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參數資料
| 型號： | TPS2202Y |
| 廠商： | Texas Instruments, Inc. |
| 英文描述： | DUAL-SLOT PC CARD POWER-INTERFACE SWITCHES FOR SERIAL PCMCIA CONTROLLERS |
| 中文描述： | 雙插槽PC卡電源接口開關用于串行PCMCIA控制器 |
| 文件頁數： | 14/21頁 |
| 文件大?。?/td> | 455K |
| 代理商： | TPS2202Y |
TPS2202, TPS2202Y
DUAL-SLOT PC CARD POWER-INTERFACE SWITCHES
FOR SERIAL PCMCIA CONTROLLERS
SLVS103A – DECEMBER 1994 – REVISED AUGUST 1995
6–14
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
APPLICATION INFORMATION
overview
PC Cards were initially introduced as a means to add EEPROM (flash memory) to portable computers with
limited on-board memory. The idea of add-in cards quickly took hold: modems, wireless LANs, GPS systems,
multimedia, and hard-disk versions were soon available. As the number of PC Card applications grew, the
engineering community quickly recognized the need for a standard to ensure compatibility across platforms.
To this end, the PCMCIA (Personal Computer Memory Card International Association) was established and was
comprised of members from leading computer, software, PC card, and semiconductor manufacturers. One key
goal was to realize the concept of plug and play – cards and hosts from different vendors should be compatible
and able to communicate with one another transparently.
PC Card power specification
System compatibility also means power compatibility. The most current set of specifications (PC Card Standard)
set forth by the PCMCIA committee states that power is to be transferred between the host and the card through
eight of the PC Card connector’s 68 pins. This power interface consists of two V
CC
, two V
pp
, and four ground
pins. Multiple V
CC
and ground pins minimize connector-pin and line resistance. The two V
pp
pins were originally
specified as separate signals but are commonly tied together in the host to form a single node to minimize
voltage losses. Card primary power is supplied through the V
CC
pins; flash-memory programming and erase
voltage is supplied through the V
pp
pins. As each pin is rated to 0.5 A, V
CC
and V
pp
can theoretically supply up
to 1 A, assuming equal pin resistance and no pin failure. A conservative design would limit current to 500 mA.
Some applications, however, require higher V
CC
currents; disk drives, for example, may need as much as
750-mA peak current to create the initial torque necessary to spin up the platter. V
pp
currents, on the other hand,
are defined by flash-memory programming requirements, typically under 120 mA.
future power trends
The 1-A physical-pin current alluded to in the PC Card specification has caused some host-system engineers
to believe they are required to deliver 1 A within the voltage tolerance of the card. Future applications, such as
RF cards, could use the extra power for their radio transmitters. The 5 W needed for these cards will require
very robust power supplies and special cooling considerations. The limited number of host sockets that will be
able to support them makes the market for these high-powered PC Cards uncertain. The vast majority of the
cards require less than 600 mA continuous current and the trend is towards even lower-powered PC Cards that
will assure compatibility with a greater number of host systems. Recognizing the need for power derating, an
adhoc committee of the PCMCIA is currently working to limit the amount of steady-state dc current to the
PC Card to something less than the currently implied 1 A. If a system is designed to support 1 A, then the switch
r
DS(on)
, power supply requirements, and PC Card cooling need to be carefully considered.
designing around 1-A delivery
Delivering 1 A means minimizing voltage (and power) losses across the PC Card power interface, which
requires that designers trade off switch resistance and the cost associated with large-die (low r
DS(on)
) MOSFET
transistors. The PC Card standard requires that 5 V
±
5%, or 3.3 V
±
0.3 V be supplied to the card. The
approximate 10% tolerance for the 3.3-V supply makes the 3.3-V r
DS(on)
less critical than the 5-V switch. A
conservative approach is to allow 2% for voltage-regulator tolerance and 1% for etch- and terminal-resistance
drops, which leaves 2% (100 mV) voltage drop for the 5-V switch, and at least 6% (198 mV) for the 3.3-V switch.
Calculating the r
DS(on)
necessary to support a 100 mV or 198 mV switch loss, using R = E/I and setting I = 1 A,
the 5-V and 3.3-V switches would need to be 100 m
and 198 m
respectively. One solution would be to pay
for a more expensive switch with lower r
DS(on)
. A second, less expensive approach is to increase the headroom
of the power supply–for example, to increase the 5-V supply 1.5% or to 5.075
±
2%. Working through the
numbers once more, the 2% for the regulator plus 1 % for etch and terminal losses leaves 97% or 4.923 V.
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相關代理商/技術參數 |
參數描述 |
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| TPS2204APWP | 功能描述:熱插拔功率分布 1A Dual-Slot PC Card w/Serial Interface 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 |
| TPS2204APWPG4 | 功能描述:熱插拔功率分布 1A Dual-Slot PC Card Pwr Sw 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 |
| TPS2204APWPR | 功能描述:熱插拔功率分布 1A Dual-Slot PC Card w/Serial Interface 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 |
| TPS2204APWPRG4 | 功能描述:熱插拔功率分布 1A Dual-Slot PC Card w/Serial Interface 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 |
| TPS2205IDAP | 功能描述:熱插拔功率分布 1A Dual-Slot PC Card Power Switch 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 |
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