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參數(shù)資料
| 型號： | MIC2536-1BM |
| 廠商： | MICREL INC |
| 元件分類： | 電源管理 |
| 英文描述： | Dual USB Power Distribution Switch Preliminary Information |
| 中文描述： | 2-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8 |
| 封裝： | SOP-8 |
| 文件頁數(shù)： | 10/12頁 |
| 文件大?。?/td> | 132K |
| 代理商： | MIC2536-1BM |
MIC2536
10
March 2000
MIC2536
Micrel
ENA
FLGA
FLGB
ENB
OUTA
IN
GND
OUTB
MIC2536-2
3.3V USB Controller
0.1μF
V
BUS
D+
D
–
GND
Data
(Two Pair)
to USB
Controller
V
BUS
D+
D
–
GND
USB
Port 2
USB
Port 1
MIC5207-3.3
63μF
63μF
Ferrite
Beads
4.50V to 5.25V
Upstream V
BUS
100mA max.
V
BUS
D+
D
–
GND
Data
4.7μF
1μF
1.5k
ON/OFF
OVERCURRENT
OVERCURRENT
ON/OFF
VIN
10k
IN
OUT
GND
.01μF
.01μF
10k
Figure 4. USB Two-Port Bus-Powered Hub
Universal Serial Bus (USB) Power Distribution
Applications
The MIC2536 is ideally suited for USB (Universal Serial Bus)
power distribution applications. For Bus-Powered hubs, USB
requires that each downstream port be switched on or off
under control by the host. Up to four downstream ports each
capable of supplying 100mA at 4.4V minimum are allowed. In
additon, to reduce voltage droop on the upstream bus the hub
must consume only 100mA max at start-up until it enumer-
ates with the host prior to requesting more power. The same
requirements apply for bus-powered peripherals that have no
downstream ports. Figure 4 shows a two-port bus-powered
hub.
Bus-Powered Hub Port Switching
The USB Specification requires that bus-powered hubs imple-
ment port switching on either a ganged or individual basis.
The specific implementation must be reported via the Hub
Descriptor Status Register. Individual port switching has
advantages in that a fault on one port will not prevent the other
ports from operating correctly. In addition, a soft-start circuit
must be included in order to reduce inrush currents when the
switch is enabled. To meet this requirement, the MIC2536
has been designed to slowly ramp its output.
Suspend Current
Universal Serial Bus Specificationplaces a maximum sus-
pend current requirement of 500
μ
A on devices. For hubs,
Universal Serial Bus Specification Revision 1.1clarifies this
issue. Revision 1.1, section 7.2.3, stipulates that the maxi-
mum suspend current for a configured hub is 2.5mA. This
number is derived by allocating 500
μ
A for up to four down-
stream ports plus 500
μ
A for the hub
’
s internal functions. A
nonconfigured hub is considered a low-power device and
may not consume more than 500
μ
A. In a nonconfigured state
all downstream devices will be switched off. In most cases, a
nonconfigured hub is not a practical state for the system.
Therefore, the 2.5mA specification is the applicable target
specification for the suspend state. In a bus-powered hub
with less than 4 ports, the hub may use the additional current
for internal functions.
The 500
μ
A worst case suspend current must be further
divided among the data port termination resistors and internal
functions. The termination resistors will consume
3.6V
÷
(16.5K
–
5%) = 230
μ
A. This leaves only 270
μ
A for
internal functions. Assuming 100
μ
A as the maximum USB
controller suspend current, 170
μ
A remains for the rest of the
system. The MIC2536 will consume 100
μ
A maximum, leav-
ing a margin of 70
μ
A.
USB Voltage Regulation
USB specifications require a minimum downstream voltage
supply of 4.40V from a bus-powered hub port (See Applica-
tion Note 17for details). The USB specification allows for a
100mV drop across the hub, leaving 250mV for PCB, up-
stream cable, and connector resistance. Therefore, the on-
resistance of the switch for each port, not including PCB
resistance, must be <100mV
÷
100mA = 1
. The MIC2536
has a maximum on-resistance of 700m
, which easily satis-
fies this requirement.
Overcurrent Indication
The USB Specification does not require bus-powered hubs to
report overcurrent conditions to the host, since the hub is
already current-limited at the upstream port. However, if it is
desired to report overcurrent, the Hub Descriptor Status
Register must be programmed to indicate this. The MIC2536
provides a flag output for this application.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MIC2536-1BMM | Dual USB Power Distribution Switch Preliminary Information |
| MIC2536-2BM | Dual USB Power Distribution Switch Preliminary Information |
| MIC2536-2BMM | Dual USB Power Distribution Switch Preliminary Information |
| MIC2537 | Quad Power Distribution Switch(四獨立通道 電源分配開關(guān)) |
| MIC2537-1BM | Quad Power Distribution Switch Preliminary Information |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MIC2536-1BM TR | 功能描述:IC USB SWITCH DUAL 8-SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 電源分配開關(guān) 系列:- 特色產(chǎn)品:XRP252 Switches 標(biāo)準(zhǔn)包裝:1 系列:- 類型:高端開關(guān) 輸出數(shù):2 Rds（開）:140 毫歐 內(nèi)部開關(guān):是 電流限制:1.15A 輸入電壓:1.75 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:10-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:10-TDFN（3x3） 包裝:Digi-Reel® 其它名稱:1016-1691-6 |
| MIC2536-1BMM | 功能描述:IC USB SWITCH DUAL 8-MSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 電源分配開關(guān) 系列:- 特色產(chǎn)品:XRP252 Switches 標(biāo)準(zhǔn)包裝:1 系列:- 類型:高端開關(guān) 輸出數(shù):2 Rds（開）:140 毫歐 內(nèi)部開關(guān):是 電流限制:1.15A 輸入電壓:1.75 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:10-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:10-TDFN（3x3） 包裝:Digi-Reel® 其它名稱:1016-1691-6 |
| MIC2536-1BMM TR | 功能描述:IC USB SWITCH DUAL 8-MSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 電源分配開關(guān) 系列:- 特色產(chǎn)品:XRP252 Switches 標(biāo)準(zhǔn)包裝:1 系列:- 類型:高端開關(guān) 輸出數(shù):2 Rds（開）:140 毫歐 內(nèi)部開關(guān):是 電流限制:1.15A 輸入電壓:1.75 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:10-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:10-TDFN（3x3） 包裝:Digi-Reel® 其它名稱:1016-1691-6 |
| MIC2536-1YM | 功能描述:電源開關(guān) IC - USB Dual USB Switch - Lead Free RoHS:否 制造商:Micrel 電源電壓-最小:2.7 V 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:SOIC-8 封裝:Tube |
| MIC2536-1YM TR | 功能描述:電源開關(guān) IC - USB Dual USB Switch - Lead Free RoHS:否 制造商:Micrel 電源電壓-最小:2.7 V 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:SOIC-8 封裝:Tube |
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