OPA4379 [BB]

1.8V, 2.9uA, 90kHz, Rail-to-Rail I/O OPERATIONAL AMPLIFIERS; 1.8V , 2.9uA , 90KHz的轨至轨输入/输出运算放大器
OPA4379
型号: OPA4379
厂家: BURR-BROWN CORPORATION    BURR-BROWN CORPORATION
描述:

1.8V, 2.9uA, 90kHz, Rail-to-Rail I/O OPERATIONAL AMPLIFIERS
1.8V , 2.9uA , 90KHz的轨至轨输入/输出运算放大器

运算放大器
文件: 总12页 (文件大小:234K)
中文:  中文翻译
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OPA379  
OPA2379  
OPA4379  
SBOS347A − NOVEMBER 2005 − REVISED DECEMBER 2005  
1.8V, 2.9µA, 90kHz, Rail-to-Rail I/O  
OPERATIONAL AMPLIFIERS  
FD EATURES  
DESCRIPTION  
LOW NOISE: 2.8µV  
PP  
The OPA379 family of micropower, low-voltage  
D
D
D
microPower: 5.5µA (max)  
operational amplifiers is designed for battery-powered  
applications. These amplifiers operate on a supply voltage  
as low as 1.8V. High-performance, single-supply  
operation with rail-to-rail capability makes the OPA379  
family useful for a wide range of applications.  
LOW OFFSET VOLTAGE: 1.5mV (max)  
DC PRECISION:  
− CMRR: 100dB  
− PSRR: 2µV/V  
In addition to microSize packages, the OPA379 family of  
op amps features impressive bandwidth (90kHz), low bias  
current (25pA), and low noise (80nV/Hz) relative to the  
very low quiescent current (5.5µA max).  
− A : 120dB  
OL  
D
D
WIDE SUPPLY VOLTAGE RANGE: 1.8V to 5.5V  
microSize PACKAGES  
The OPA379 (single) is available in SC70-5, SOT23-5,  
and SO-8 packages. The OPA2379 (dual) comes in  
SOT23-8 and SO-8 packages. The OPA4379 (quad) is  
offered in a TSSOP-14 package. All versions are specified  
from −40°C to +125°C.  
AD PPLICATIONS  
BATTERY-POWERED INSTRUMENTS  
D
D
D
PORTABLE DEVICES  
MEDICAL INSTRUMENTS  
HANDHELD TEST EQUIPMENT  
OPAx379 RELATED PRODUCTS  
FEATURES  
PRODUCT  
OPAx349  
TLV240x  
TLV224x  
TLV27Lx  
TLV238x  
OPAx347  
TLV276x  
OPAx348  
1µA, 70kHz, 2mV V , 1.8V to 5.5V Supply  
OS  
1µA, 5.5kHz, 390µV V , 2.5V to 16V Supply  
OS  
1µA, 5.5kHz, 0.6mV V , 2.5V to 12V Supply  
OS  
7µA, 160kHz, 0.5mV V , 2.7V to 16V Supply  
OS  
7µA, 160kHz, 0.5mV V , 2.7V to 16V Supply  
OS  
20µA, 350kHz, 2mV V , 2.3V to 5.5V Supply  
OS  
20µA, 500kHz, 550µV V , 1.8V to 3.6V Supply  
OS  
45µA, 1MHz, 1mV V , 2.1V to 5.5V Supply  
OS  
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments  
semiconductor products and disclaimers thereto appears at the end of this data sheet.  
All trademarks are the property of their respective owners.  
ꢀꢁ ꢂ ꢃꢄ ꢅ ꢆꢇ ꢂꢈ ꢃ ꢉꢆꢉ ꢊꢋ ꢌꢍ ꢎ ꢏꢐ ꢑꢊꢍꢋ ꢊꢒ ꢓꢔ ꢎ ꢎ ꢕꢋꢑ ꢐꢒ ꢍꢌ ꢖꢔꢗ ꢘꢊꢓ ꢐꢑꢊ ꢍꢋ ꢙꢐ ꢑꢕꢚ ꢀꢎ ꢍꢙꢔ ꢓꢑꢒ  
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ꢀꢎ ꢍ ꢙꢔꢓ ꢑ ꢊꢍ ꢋ ꢖꢎ ꢍ ꢓ ꢕ ꢒ ꢒ ꢊꢋ ꢟ ꢙꢍ ꢕ ꢒ ꢋꢍꢑ ꢋꢕ ꢓꢕ ꢒꢒ ꢐꢎ ꢊꢘ ꢞ ꢊꢋꢓ ꢘꢔꢙ ꢕ ꢑꢕ ꢒꢑꢊ ꢋꢟ ꢍꢌ ꢐꢘ ꢘ ꢖꢐ ꢎ ꢐꢏ ꢕꢑꢕ ꢎ ꢒꢚ  
Copyright 2005, Texas Instruments Incorporated  
www.ti.com  
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SBOS347A − NOVEMBER 2005 − REVISED DECEMBER 2005  
www.ti.com  
This integrated circuit can be damaged by ESD. Texas  
Instruments recommends that all integrated circuits be  
(1)  
ABSOLUTE MAXIMUM RATINGS  
handledwith appropriate precautions. Failure to observe  
proper handling and installation procedures can cause damage.  
