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參數(shù)資料
| 型號： | ISL84684 |
| 廠商： | Intersil Corporation |
| 元件分類： | DRAM |
| 英文描述： | 1024 x 36 synchronous FIFO Memory 132-BQFP 0 to 70 |
| 中文描述： | 超低導通電阻，低電壓，單電源，雙路SPDT模擬開關 |
| 文件頁數(shù)： | 7/11頁 |
| 文件大?。?/td> | 406K |
| 代理商： | ISL84684 |
7
This method is not acceptable for the signal path inputs.
Adding a series resistor to the switch input defeats the
purpose of using a low R
ON
switch, so two small signal
diodes can be added in series with the supply pins to provide
overvoltage protection for all pins (see Figure 8). These
additional diodes limit the analog signal from 1V below V+ to
1V above GND. The low leakage current performance is
unaffected by this approach, but the switch signal range is
reduced and the resistance may increase, especially at low
supply voltages.
Power-Supply Considerations
The ISL84684 construction is typical of most single supply
CMOS analog switches, in that they have two supply pins:
V+ and GND. V+ and GND drive the internal CMOS
switches and set their analog voltage limits. Unlike switches
with a 4V maximum supply voltage, the ISL84684 4.8V
maximum supply voltage provides plenty of room for the
10% tolerance of 3.6V supplies, as well as room for
overshoot and noise spikes.
The minimum recommended supply voltage is 1.65V but the
part will operate with a supply below 1.5V. It is important to
note that the input signal range, switching times, and on-
resistance degrade at lower supply voltages. Refer to the
electrical specification tables and
Typical Performance
curves for details.
V+ and GND also power the internal logic and level shiftiers.
The level shiftiers convert the input logic levels to switched
V+ and GND signals to drive the analog switch gate
terminals.
This family of switches cannot be operated with bipolar
supplies, because the input switching point becomes
negative in this configuration.
Logic-Level Thresholds
This switch family is 1.8V CMOS compatible (0.5V and 1.4V)
over a supply range of 2.0V to 3.6V (see Figure 15). At 3.6V
the V
IH
level is about 1.27V. This is still below the 1.8V
CMOS guaranteed high output minimum level of 1.4V, but
noise margin is reduced.
The digital input stages draw supply current whenever the
digital input voltage is not at one of the supply rails. Driving
the digital input signals from GND to V+ with a fast transition
time minimizes power dissipation.
High-Frequency Performance
In 50
systems, the signal response is reasonably flat even
past 30MHz with a -3dB bandwidth of 120MHz (see Figure
16). The frequency response is very consistent over a wide
V+ range, and for varying analog signal levels.
An OFF switch acts like a capacitor and passes higher
frequencies with less attenuation, resulting in signal
feedthrough from a switch’s input to its output. Off Isolation is
the resistance to this feedthrough, while Crosstalk indicates
the amount of feedthrough from one switch to another.
Figure 17 details the high Off Isolation and Crosstalk
rejection provided by this part. At 100kHz, Off Isolation is
about 68dB in 50
systems, decreasing approximately 20dB
per decade as frequency increases. Higher load
impedances decrease Off Isolation and Crosstalk rejection
due to the voltage divider action of the switch OFF
impedance and the load impedance.
Leakage Considerations
Reverse ESD protection diodes are internally connected
between each analog-signal pin and both V+ and GND. One of
these diodes conducts if any analog signal exceeds V+ or
GND.
Virtually all the analog leakage current comes from the ESD
diodes to V+ or GND. Although the ESD diodes on a given
signal pin are identical and therefore fairly well balanced,
they are reverse biased differently. Each is biased by either
V+ or GND and the analog signal. This means their leakages
will vary as the signal varies. The difference in the two diode
leakages to the V+ and GND pins constitutes the analog-
signal-path leakage current. All analog leakage current flows
between each pin and one of the supply terminals, not to the
other switch terminal. This is why both sides of a given
switch can show leakage currents of the same or opposite
polarity. There is no connection between the analog signal
paths and V+ or GND.
FIGURE 8. OVERVOLTAGE PROTECTION
GND
V
COM
V
NO or NC
OPTIONAL PROTECTION
DIODE
V+
IN
X
OPTIONAL PROTECTION
DIODE
OPTIONAL
PROTECTION
RESISTOR
ISL84684
相關PDF資料 |
PDF描述 |
|---|---|
| ISL84684IR-T | Ultra Low ON-Resistance, Low Voltage, Single Supply, Dual SPDT Analog Switch |
| ISL84684IUZ | Ultra Low ON-Resistance, Low Voltage, Single Supply, Dual SPDT Analog Switch |
| ISL84684IUZ-T | Ultra Low ON-Resistance, Low Voltage, Single Supply, Dual SPDT Analog Switch |
| ISL84684IRZ-T | Ultra Low ON-Resistance, Low Voltage, Single Supply, Dual SPDT Analog Switch |
| ISL84684IR | Ultra Low ON-Resistance, Low Voltage, Single Supply, Dual SPDT Analog Switch |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| ISL84684_07 | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Ultra Low ON-Resistance, Low Voltage, Single Supply, Dual SPDT Analog Switch |
| ISL84684II | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Ultra Low ON-Resistance, Low Voltage, Single Supply, Dual SPDT Analog Switch in Chipscale Package |
| ISL84684IIEVAL1 | 功能描述:EVAL BOARD 1 FOR ISL84684II RoHS:否 類別:編程器，開發(fā)系統(tǒng) >> 評估演示板和套件 系列:* 標準包裝:1 系列:PSoC® 主要目的:電源管理，熱管理 嵌入式:- 已用 IC / 零件:- 主要屬性:- 次要屬性:- 已供物品:板，CD，電源 |
| ISL84684IIZ-T | 功能描述:IC SWITCH DUAL SPDT 10WLCSP RoHS:是 類別:集成電路 (IC) >> 接口 - 模擬開關，多路復用器，多路分解器 系列:- 標準包裝:48 系列:- 功能:開關 電路:4 x SPST - NO 導通狀態(tài)電阻:100 歐姆 電壓電源:單/雙電源 電壓 - 電源，單路/雙路(±):2 V ~ 12 V，±2 V ~ 6 V 電流 - 電源:50nA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:16-SOIC（0.154"，3.90mm 寬） 供應商設備封裝:16-SOIC 包裝:管件 |
| ISL84684IIZ-TS | 制造商:Rochester Electronics LLC 功能描述: 制造商:Intersil Corporation 功能描述: |
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