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參數(shù)資料
| 型號： | MC34058 |
| 廠商： | Motorola, Inc. |
| 英文描述： | 5-V Battery-Backup Supervisors for RAM Retention 8-MSOP -40 to 85 |
| 中文描述： | 六角環(huán)評- 485收發(fā)器與三態(tài)輸出 |
| 文件頁數(shù)： | 8/12頁 |
| 文件大小： | 237K |
| 代理商： | MC34058 |
MC34058 MC34059
Figure 10. Typical EIA/TIA–485 Application
8
MOTOROLA ANALOG IC DEVICE DATA
RT
120
RT
120
EIA/TIA–422 specifications require the ability to drive at
least 10 receivers of input impedance of greater than or equal
to 4.0 K
plus the 100
termination resistor. This protocol
was intended for unidirectional transmission. EIA/TIA–485 is
capable of bidirectional transmission by allowing multiple
drivers and receivers on the same twisted pair segment. The
loading of the twisted pair segment can be up to 32 Unit
Loads (U.L.) plus the two 120
terminating resistors. The
U.L. definition is shown in Figure 11.
Figure 11. TIA/EIA–485 Unit Load Definition
–0.8 mA
Ii
Vi
+12 V
+5.0 V
–7.0 V
–3.0 V
Calculating Power Dissipation for the
MC34058/9 Hex–Transceiver.
The operational temperature range is listed as 0
°
C to 70
°
C
to satisfy both EIA/TIA–485 and EIA/TIA–422 specifications.
However, a lower ambient temperature may be required
depending on the specific board layout and/or application.
Using a first order approximation for heat transfer, the
maximum power which may be dissipated by the package is
determined by (see Appendix A for more details);
TJmax– TA
PDmax
θ
ja
[1]
where:
θ
ja = package thermal resistance (see Appendix A)
TJmax = Maximum Junction Temperature. Since the
thermal shutdown feature has a trip point of 150
°
C
±
20
°
,
TJmax is selected to be +130
°
C.
TA = Ambient Operating Temperature.
The power generated within the package is then;
PD
VCC– VOH1
· IOH1
VOL1
· IOL1
..
[2]
(each_driver)..
VCC– VOH6
· IOH6
VOL6
· IOL6
VCC· ICCQ
As indicated in the equation, the part of Equation 2
consisting of IOH , VOH , IOL and VOL must be calculated for
each of the drivers and summed for the total power
dissipation estimate. The last term can be considered the
quiescent power required to keep the IC operational and is
measured with the drivers idle and unloaded. The VOH and
VOL terms can be determined from the output current
versus output voltage curves which provide driver output
characteristics.
Example 1 estimates thermal performance based on
current requirements.
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| MC34058FTA | 5-V Battery-Backup Supervisors for RAM Retention 8-MSOP -40 to 85 |
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相關(guān)代理商/技術(shù)參數(shù) |
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|---|---|
| MC34058FTA | 制造商:MOTOROLA 制造商全稱:Motorola, Inc 功能描述:HEX EIA-485 TRANSCEIVER with THREE-STATE OUTPUTS |
| MC34059 | 制造商:MOTOROLA 制造商全稱:Motorola, Inc 功能描述:HEX EIA-485 TRANSCEIVER with THREE-STATE OUTPUTS |
| MC34059FTA | 制造商:MOTOROLA 制造商全稱:Motorola, Inc 功能描述:HEX EIA-485 TRANSCEIVER with THREE-STATE OUTPUTS |
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| MC3406 | 制造商:SHENZHENFREESCALE 制造商全稱:ShenZhen FreesCale Electronics. Co., Ltd 功能描述:N-Channel 30-V (D-S) MOSFET High performance trench technology |
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