a manual reset input.
This input is designed to operate in a noisy environment where
unwanted glitches could be induced. These glitches could be
produced by the bouncing action of a switch contact or where a
Manual Reset switch may be located some distance away from
the circuit (the cabling of which may pickup noise).
The Manual Reset input is guaranteed to ignore logically valid
inputs which are faster than 100 ns and accept inputs longer in
duration than 10
μ
s.
GLITCH IMMUNITY
The ADM811/ADM812 contain internal filtering circuitry
providing glitch immunity from fast transient glitches on the
power supply line.
RESET
V
REF
V
REF
V
REF
V
REF
t
1
t
1
V
CC
t
1
=
RESET
TIME = 240ms TYPICAL
V
REF
=
RESET
VOLTAGE THRESHOLD
Figure 8. Power Fail
RESET
Timing
INTERFACING TO OTHER DEVICES
Output
The ADM811/ADM812 series is designed to integrate with
as many devices as possible. One feature of the ADM811/
ADM812 is the reset output, which is directly proportional to
V
CC
(this is guaranteed only while V
CC
is greater than 1 V). This
enables the part to be used in both 3 V and 5 V or any nominal
voltage within the minimum and maximum specifications for V
CC
.
THE BENEFITS OF A VERY ACCURATE RESET
THRESHOLD
Because the ADM811/ADM812 series can operate effectively
even when there are large degradations of the supply voltages,
the possibility of a malfunction during a power failure is greatly
reduced. Another advantage of the ADM811/ADM812 series is
its very accurate internal voltage reference circuit. Combined,
these benefits produce an exceptionally reliable Microprocessor
Supervisory Circuit.
V
CC
RESET
ADM811
GND
V
CC
Figure 9. Ensuring a Valid
RESET
Output Down to
V
CC
= 0 V
ENSURING A VALID RESET OUTPUT DOWN TO
V
CC
= 0 V
When V
CC
falls below 0.8 V, ADM811s
RESET
no longer sinks
current. Therefore, a high impedance CMOS logic input con-
nected to RESET may drift to undetermined logic levels. To
eliminate this problem a 100 k
resistor should be connected
from
RESET
to ground.
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| ADM811-3TART-REEL | Microprocessors Supervisory Circuit in 4-Lead SOT-143 |
| ADM811-3TART-RL7 | Microprocessors Supervisory Circuit in 4-Lead SOT-143 |
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相關代理商/技術參數 |
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|---|---|
| ADM811-3TART | 制造商:AD 制造商全稱:Analog Devices 功能描述:Microprocessor Supervisory Circuit in 4-Lead SOT-143 with DSP |
| adm811-3tart-reel | 制造商:Analog Devices 功能描述:300MSEC TIMEOUT I.C. - Tape and Reel |
| ADM811-3TART-REEL7 | 功能描述:IC SUPERVSR W/RESET 3.08V SOT143 RoHS:否 類別:集成電路 (IC) >> PMIC - 監控器 系列:- 標準包裝:400 系列:- 類型:備用電池電路 監視電壓數目:1 輸出:開路漏極，推挽式 復位:高有效/低有效 復位超時:最小為 35 ms 電壓 - 閥值:4.65V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:16-SOIC（0.295"，7.50mm 寬） 供應商設備封裝:16-SOIC W 包裝:帶卷 (TR) 其它名稱:ADM691ARZ-REEL7TR |
| ADM811-3TART-RL7 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Microprocessors Supervisory Circuit in 4-Lead SOT-143 |
| ADM811-3TARTZ-RL | 功能描述:IC SUPERVISOR RESET 3.08V SOT143 RoHS:是 類別:集成電路 (IC) >> PMIC - 監控器 系列:- 標準包裝:3,000 系列:- 類型:簡單復位/加電復位 監視電壓數目:1 輸出:推挽式，圖騰柱 復位:高有效 復位超時:最小為 100 ms 電壓 - 閥值:3.06V 工作溫度:-40°C ~ 105°C 安裝類型:表面貼裝 封裝/外殼:SC-70，SOT-323 供應商設備封裝:SC-70-3 包裝:帶卷 (TR) 其它名稱:ADM1817-5AKSREEL7 |
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