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參數資料
| 型號： | MIC2595-1BM |
| 廠商： | MICREL INC |
| 元件分類： | 電源管理 |
| 英文描述： | Replaced by PTH05060W : |
| 中文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO14 |
| 封裝： | SOIC-14 |
| 文件頁數： | 15/17頁 |
| 文件大小： | 100K |
| 代理商： | MIC2595-1BM |
March 2004
15
M9999-031504
MIC2589/2595
Micrel
Applications Information
4-Wire Kelvin Sensing
Because of the low value typically required for the sense
resistor, special care must be used to measure accurately the
voltage drop across it. Specifically, the measurement tech-
nique across R
SENSE
must employ 4-wire Kelvin sensing.
This is simply a means of ensuring that any voltage drops in
the power traces connected to the resistors are not picked up
by the signal conductors measuring the voltages across the
sense resistors.
Figure 7 illustrates how to implement 4-wire Kelvin sensing.
As the figure shows, all the high current in the circuit (from V
EE
through R
SENSE
and then to the source of the output MOSFET)
flows directly through the power PCB traces and through
R
SENSE
. The voltage drop across R
SENSE
is sampled in such
a way that the high currents through the power traces will not
introduce any parasitic voltage drops in the sense leads. It is
recommended to connect the hot swap controller
’
s sense
leads directly to the sense resistor
’
s metalized contact pads.
R
SENSE
Power Trace
From V
EE
PCB Track Width:
0.03" per Ampere
using 1oz. Cu
Power Trace
To MOSFET Source
Signal Trace
to MIC2589/95 V
EE
Pin
Signal Trace
to MIC2589/95 SENSE Pin
Note: Each SENSE lead trace shall be
balanced for best performance
—
equal
length/equal aspect ratio.
R
SENSE
metalized
Figure 7. 4-Wire Kelvin Sense Connections for R
SENSE
Protection Against Voltage Transients
In many telecom applications, it is very common for circuit
boards to encounter large-scale supply-voltage transients in
backplane environments. Because backplanes present a
complex impedance environment, these transients can be as
high as 2.5 times steady-state levels, or 120V in worst-case
situations. In addition, a sudden load dump anywhere on the
circuit card can generate a very high voltage spike at the drain
of the output MOSFET which, in turn, will appear at the
DRAIN pin of the MIC2589/95. In both cases, it is good
engineering practice to include protective measures to avoid
damaging sensitive ICs or the hot swap controller from these
large-scale transients. Two typical scenarios in which large-
scale transients occur are described below:
1. An output current load dump with no bypass (charge
bucket or bulk) capacitance to V
EE
. For example,
if L
LOAD
= 5
μ
H, V
IN
= 56V and t
OFF
= 0.7
μ
s, the
resulting peak short-circuit current prior to the
MOSFET turning off would reach:
×
(
If there is no other path for this current to take when
the MOSFET turns off, it will avalanche the drain-
source junction of the MOSFET. Since the total
energy represented is small relative to the sturdi-
ness of modern power MOSFETs, it
’
s unlikely that
55V
0.7 s
5 H
= 7.7A
)
this will damage the transistor. However, the actual
avalanche voltage is unknown; all that can be
guaranteed is that it will be greater than the V
BD(D-
S)
of the MOSFET. The drain of the transistor is
connected to the DRAIN pin of the MIC2589/95,
and the resulting transient does have enough
voltage and energy and can damage this, or any,
high-voltage hot swap controller.
2. If the load
’
s bypass capacitance (for example, the
input filter capacitors for a set of DC-DC converter
modules) are on a board from which the board with
the MIC2589/95 and the MOSFET can be un-
plugged, the same type of inductive transient dam-
age can occur to the MIC2589/95.
Protecting the controller and the power MOSFET from dam-
age against these large-scale transients can take the forms
shown in Figure 8. It is not mandatory that these techniques
are used - the application environment will dictate suitability.