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7V  
(2)  
Signal Input Terminals, Voltage  
. . . . . . . . . −0.5V to (V+) + 0.5V  
(2)  
Current . . . . . . . . . . . . . . . . . . . . 10mA  
. . . . . . . . . . . . . . . . . . . . . . . . . . Continuous  
ESD damage can range from subtle performance degradation to  
complete device failure. Precision integrated circuits may be more  
susceptible to damage because very small parametric changes could  
cause the device not to meet its published specifications.  
(3)  
Output Short-Circuit  
Operating Temperature . . . . . . . . . . . . . . . . . . . . . −40°C to +125°C  
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . −65°C to +150°C  
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +150°C  
ESD Rating  
ORDERING INFORMATION(1)  
PACKAGE  
DESIGNATOR  
PACKAGE  
MARKING  
Human Body Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2000V  
Charged Device Model . . . . . . . . . . . . . . . . . . . . . . . . . . . 1000V  
PRODUCT PACKAGE-LEAD  
(2)  
OPA379  
SC70−5  
SOT23−5  
SO−8  
DCK  
DBV  
D
AYR  
AYQ  
(1)  
(2)  
Stresses above these ratings may cause permanent damage.  
OPA379  
OPA379  
Exposure to absolute maximum conditions for extended periods  
may degrade device reliability. These are stress ratings only, and  
functional operation of the device at these or any other conditions  
beyond those specified is not supported.  
OPA379  
B61  
(2)  
OPA2379  
OPA2379  
SOT23−8  
SO−8  
DCN  
D
OPA2379  
OPA4379  
(2)  
(3)  
Input terminals are diode-clamped to the power-supply rails.  
Input signals that can swing more than 0.5V beyond the supply  
rails should be current-limited to 10mA or less.  
(2)  
OPA4379  
TSSOP−14  
PW  
(1)  
For the most current package and ordering information, see the  
Package Option Addendum at the end of this document, or see  
the TI web site at www.ti.com.  
Short-circuit to ground, one amplifier per package.  
(2)  
Available Q1, 2006.  
PIN CONFIGURATIONS  
OPA379  
OPA379  
OPA379  
NC(1)  
1
2
3
4
8
7
6
5
NC(1)  
V+  
V+  
+IN  
1
2
3
5
4
OUT  
1
2
3
5
4
V+  
V
V
IN  
OUT  
IN  
+IN  
OUT  
NC(1)  
+IN  
IN  
V
(3)  
SC70−5  
(3)  
SOT23−5  
SO−8  
OPA4379  
OPA2379  
OPA2379  
OUT A  
1
2
3
4
5
6
7
14 OUT D  
1
OUT A  
8
V+  
OUT A  
1
2
3
4
8
7
6
5
V+  
IN D  
IN A  
13  
12 +IN D  
2
3
4
IN  
7
6
5
OUT B  
IN A  
OUT B  
+IN A  
V+  
+IN  
IN B  
+IN A  
IN B  
V
11  
10 +IN C  
V
+IN B  
V
+IN B  
+IN B  
(2)(3)  
SOT23−8  
SO−8  
IN B  
OUT B  
9
8
IN C  
OUT C  
NOTES:  
(1)  
(2)  
(3)  
NC denotes no internal connection.  
Pin 1 of the SOT23−8 package is determined by orienting the package marking as shown.  
Available Q1, 2006.  
(3)  
TSSOP−14  
2
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SBOS347A − NOVEMBER 2005 − REVISED DECEMBER 2005  
ELECTRICAL CHARACTERISTICS: V = +1.8V TO +5.5V  
S
Boldface limits apply over the specified temperature range indicated.  
At T = +25°C, R = 25kconnected to V /2, and V  
< (V+) − 1V, unless otherwise noted.  
