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參數(shù)資料
| 型號： | LTC692 |
| 廠商： | Linear Technology Corporation |
| 英文描述： | Microprocessor Supervisory Circuits(μP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） |
| 文件頁數(shù)： | 8/16頁 |
| 文件大?。?/td> | 261K |
| 代理商： | LTC692 |
8
LTC692/LTC693
Microprocessor Reset
The LTC692/LTC693 use a bandgap voltage reference and
a precision voltage comparator C1 to monitor the 5V
supply input on V
CC
(see BLOCK DIAGRAM). When V
CC
falls below the reset voltage threshold, the RESET output
is forced to active low state. The reset voltage threshold
accounts for a 10% variation on V
CC
, so the RESET output
becomes active low when V
CC
falls below 4.50V (4.40V
typical). On power-up, the RESET signal is held active low
for a minimum of 140ms after reset voltage threshold is
reached to allow the power supply and microprocessor to
stabilize. The reset active time is adjustable on the LTC693.
On power-down, the RESET signal remains active low
even with V
CC
as low as 1V. This capability helps hold the
microprocessor in stable shutdown condition. Figure 1
shows the timing diagram of the RESET signal.
The precision voltage comparator, C1, typically has 40mV
of hysteresis which ensures that glitches at the V
CC
pin do
not activate the RESET output. Response time is typically
10
μ
s. To help prevent mistriggering due to transient loads,
V
CC
pin should be bypassed with a 0.1
μ
F capacitor with the
leads trimmed as short as possible.
The LTC693 has two additional outputs: RESET and LOW
LINE. RESET is an active high output and is the inverse of
RESET. LOW LINE is the output of the precision voltage
comparator C1. When V
CC
falls below the reset voltage
threshold, LOW LINE goes low. LOW LINE returns high as
soon as V
CC
rises above the reset voltage threshold.
Battery Switchover
The battery switchover circuit compares V
CC
to the
V
BATT
input, and connects V
OUT
to whichever is higher.
When V
CC
rises to 70mV above V
BATT
, the battery
switchover comparator, C2, connects V
OUT
to V
CC
through
a charge pumped NMOS power switch, M1. When V
CC
falls to 50mV above V
BATT
, C2 connects V
OUT
to V
BATT
through a PMOS switch, M2. C2 has typically 20mV of
hysteresis to prevent spurious switching when V
CC
remains nearly equal to V
BATT
. The response time of C2
is approximately 20
μ
s.
During normal operation, the LTC692/LTC693 use a charge
pumped NMOS power switch to achieve low dropout and
low supply current. This power switch can deliver up to
50mA to V
OUT
from V
CC
and has a typical “on” resistance
of 5
. The V
OUT
pin should be bypassed with a capacitor
of 0.1
μ
F or greater to ensure stability. Use of a larger
bypass capacitor is advantageous for supplying current to
heavy transient loads.
When operating currents larger than 50mA are required
from V
OUT
, or a lower dropout (V
CC
– V
OUT
voltage differ-
ential) is desired, the LTC693 should be used. This prod-
uct provides BATT ON output to drive the base of the
external PNP transistor (Figure 2). If higher currents are
needed with the LTC692, a high current Schottky diode
can be connected from the V
CC
pin to the V
OUT
pin to
supply the extra current.
U
S
A
O
PPLICATI
U
U
V
CC
t1
t1 = RESET ACTIVE TIME
V1 = RESET VOLTAGE THRESHOLD
V2 = RESET VOLTAGE THRESHOLD +
RESET THRESHOLD HYSTERESIS
t1
V2
V2
V1
V1
LTC692/3 F01
RESET
LOW LINE
Figure 1. Reset Active Time
相關PDF資料 |
PDF描述 |
|---|---|
| LTC693 | Microprocessor Supervisory Circuits(μP監(jiān)控電路) |
| LTC694-3.3 | 3.3V Microprocessor Supervisory Circuits(3.3VμP監(jiān)控電路) |
| LTC695CSW-3.3 | 3.3V Microprocessor Supervisory Circuits |
| LTC695 | Microprocessor Supervisory Circuits |
| LTC695-3.3 | 3.3V Microprocessor Supervisory Circuits |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LTC692_09 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Microprocessor Supervisory Circuits |
| LTC692C | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Microprocessor Supervisory Circuits |
| LTC692CN8 | 功能描述:IC MPU SUPERVISORY CIRCUIT 8-DIP RoHS:否 類別:集成電路 (IC) >> PMIC - 監(jiān)控器 系列:- 標準包裝:1 系列:- 類型:簡單復位/加電復位 監(jiān)視電壓數(shù)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 |
| LTC692CN8#PBF | 功能描述:IC MPU SUPERVISORY CIRCUIT 8-DIP RoHS:是 類別:集成電路 (IC) >> PMIC - 監(jiān)控器 系列:- 標準包裝:1 系列:- 類型:簡單復位/加電復位 監(jiān)視電壓數(shù)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 |
| LTC692CN8-PBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Microprocessor Supervisory Circuits |
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