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參數(shù)資料
| 型號(hào)： | LTC2900-2CMS |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 電源管理 |
| 英文描述： | Programmable Quad Supply Monitor with Adjustable Reset Timer |
| 中文描述： | 4-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO10 |
| 封裝： | PLASTIC, MSOP-10 |
| 文件頁數(shù)： | 11/16頁 |
| 文件大?。?/td> | 199K |
| 代理商： | LTC2900-2CMS |
11
LTC2900
2900f
APPLICATIOU
Although all four supply monitor comparators have built-
in glitch immunity, bypass capacitors on V1 and V2 are
recommended because the greater of V1 or V2 is also the
V
CC
for the device. Filter capacitors on the V3 and V4
inputs are allowed.
W
U
U
Power-Down
On power-down, once any of the V
X
inputs drop below
their threshold, RST is held at a logic low. A logic low of
0.4V is guaranteed until both V1 and V2 drop below 1V. If
the bandgap reference becomes invalid (V
CC
< 2V typ), the
part will reprogram once V
CC
rises above 2.4V max.
Monitor Output Rise and Fall Time Estimation
The RST output has strong pull-down capability. If the
external load capacitance (C
LOAD
) is known, output fall
time (10% to 90%) is estimated using:
t
FALL
≈
2.2 R
PD
C
LOAD
where R
PD
is the on-resistance of the internal pull-down
transistor. The typical performance curve (V
OL
vs I
SINK
)
demonstrates that the pull-down current is somewhat
linear versus output voltage. Using the 25
°
C curve, R
PD
is
estimated to be approximately 40
. Assuming a 150pF
load capacitance, the fall time is about 13.2ns.
Although the RST output of the LTC2900-1 is considered
to be “open-drain,” it does have weak pull-up capability
(see RST Pull-Up Current vs V2 curve). Output rise time
(10% to 90%) is estimated using:
t
RISE
≈
2.2 R
PU
C
LOAD
where R
PU
is the on-resistance of the pull-up transistor.
The on-resistance as a function of the V2 voltage at room
temperature is estimated using:
R
V
PU
=
6 10
2 1
5
–
with V2 = 3.3V, R
PU
is about 260k. Using 150pF for load
capacitance, the rise time is 86
μ
s. If the output needs to
pull up faster and/or to a higher voltage, a smaller
external pull-up resistor may be used. Using a 10k pull-
up resistor, the rise time is reduced to 3.3
μ
s for a 150pF
load capacitance.
The LTC2900-2 has an active pull-up to V2 on the RST
output. The typical performance curve (RST Pull-Up Cur-
rent vs V2 curve) demonstrates that the pull-up current is
somewhat linear versus the V2 voltage and R
PU
is esti-
mated to be approximately 625
. A 150pF load capaci-
tance makes the rise time about 206ns.
Selecting the Reset Timing Capacitor
The reset time-out period is adjustable in order to accom-
modate a variety of microprocessor applications. The
reset time-out period, t
RST
, is adjusted by connecting a
capacitor, C
RT
, between the CRT pin and ground. The value
of this capacitor is determined by:
C
RT
= t
RST
217 10
–9
with C
RT
in Farads and t
RST
in seconds. The C
RT
value per
millisecond of delay can also be expressed as C
RT
/ms =
217 (pF/ms).
Leaving the CRT pin unconnected will generate a mini-
mum reset time-out of approximately 50
μ
s. Maximum
reset time-out is limited by the largest available low
leakage capacitor. The accuracy of the time-out period will
be affected by capacitor leakage (the nominal charging
current is 2
μ
A) and capacitor tolerance. A low leakage
ceramic capacitor is recommended.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC2900-2CMS#PBF | 功能描述:IC MON SUPP QUAD PUSHPULL 10MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 監(jiān)控器 系列:- 標(biāo)準(zhǔn)包裝:400 系列:- 類型:備用電池電路 監(jiān)視電壓數(shù)目:1 輸出:開路漏極，推挽式 復(fù)位:高有效/低有效 復(fù)位超時(shí):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(yīng)商設(shè)備封裝:16-SOIC W 包裝:帶卷 (TR) 其它名稱:ADM691ARZ-REEL7TR |
| LTC2900-2CMS#PBF | 制造商:Linear Technology 功能描述:SUPPLY MONITOR, QUAD, ADJ, 43UA, MSOP-10 |
| LTC2900-2CMS#TR | 功能描述:IC MONITOR SUPPLY QUAD 10-MSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 監(jiān)控器 系列:- 標(biāo)準(zhǔn)包裝:400 系列:- 類型:備用電池電路 監(jiān)視電壓數(shù)目:1 輸出:開路漏極，推挽式 復(fù)位:高有效/低有效 復(fù)位超時(shí):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(yīng)商設(shè)備封裝:16-SOIC W 包裝:帶卷 (TR) 其它名稱:ADM691ARZ-REEL7TR |
| LTC2900-2CMS#TRPBF | 功能描述:IC MON SUPP QUAD PUSHPULL 10MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 監(jiān)控器 系列:- 標(biāo)準(zhǔn)包裝:400 系列:- 類型:備用電池電路 監(jiān)視電壓數(shù)目:1 輸出:開路漏極，推挽式 復(fù)位:高有效/低有效 復(fù)位超時(shí):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(yīng)商設(shè)備封裝:16-SOIC W 包裝:帶卷 (TR) 其它名稱:ADM691ARZ-REEL7TR |
| LTC2900-2IDD | 功能描述:IC MONITOR SUPPLY QUAD 10-DFN 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 |
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