A
L
S
CM  
OPA379, OPA2379, OPA4379  
PARAMETER  
CONDITIONS  
MIN  
TYP  
MAX  
UNIT  
OFFSET VOLTAGE  
Initial Offset Voltage  
Over −40°C to +125°C  
Drift, −40°C to +85°C  
−40°C to +125°C  
V
V
S
= 5V  
0.4  
1.5  
mV  
mV  
OS  
2
dV /dT  
OS  
1.5  
2.7  
2
µV/°C  
µV/°C  
µV/V  
µV/V  
vs Power Supply  
PSRR  
10  
Over −40°C to +125°C  
20  
INPUT VOLTAGE RANGE  
Common-Mode Voltage Range  
V
(V−) − 0.1 to (V+) + 0.1  
100  
V
CM  
(1)  
Common-Mode Rejection Ratio  
Over −40°C to +85°C  
CMRR  
(V−) < V  
(V−) < V  
(V−) < V  
< (V+) − 1V  
< (V+) − 1V  
< (V+) − 1V  
90  
80  
62  
dB  
dB  
dB  
CM  
CM  
Over −40°C to +125°C  
CM  
INPUT BIAS CURRENT  
Input Bias Current  
I
V
S
= 5V, V < = V /2  
CM  
5
5
50  
50  
pA  
pA  
B
S
Input Offset Current  
I
V = 5V  
S
OS  
INPUT IMPEDANCE  
Differential  
13  
10 || 3  
|| pF  
|| pF  
13  
Common-Mode  
10 || 6  
NOISE  
Input Voltage Noise, f = 0.1Hz to 10Hz  
Input Voltage Noise Density, f = 1kHz  
Input Current Noise Density, f = 1kHz  
2.8  
80  
1
µV  
PP  
nV/Hz  
fA/Hz  
e
n
i
n
OPEN-LOOP GAIN  
Open-Loop Voltage Gain  
Over −40°C to +125°C  
A
OL  
V
= 5V, R = 25k, 100mV < V < (V+) − 100mV  
100  
92  
120  
120  
dB  
dB  
dB  
dB  
S
L
O
V
S
= 5V, R = 25k, 100mV < V < (V+) − 100mV  
L O  
V
= 5V, R = 5k, 500mV < V < (V+) − 500mV  
100  
92  
S
L
O
Over −40°C to +125°C  
V
= 5V, R = 5k, 500mV < V < (V+) − 500mV  
S
L
O
OUTPUT  
Voltage Output Swing from Rail  
Over −40°C to +125°C  
R
= 25kΩ  
= 25kΩ  
= 5kΩ  
5
25  
5
10  
15  
50  
75  
mV  
mV  
mV  
mV  
mA  
L
R
L
R
L
Over −40°C to +125°C  
Short-Circuit Current  
R
= 5kΩ  
L
I
SC  
Capacitive Load Drive  
C
LOAD  
See Typical Characteristics Curve  
Closed-Loop Output Impedance  
Open-Loop Output Impedance  
R
G = 1, f = 1kHz, I = 0  
O
10  
28  
kΩ  
OUT  
R
O
f = 100kHz, I = 0  
O
FREQUENCY RESPONSE  
Gain Bandwidth Product  
Slew Rate  
C
= 30pF  
LOAD  
GBW  
SR  
90  
0.03  
25  
kHz  
V/µs  
µs  
G = +1  
Overload Recovery Time  
Turn-On Time  
V
IN  
S GAIN > V  
S
t
1
ms  
ON  
POWER SUPPLY  
Specified/Operating Voltage Range  
Quiescent Current per Amplifier  
Over −40°C to +125°C  
V
I
1.8  
5.5  
5.5  
10  
V
S
V
S
= 5.5V, I = 0  
2.9  
µA  
µA  
Q
O
TEMPERATURE  
Specified/Operating Range  
Storage Range  
−40  
−65  
+125  
+150  
°C  
°C  
Thermal Resistance  
SC70−5  
q
JA  
250  
200  
150  
°C/W  
°C/W  
°C/W  
SOT23−5  
SOT23−8, TSSOP−14, SO−8  
(1)  
See Typical Characteristic, Common-Mode Rejection Ratio vs Frequency.  
3
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SBOS347A − NOVEMBER 2005 − REVISED DECEMBER 2005  
www.ti.com  
TYPICAL CHARACTERISTICS  
At T = +25°C, V = 5V, R = 25kconnected to V /2, unless otherwise noted.  
