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參數(shù)資料
| 型號： | LTC1756EGN |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 其它接口 |
| 英文描述： | Smart Card Interface |
| 中文描述： | SPECIALTY INTERFACE CIRCUIT, PDSO16 |
| 封裝： | 0.150 INCH, PLASTIC, SSOP-16 |
| 文件頁數(shù)： | 7/12頁 |
| 文件大?。?/td> | 149K |
| 代理商： | LTC1756EGN |
7
LTC1756
APPLICATIO
S I
N
FOR
ATIO
U
10kV ESD Protection
All Smart Card pins (CLK, RST, I/O, V
CC
and GND) can
withstand over 10kV of human body model ESD in situ. In
order to ensure proper ESD protection, careful board
layout is required. The GND pin should be tied directly to
a ground plane. The V
CC
capacitor should be located very
close to the V
CC
pin and tied immediately to the ground
plane.
W
U
Capacitor Selection
The style and value of capacitors used with the LTC1756
determine several parameters such as output ripple volt-
age, charge pump strength, Smart Card switch debounce
time and V
CC
discharge rate.
Due to the switching nature of a capacitive charge pump,
low equivalent series resistance (ESR) capacitors are
recommended for the capacitors at V
IN
and V
CC
. When-
ever the flying capacitor is switched to the V
CC
charge
storage capacitor, considerable current flows. The prod-
uct of this high current and the ESR of the output capacitor
can generate substantial voltage spikes on the V
CC
output.
These spikes may cause problems with the Smart Card or
may interfere with the regulation loop of the LTC1756.
Therefore, ceramic or tantalum capacitors are recom-
mended rather than higher ESR aluminum capacitors.
Between ceramic and tantalum, ceramic capacitors gener-
ally have the lowest ESR. Some manufacturers have
developed low ESR tantalum capacitors but they can be
expensive and may still have higher ESR than ceramic
types. Thus, while they cannot be avoided, ESR spikes will
typically be lowest when using ceramic capacitors.
For ceramic capacitors there are several different materi-
als available to choose from. The choice of ceramic
material is generally based on factors such as available
capacitance, case size, voltage rating, electrical perfor-
mance and cost. For example, capacitors made of Y5V
material have high packing density, which provides high
capacitance for a given case size. However, Y5V capaci-
tors tend to lose considerable capacitance over the –40
°
C
to 85
°
C temperature range. X7R ceramic capacitors are
more stable over temperature but don’t provide the high
packing density. Therefore, large capacitance values are
generally not available in X7R ceramic.
The value and style of the flying capacitor are important
not only for the charge pump but also because they
provide the large debounce time for the Smart Card
detection channel. A 0.68
μ
F X7R capacitor is a good
choice for the flying capacitor because it provides fairly
constant capacitance over temperature and its value is not
prohibitively large.
The charge storage capacitor on the V
CC
pin determines
the ripple voltage magnitude and the discharge time of the
Smart Card voltage. To minimize ripple, generally, a large
value is needed. However, to meet the V
CC
discharge rate
specification, the value should not exceed 20
μ
F. A 10
μ
F
capacitor can be used but the ripple magnitude will be
higher leading to worse apparent DC load regulation.
Typically a 15
μ
F to 18
μ
F Y5V ceramic capacitor is the best
choice for the V
CC
charge storage capacitor. For best
performance, this capacitor should be connected as close
as possible to the V
CC
and GND pins. Note that most of the
electrostatic discharge (ESD) current on the Smart Card
pins is absorbed by this capacitor.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
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| LTC1756EGN#PBF | 功能描述:IC SMART CARD INTERFACE 16SSOP RoHS:是 類別:集成電路 (IC) >> 接口 - 專用 系列:- 特色產(chǎn)品:NXP - I2C Interface 標(biāo)準(zhǔn)包裝:1 系列:- 應(yīng)用:2 通道 I²C 多路復(fù)用器 接口:I²C，SM 總線 電源電壓:2.3 V ~ 5.5 V 封裝/外殼:16-TSSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:16-TSSOP 包裝:剪切帶 (CT) 安裝類型:表面貼裝 產(chǎn)品目錄頁面:825 (CN2011-ZH PDF) 其它名稱:568-1854-1 |
| LTC1756EGN#TR | 功能描述:IC SMART CARD INTERFACE 16SSOP RoHS:否 類別:集成電路 (IC) >> 接口 - 專用 系列:- 特色產(chǎn)品:NXP - I2C Interface 標(biāo)準(zhǔn)包裝:1 系列:- 應(yīng)用:2 通道 I²C 多路復(fù)用器 接口:I²C，SM 總線 電源電壓:2.3 V ~ 5.5 V 封裝/外殼:16-TSSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:16-TSSOP 包裝:剪切帶 (CT) 安裝類型:表面貼裝 產(chǎn)品目錄頁面:825 (CN2011-ZH PDF) 其它名稱:568-1854-1 |
| LTC1756EGN#TRPBF | 功能描述:IC SMART CARD INTERFACE 16SSOP RoHS:是 類別:集成電路 (IC) >> 接口 - 專用 系列:- 特色產(chǎn)品:NXP - I2C Interface 標(biāo)準(zhǔn)包裝:1 系列:- 應(yīng)用:2 通道 I²C 多路復(fù)用器 接口:I²C，SM 總線 電源電壓:2.3 V ~ 5.5 V 封裝/外殼:16-TSSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:16-TSSOP 包裝:剪切帶 (CT) 安裝類型:表面貼裝 產(chǎn)品目錄頁面:825 (CN2011-ZH PDF) 其它名稱:568-1854-1 |
| LTC1757A-1EMS8 | 功能描述:IC CTRLR RF POWER SINGLE 8MSOP RoHS:否 類別:RF/IF 和 RFID >> RF 電源控制器 IC 系列:- 標(biāo)準(zhǔn)包裝:3,000 系列:- RF 型:GSM 頻率:450MHz ~ 2GHz 特點(diǎn):四頻帶 封裝/外殼:8-VFBGA 供應(yīng)商設(shè)備封裝:8-MicroSMD（1.51x1.51） 包裝:帶卷 (TR) 其它名稱:LMV243BLX |
| LTC1757A-1EMS8#PBF | 功能描述:IC CTRLR RF POWER SINGLE 8MSOP RoHS:是 類別:RF/IF 和 RFID >> RF 電源控制器 IC 系列:- 標(biāo)準(zhǔn)包裝:3,000 系列:- RF 型:GSM 頻率:450MHz ~ 2GHz 特點(diǎn):四頻帶 封裝/外殼:8-VFBGA 供應(yīng)商設(shè)備封裝:8-MicroSMD（1.51x1.51） 包裝:帶卷 (TR) 其它名稱:LMV243BLX |
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