- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄26833 > MM54HC4538J (NATIONAL SEMICONDUCTOR CORP) HC/UH SERIES, DUAL MONOSTABLE MULTIVIBRATOR, CDIP16 PDF資料下載
參數(shù)資料
| 型號： | MM54HC4538J |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 諧振器 |
| 英文描述： | HC/UH SERIES, DUAL MONOSTABLE MULTIVIBRATOR, CDIP16 |
| 封裝： | CERAMIC, DIP-16 |
| 文件頁數(shù)： | 8/10頁 |
| 文件大?。?/td> | 199K |
| 代理商： | MM54HC4538J |
Timing Diagram
Circuit Operation
The ’HC4538 operates as follows (refer to logic diagram). In
the quiescent state, the external timing capacitor, C
X,is
charged to V
CC. When a trigger occurs, the Q output goes
high and C
X discharges quickly to the lower reference volt-
age (V
REF Lower =
1
3 V
CC). CX then charges, through RX,
back up to the upper reference voltage (V
REF Upper =
2
3
V
CC), at which point the one-shot has timed out and the Q
output goes low.
The following, more detailed description of the circuit opera-
tion refers to both the logic diagram and the timing diagram.
QUIESCENT STATE
In the quiescent state, before an input trigger appears, the
output latch is high and the reset latch is high (#1 in logic dia-
gram).
Thus the Q output (pin 6 or 10) of the monostable multivibra-
tor is low (#2, timing diagram).
The output of the trigger-control circuit is low (#3), and tran-
sistors M1, M2, and M3 are turned off. The external timing
capacitor, C
X, is charged to VCC (#4), and the upper refer-
ence circuit has a low output (#5). Transistor M4 is turned on
and transmission gate T1 is turned off. Thus the lower refer-
ence circuit has V
CC at the noninverting input and a resulting
low output (#6).
In addition, the output of the trigger-control reset circuit is
low.
TRIGGER OPERATION
The ’HC4538 is triggered by either a rising-edge signal at in-
putA(#7) or a falling-edge signal at input B (#8), with the un-
used trigger input and the Reset input held at the voltage lev-
els shown in the Truth Table. Either trigger signal will cause
the output of the trigger-control circuit to go high (#9).
The trigger-control circuit going high simultaneously initiates
three events. First, the output latch goes low, thus taking the
Q output of the ’HC4538 to a high state (#10). Second, tran-
sistor M3 is turned on, which allows the external timing ca-
pacitor, C
X, to rapidly discharge toward ground (#11). (Note
that the voltage across C
X appears at the input of the upper
reference circuit comparator.) Third, transistor M4 is turned
off and transmission gate T1 is turned on, thus allowing the
voltage across C
X to also appear at the input of the lower ref-
erence circuit comparator.
When C
X discharges to the reference voltage of the lower
reference circuit (#12), the outputs of both reference circuits
will be high (#13). The trigger-control reset circuit goes high,
resetting the trigger-control circuit flip-flop to a low state
(#14). This turns transistor M3 off again, allowing C
X to begin
to charge back up toward V
CC, with a time constant t = RXCX
(#15). In addition, transistor M4 is turned on and transmis-
sion gate T1 is turned off. Thus a high voltage level is applied
to the input of the lower reference circuit comparator, caus-
ing its output to go low (#16). The monostable multivibrator
may be retriggered at any time after the trigger-control circuit
goes low.
When C
X charges up to the reference voltage of the upper
reference circuit (#17), the output of the upper reference cir-
cuit goes low (#18). This causes the output latch to toggle,
taking the Q output of the ’HC4538 to a low state (#19), and
completing the time-out cycle.
DS005217-4
7
www.fairchildsemi.com
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MM54HC4543E | HC/UH SERIES, SEVEN SEGMENT DECODER/DRIVER, CONFIGURABLE OUTPUT, CQCC20 |
| MM54HC534J | HC/UH SERIES, 8-BIT DRIVER, INVERTED OUTPUT, CDIP20 |
| MM54HC573E | HC/UH SERIES, 8-BIT DRIVER, TRUE OUTPUT, CQCC20 |
| MM74HC573N | HC/UH SERIES, 8-BIT DRIVER, TRUE OUTPUT, PDIP20 |
| MM74HC573WMX | HC/UH SERIES, 8-BIT DRIVER, TRUE OUTPUT, PDSO20 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MM54HC4543 WAF | 制造商:Texas Instruments 功能描述: |
| MM54HC51 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Dual AND-OR-Invert Gate / Dual AND-OR Gate |
| MM54HC51J | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Dual AND-OR-Invert Gate / Dual AND-OR Gate |
| MM54HC533 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:TRI-STATE-R Octal D-Type Latch with Inverted Outputs |
| MM54HC533J | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:TRI-STATE-R Octal D-Type Latch with Inverted Outputs |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。