參數(shù)資料
型號: ISL28236
廠商: Intersil Corporation
英文描述: 5MHz, Single and Dual Precision Rail-to-Rail Input-Output (RRIO) Op Amps(5MHz,單/雙精密軌對軌輸入-輸出(RRIO)運放)
中文描述: 5MHz的,單和雙精密軌至軌輸入,輸出(RRIO)運算放大器(5MHz的,單/雙精密軌對軌輸入-輸出(RRIO)運放)
文件頁數(shù): 11/15頁
文件大小: 790K
代理商: ISL28236
11
FN6153.2
June 28, 2007
Applications Information
Introduction
The ISL28136 and ISL28236 are single and dual channel Bi-
CMOS rail-to-rail input, output (RRIO) micropower precision
operational amplifiers. The parts are designed to operate
from single supply (2.4V to 5.5V) or dual supply (±1.2V to
±2.75V). The parts have an input common mode range that
extends 0.25V above the positive rail and down to the
negative supply rail. The output operation can swing within
about 3mV of the supply rails with a 100k
Ω
load.
Rail-to-Rail Input
Many rail-to-rail input stages use two differential input pairs,
a long-tail PNP (or PFET) and an NPN (or NFET). Severe
penalties have to be paid for this circuit topology. As the
input signal moves from one supply rail to another, the
operational amplifier switches from one input pair to the
other causing drastic changes in input offset voltage and an
undesired change in magnitude and polarity of input offset
current.
The ISL28136 and ISL28236 achieve input rail-to-rail
operation without sacrificing important precision
specifications and degrading distortion performance. The
devices’ input offset voltage exhibits a smooth behavior
throughout the entire common-mode input range. The input
bias current versus the common-mode voltage range gives
an undistorted behavior from typically down to the negative
rail to 0.25V higher than the positive rail.
Rail-to-Rail Output
A pair of complementary Bi-polar devices are used to
achieve the rail-to-rail output swing. The PNP sinks current
to swing the output in the negative direction. The NPN
sources current to swing the output in the positive direction.
The ISL28136 and ISL28236 with a 100k
Ω
load will swing to
within 3mV of the positive supply rail and within 3mV of the
negative supply rail.
Results of Over-Driving the Output
Caution should be used when over-driving the output for long
periods of time. Over-driving the output can occur in two ways.
1) The input voltage times the gain of the amplifier exceeds the
supply voltage by a large value or, 2) The output current
required is higher than the output stage can deliver. These
conditions can result in a shift in the Input Offset Voltage (V
OS
)
as much as 1μV/hr. of exposure under these conditions.
IN+ and IN- Input Protection
All input terminals have internal ESD protection diodes to both
positive and negative supply rails, limiting the input voltage to
within one diode beyond the supply rails. They also contain
back-to-back diodes across the input terminals (“Pin
Descriptions” on page 10 - Circuit 1
)
. For applications where
the input differential voltage is expected to exceed 0.5V, an
external series resistor must be used to ensure the input
currents never exceed 5mA (Figure 38).
Enable/Disable Feature
The ISL28136 offers an EN pin that disables the device
when pulled up to at least 2.0V. In the disabled state (output
in a high impedance state), the part consumes typically 10μA
at room temperature. The EN pin has an internal pull down.
If left open, the EN pin will pull to the negative rail and the
device will be enabled by default. The EN pin should never
be left floating. When not used, the EN pin should either be
left floating or connected to the V- pin.
By disabling the part, multiple ISL28136 parts can be
connected together as a MUX. In this configuration, the
outputs are tied together in parallel and a channel can be
selected by the EN pin. The loading effects of the feedback
resistors of the disabled amplifier must be considered when
multiple amplifier outputs are connected together. Note that
feed through from the IN+ to IN- pins occurs on any Mux
Amp disabled channel where the input differential voltage
exceeds 0.5V (e.g., active channel V
OUT
= 1V, while
disabled channel V
IN
= GND), so the mux implementation is
best suited for small signal applications. If large signals are
required, use series IN+ resistors, or a large value R
F
, to
keep the feed through current low enough to minimize the
impact on the active channel. See the “Limitations of the
Differential Input Protection” section for more details.
Limitations of the Differential Input Protection
If the input differential voltage is expected to exceed 0.5V, an
external current limiting resistor must be used to ensure the
input current never exceeds 5mA. For non-inverting unity gain
applications, the current limiting can be via a series IN+ resistor,
or via a feedback resistor of appropriate value. For other gain
configurations, the series IN+ resistor is the best choice, unless
the feedback (R
F
) and gain setting (R
G
) resistors are both
sufficiently large to limit the input current to 5mA.
Large differential input voltages can arise from several
sources:
1) During open loop (comparator) operation. Used this way,
the IN+ and IN- voltages don’t track, so differentials arise.
2) When the amplifier is disabled but an input signal is still
present. An R
L
or R
G
to GND keeps the IN- at GND, while
the varying IN+ signal creates a differential voltage. Mux
Amp applications are similar, except that the active channel
V
OUT
determines the voltage on the IN- terminal.
FIGURE 38. INPUT CURRENT LIMITING
-
+
R
IN
R
L
V
IN
V
OUT
ISL28136, ISL28236
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ISL28236 WAF 制造商:Intersil Corporation 功能描述:
ISL28236FBZ 功能描述:IC OPAMP RRIO DUAL 5MHZ 8-SOIC RoHS:是 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 標準包裝:75 系列:MicroAmplifier™ 放大器類型:通用 電路數(shù):1 輸出類型:滿擺幅 轉(zhuǎn)換速率:0.03 V/µs 增益帶寬積:100kHz -3db帶寬:- 電流 - 輸入偏壓:1pA 電壓 - 輸入偏移:60µV 電流 - 電源:20µA 電流 - 輸出 / 通道:5mA 電壓 - 電源,單路/雙路(±):2.3 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC(0.154",3.90mm 寬) 供應(yīng)商設(shè)備封裝:8-SOIC 包裝:管件
ISL28236FBZ-T7 功能描述:IC OPAMP RRIO DUAL 5MHZ 8-SOIC RoHS:是 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 其它有關(guān)文件:TS1854A View All Specifications 標準包裝:50 系列:- 放大器類型:通用 電路數(shù):4 輸出類型:滿擺幅 轉(zhuǎn)換速率:0.25 V/µs 增益帶寬積:630kHz -3db帶寬:- 電流 - 輸入偏壓:16nA 電壓 - 輸入偏移:1000µV 電流 - 電源:162µA 電流 - 輸出 / 通道:48mA 電壓 - 電源,單路/雙路(±):1.8 V ~ 6 V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:14-SOIC(0.154",3.90mm 寬) 供應(yīng)商設(shè)備封裝:14-SO 包裝:管件
ISL28236FUZ 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:5MHz, Dual Precision Rail-to-Rail Input-Output (RRIO) Op Amp
ISL28236FUZ-T7 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:5MHz, Dual Precision Rail-to-Rail Input-Output (RRIO) Op Amp