As protection against sudden on-card load dumps at the
DRAIN pin of the controller, a 2.2
μ
F or larger capacitor
directly from DRAIN to VEE of the controller can be used to
serve as a charge reservoir. Alternatively, a 68V, 1W, 5%
Zener diode clamp can be installed in a similar fashion. Note
that the clamp diode
’
s cathode is connected to the DRAIN pin
as shown in Figure 8. To protect the hot swap controller from
large-scale transients at the card input, a 100V clamp diode
(an SMAT70A or equivalent) can be used. In either case, the
lead lengths should be short and the layout compact to
prevent unwanted transients in the protection circuit.
[Circuit drawing under construction]
Figure 8. Using Large-Scale Transient Protection
Devices Around the MIC2589/95 and the
MIC2589R/95R
The same logic applies to the input of the MIC2589/95 circuit.
Power bus inductance could easily result in localized high-
voltage transients during a turn-off event. The potential for
overstressing the part in such a case should be kept in check
with a suitable input capacitor and/or transient clamping
diode.
Power MOSFET Selection
[Section under construction]
Power MOSFET Operating Voltage Requirements
[Section under construction]
Power MOSFET Steady-State Thermal Issues
[Section under construction]
Power MOSFET Transient Thermal Issues
[Section under construction]
PCB Layout Considerations
[Section under construction]
相關PDF資料 |
PDF描述 |
|---|---|
| MIC2595-2BM | Replaced by PTH05060W : |
| MIC2589R-1BM | SINGLE-CHANNEL NEGATIVE HIGH VOLTAGE HOT SWAP POWER CONTROLLERS/SEQUENCERS |
| MIC2753-RBM5 | Power Supply Supervisors Preliminary Information |
| MIC2753-SBM5 | Power Supply Supervisors Preliminary Information |
| MIC2754-LBM5 | Power Supply Supervisors Preliminary Information |
相關代理商/技術參數 |
參數描述 |
|---|---|
| MIC2595-1BM TR | 功能描述:IC CTRLR HOT SWAP NEG HV 14-SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產品培訓模塊:Obsolescence Mitigation Program 標準包裝:100 系列:- 類型:熱插拔開關 應用:通用 內部開關:是 電流限制:可調 電源電壓:9 V ~ 13.2 V 工作溫度:-40°C ~ 150°C 安裝類型:表面貼裝 封裝/外殼:10-WFDFN 裸露焊盤 供應商設備封裝:10-TDFN-EP（3x3） 包裝:管件 |
| MIC2595-1YM | 功能描述:熱插拔功率分布 Negative Voltage Hot-Swap Controller - Lead Free RoHS:否 制造商:Texas Instruments 產品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube |
| MIC2595-1YM TR | 功能描述:熱插拔功率分布 Negative Voltage Hot-Swap Controller - Lead Free RoHS:否 制造商:Texas Instruments 產品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube |
| MIC2595-1YM-TR | 功能描述:Hot Swap Controller, Sequencer 1 Channel -48V 14-SOIC 制造商:microchip technology 系列:- 包裝:剪切帶（CT） 零件狀態(tài):停產 類型:熱交換控制器，序列發(fā)生器 通道數:1 內部開關:無 應用:-48V 特性:閉鎖故障 可編程特性:限流，故障超時，UVLO 電壓 - 電源:-80 V ~ -19 V 電流 - 輸出（最大值）:- 工作溫度:-40°C ~ 85°C 電流 - 電源:4mA 安裝類型:表面貼裝 封裝/外殼:14-SOIC（0.154"，3.90mm 寬） 供應商器件封裝:14-SOIC 功能引腳:CFILTER，CNLD，DRAIN，PGTIMER，OFF，ON，PWRGD1，PWRGD2，PWRGD3 標準包裝:1 |
| MIC2595-2BM | 功能描述:IC CTRLR HOT SWAP NEG HV 14-SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產品培訓模塊:Obsolescence Mitigation Program 標準包裝:100 系列:- 類型:熱插拔開關 應用:通用 內部開關:是 電流限制:可調 電源電壓:9 V ~ 13.2 V 工作溫度:-40°C ~ 150°C 安裝類型:表面貼裝 封裝/外殼:10-WFDFN 裸露焊盤 供應商設備封裝:10-TDFN-EP（3x3） 包裝:管件 |
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