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參數(shù)資料
| 型號： | MIC1557 |
| 廠商： | Micrel Semiconductor,Inc. |
| 英文描述： | IttyBitty RC Oscillator(IttyBitty技術CMOS RC振蕩器) |
| 中文描述： | IttyBitty RC振蕩器（IttyBitty技術的CMOS鋼筋混凝土振蕩器） |
| 文件頁數(shù)： | 5/8頁 |
| 文件大?。?/td> | 166K |
| 代理商： | MIC1557 |
October 1998
5
MIC1555/1557
MIC1555/1557
Functional Diagrams
Micrel
Functional Description
Refer to the block diagrams.
The MIC1555/7 provides the logic for creating simple RC
timer or oscillator circuits.
The MIC1555 has separate THR (threshold) and TRG
(trigger) connections for monostable (one-shot) or astable
(oscillator) operation.
The MIC1557 has a single T/T (threshold and trigger) con-
nection for astable (oscillator) operation only. The MIC1557
includes a CS (chip select/reset) control.
Supply
VS (supply) is rated for +2.7V to +18V. An external capacitor
is recommended to decouple noise.
Resistive Divider
The resistive voltage divider is constructed of three equal
value resistors to produce
1
3
V
S
and
2
3
V
S
voltage for trigger
and threshold reference voltages.
Chip Select/Reset (MIC1557 only)
CS (chip select/reset) controls the bias supply to the oscillator’s
internal circuitry. CS must be connected to CMOS logic-high
or logic-low levels. Floating CS will result in unpredictable
operation. When the chip is deselected, the supply current is
less than 1
μ
A. Forcing CS low resets the MIC1557 by setting
the flip flop, forcing the output low.
Threshold Comparator
The threshold comparator is connected to S (set) on the RS
flip-flop. When the threshold voltage (
2
3
V
S
) is reached, the
flip-flop is set, making the output low. THR is dominant over
TRG.
S
R
Q
T/T
OUT
VS
Bias
GND
CS
V
SUPPLY
MIC1557
Output
1k
0.1μF
8kHz
1M
MIC1557 Block Diagram with External Components
(Astable Configuration)
S
R
Q
OUT
GND
Output
TRG
THR
Trigger
VS
V
SUPPLY
MIC1555
1k
0.1μF
<100μs
Bias
100μs
MIC1555 Block Diagram with External Components
(Monostable Configuration)
Trigger Comparator
The trigger comparator is connected to R (reset) on the RS
flip-flop. When TRG (trigger) goes below the trigger voltage
(
1
3
V
S
), the flip-flop resets, making the output high.
Flip-Flop and Output
A reset signal causes Q to go low, turning on the P-channel
MOSFET and turning off the N-channel MOSFET. This
makes the output rise to nearly V
S
.
A set signal causes Q to go high, turning off the P-channel
MOSFET, and turning on the N-channel MOSFET, grounding
OUT.
Basic Monostable Operation
Refer to the MIC1555 functional diagram.
A momentary low signal applied to TRG causes the output to
go high. The external capacitor charges slowly through the
external resistor. When V
THR
(threshold voltage) reaches
2
3
V
S
, the output is switched off, discharging the capacitor.
During power-on, a single pulse may be generated.
Basic Astable Operation
Refer to the MIC1557 functional diagram.
The MIC1557 starts with T/T low, causing the output to go
high. The external capacitor charges slowly through the
external resistor. When V
T/T
reaches
2
3
V
S
(threshold volt-
age), the output is switched off, slowly discharging the
capacitor. When V
T/T
decreases to
1
3
V
S
(trigger voltage), the
output is switched on, causing V
T/T
to rise again, repeating
the cycle.
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| MIC1557BM5 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| MIC1557BM5 TR | 功能描述:IC OSC MONO TIMING 5MHZ SOT23-5 RoHS:否 類別:集成電路 (IC) >> 時鐘/計時 - 可編程計時器和振蕩器 系列:IttyBitty® 產(chǎn)品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:45 系列:- 類型:溫度 - 補償晶體振蕩器（TCXO） 計數(shù):- 頻率:25MHz 電源電壓:3.135 V ~ 3.465 V 電流 - 電源:1.5mA 工作溫度:-40°C ~ 85°C 封裝/外殼:16-SOIC（0.295"，7.50mm 寬） 包裝:管件 供應商設備封裝:16-SOIC W 安裝類型:表面貼裝 |
| MIC1557BM5TR | 制造商:Rochester Electronics LLC 功能描述: 制造商:RF Micro Devices Inc 功能描述: 制造商:Micrel Inc 功能描述: |
| MIC1557YM5 | 制造商:Rochester Electronics LLC 功能描述: 制造商:RF Micro Devices Inc 功能描述: |
| MIC1557YM5 TR | 功能描述:計時器和支持產(chǎn)品 2.7V to 18V, "555" RC Timer/Oscillator with Shutdown in SOT23-5 RoHS:否 制造商:Micrel 類型:Standard 封裝 / 箱體:SOT-23 內(nèi)部定時器數(shù)量:1 電源電壓-最大:18 V 電源電壓-最小:2.7 V 最大功率耗散: 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝:Reel |
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