參數(shù)資料
型號: MAX4376-MAX4378
廠商: Maxim Integrated Products, Inc.
英文描述: Differential Bus Transceiver 8-SOIC -40 to 85
中文描述: 單/雙/四路高邊電流增益內(nèi)部檢測放大器
文件頁數(shù): 7/9頁
文件大?。?/td> 223K
代理商: MAX4376-MAX4378
M
Single/Dual/Quad High-Side Current-Sense
Amplifiers with Internal Gain
_______________________________________________________________________________________
7
Detailed Description
The MAX4376/MAX4377/MAX4378 high-side current-
sense amplifiers feature a 0 to +28V input common-mode
range that is independent of supply voltage. This feature
allows the monitoring of current out of a battery in deep
discharge and also enables high-side current sensing at
voltages greater than the supply voltage (V
CC
).
The MAX4376/MAX4377/MAX4378 operate as follows:
current from the source flows through R
SENSE
to the
load (Figure 1). Since the internal sense amplifier
s
inverting input has high impedance, negligible current
flows through RG2 (neglecting the input bias current).
Therefore, the sense amplifier
s inverting-input voltage
equals V
SOURCE
- (I
LOAD
)(R
SENSE
).
The amplifier
s open-loop gain forces its noninverting
input to the same voltage as the inverting input.
Therefore, the drop across RG1 equals (I
LOAD
)
(R
SENSE
). Since I
RG1
flows through RG1, I
RG1
=
(I
LOAD
)(R
SENSE
)/RG1. The internal current mirror multi-
plies I
RG1
by a current gain factor,
β
, to give I
RGD
=
β
x
I
RG1
. Solving I
RGD
=
β
x (I
LOAD
)(R
SENSE
)/RG1.
Therefore:
V
OUT
=
β
x (RGD/RG1)(R
SENSE
x I
LOAD
) x amp gain
where amp gain is 2, 5, or 10.
The part
s gain equals (
β
x RGD / RG1) x amp gain.
Therefore:
V
OUT
= (GAIN)(R
SENSE
)(I
LOAD
)
where GAIN = 20 for MAX437_T.
GAIN = 50 for MAX437_F.
GAIN = 100 for MAX437_H.
Set the full-scale output range by selecting R
SENSE
and
the appropriate gain version of the MAX4376/
MAX4377/MAX4378.
Applications Information
Recommended Component Values
The MAX4376/MAX4377/MAX4378 sense a wide variety
of currents with different sense resistor values. Table 1
lists common resistor values for typical operation of the
MAX4376/MAX4377/MAX4378.
Choosing R
SENSE
To measure lower currents more accurately, use a high
value for R
SENSE
. The high value develops a higher
sense voltage that reduces offset voltage errors of the
internal op amp.
In applications monitoring very high currents, R
SENSE
must be able to dissipate the I
2
R losses. If the resistor
s
rated power dissipation is exceeded, its value may drift
or it may fail altogether, causing a differential voltage
across the terminals in excess of the absolute maxi-
mum ratings.
If I
SENSE
has a large high-frequency component, mini-
mize the inductance of R
SENSE
. Wire-wound resistors
have the highest inductance, metal-film resistors are
somewhat better, and low-inductance metal-film resis-
tors are best suited for these applications.
Bidirectional Current-Sense Amplifier
Systems such as laptop computers and other devices
that have internal charge circuitry require a precise
bidirectional current-sense amplifier to monitor accu-
rately the battery
s current regardless of polarity. Figure
2 shows the MAX4377 used as a bidirectional current
Pin Description
PIN
MAX4376
MAX4376
MAX4377
μMAX-8/
SO-8
MAX4378
SO-14/
TSSOP-14
SOT23-5
SO-8
NAME
FUNCTION
1
4
1, 7
1, 7, 8, 14
OUT, OUT_
Output Voltage. V
OUT_
is proportional to the magnitude
of the sense voltage (V
RS+
- V
RS-
). V
OUT_
is
approximately zero when V
RS
-
> V
RS
-
+
(no phase
reversal).
Ground
Supply Voltage
Power connection to the external sense resistor
Load-side connection to the external sense resistor
No Connection. Not internally connected.
2
3
4
5
3
1
8
6
4
8
11
4
GND
V
CC
3, 5
2, 6
3, 5, 10, 12
2, 6, 9, 13
RS+, RS_+
RS-, RS_-
N.C.
2, 5, 7
相關(guān)PDF資料
PDF描述
MAX4377 Differential Bus Transceiver 8-SOIC -40 to 85
MAX4378TASD Differential Bus Transceiver 8-PDIP -40 to 85
MAX4378 Quad High-Side Current-Sense Amplifiers with Internal Gain(帶內(nèi)部增益,四路高邊電流感應(yīng)放大器)
MAX4376HAUK-T Single/Dual/Quad High-Side Current-Sense Amplifiers with Internal Gain
MAX4377HASA Single/Dual/Quad High-Side Current-Sense Amplifiers with Internal Gain
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX4376TASA 功能描述:電流靈敏放大器 High-Side Current-Sense Amp RoHS:否 制造商:Texas Instruments 通道數(shù)量: 共模抑制比(最小值):110 dB 輸入補償電壓:80 uV 電源電壓-最大:5.5 V 電源電壓-最小:2.7 V 電源電流:350 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-16 封裝:Reel
MAX4376TASA+ 功能描述:電流靈敏放大器 High-Side Current-Sense Amp RoHS:否 制造商:Texas Instruments 通道數(shù)量: 共模抑制比(最小值):110 dB 輸入補償電壓:80 uV 電源電壓-最大:5.5 V 電源電壓-最小:2.7 V 電源電流:350 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-16 封裝:Reel
MAX4376TASA+T 功能描述:電流靈敏放大器 High-Side Current-Sense Amp RoHS:否 制造商:Texas Instruments 通道數(shù)量: 共模抑制比(最小值):110 dB 輸入補償電壓:80 uV 電源電壓-最大:5.5 V 電源電壓-最小:2.7 V 電源電流:350 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-16 封裝:Reel
MAX4376TASA-T 功能描述:電流靈敏放大器 High-Side Current-Sense Amp RoHS:否 制造商:Texas Instruments 通道數(shù)量: 共模抑制比(最小值):110 dB 輸入補償電壓:80 uV 電源電壓-最大:5.5 V 電源電壓-最小:2.7 V 電源電流:350 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-16 封裝:Reel
MAX4376TAUK 制造商:Maxim Integrated Products 功能描述:5 PINS SOT PKG - Cut Tape Product