A
S
L
S
COMMON−MODE AND  
POWER SUPPLY REJECTION RATIO  
vs FREQUENCY  
OPENLOOP GAIN AND PHASE  
vs FREQUENCY  
120  
100  
80  
60  
40  
20  
0
120  
100  
80  
60  
40  
20  
0
0
30  
PSRR  
+PSRR  
60  
90  
120  
150  
180  
CMRR  
100k  
0.1  
1
10  
100  
1k  
10k  
100k  
0.1  
1
10  
100  
1k  
10k  
Frequency (Hz)  
Frequency (Hz)  
MAXIMUM OUTPUT VOLTAGE  
vs FREQUENCY  
QUIESCENT CURRENT  
vs SUPPLY VOLTAGE  
3.5  
3.0  
2.5  
2.0  
1.5  
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
1k  
10k  
100k  
1.5  
2.0  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
Frequency (Hz)  
Supply Voltage (V)  
OUTPUT VOLTAGE  
vs OUTPUT CURRENT  
SHORT−CIRCUIT CURRENT  
vs SUPPLY VOLTAGE  
2.5  
2.0  
1.5  
1.0  
0.5  
0
25  
20  
15  
10  
5
+ISC  
VS  
=
2.5V  
ISC  
_
_
_
_
+125 C  
+85 C  
+25 C  
40 C  
0.5  
1.0  
1.5  
2.0  
2.5  
0
1
2
3
4
5
6
7
8
9
10  
1.5  
2.0  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
IOUT (mA)  
Supply Voltage (V)  
4
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SBOS347A − NOVEMBER 2005 − REVISED DECEMBER 2005  
TYPICAL CHARACTERISTICS (continued)  
At T = +25°C, V = 5V, R = 25kconnected to V /2, unless otherwise noted.  
A
S
L
S
OFFSET VOLTAGE vs COMMON−MODE VOLTAGE  
vs TEMPERATURE  
OFFSET VOLTAGE  
PRODUCTION DISTRIBUTION  
15000  
Unit 1  
12500  
10000  
7500  
5000  
2500  
0
CMRR Specified Range  
2500  
5000  
7500  
_
40 C  
10000  
12500  
15000  
_
+85 C  
Unit 2  
_
+125 C  
0
1
2
3
4
5
Common−Mode Voltage (V)  
µ
Offset Voltage ( V)  
OFFSET VOLTAGE DRIFT DISTRIBUTION  
OFFSET VOLTAGE DRIFT DISTRIBUTION  
_
_
_
_
( 40 C to +85 C)  
( 40 C to +125 C)  
5
1
2
3
4
5
> 5  
1
2
3
4
> 5  
µ
_
µ
_
Offset Voltage Drift ( V/ C)  
Offset Voltage Drift ( V/ C)  
QUIESCENT CURRENT  
vs TEMPERATURE  
QUIESCENT CURRENT  
PRODUCTION DISTRIBUTION  
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
25  
50  
0
25  
50  
75  
100  
125  
_
Temperature ( C)  
µ
Quiescent Current ( A)  
5
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SBOS347A − NOVEMBER 2005 − REVISED DECEMBER 2005  
www.ti.com  
TYPICAL CHARACTERISTICS (continued)  
At T = +25°C, V = 5V, R = 25kconnected to V /2, unless otherwise noted.  
A
S
L
S
INPUT BIAS CURRENT  
vs TEMPERATURE  
0.1Hz TO 10Hz NOISE  
10000  
1000  
100  
10  
1
0.1  
0.01  
25  
50  
0
25  
50  
75  
100  
125  
2.5s/div  
_
Temperature ( C)  
SMALL−SIGNAL OVERSHOOT  
vs CAPACITIVE LOAD  
NOISE vs FREQUENCY  
60  
50  
40  
30  
20  
10  
0
1000  
100  
10  
G = +1  
G =  
1
10  
100  
1000  
1
10  
100  
1k  
10k  
Capacitive Load (pF)  
Frequency (Hz)  
SMALL−SIGNAL STEP RESPONSE  
LARGE−SIGNAL STEP RESPONSE  
µ
25 s/div  
µ
50 s/div  
6
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SBOS347A − NOVEMBER 2005 − REVISED DECEMBER 2005  
APPLICATION INFORMATION  
The OPA379 family of operational amplifiers minimizes  
power consumption without compromising bandwidth or  
+5V  
IOVERLOAD  
10mA max  
noise.  
Power-supply  
rejection  
ratio  
(PSRR),  
OPA379  
VOUT  
common-mode rejection ratio (CMRR), and open-loop  
VIN  
5k  
gain (A ) typical values are 100dB or better.  
OL  
When designing for ultra-low power, choose system  
components carefully. To minimize current consumption,  
select large-value resistors. Any resistors will react with  
stray capacitance in the circuit and the input capacitance  
of the operational amplifier. These parasitic RC  
combinations can affect the stability of the overall system.  
A feedback capacitor may be required to assure stability  
and limit overshoot or gain peaking.  
Figure 1. Input Current Protection for Voltages  
Exceeding the Supply Voltage  
NOISE  
Although micropower amplifiers frequently have high  
wideband noise, the OPA379 series offer excellent noise  
performance. Resistors should be chosen carefully  
Good layout practice mandates the use of a 0.1µF bypass  
capacitor placed closely across the supply pins.  
because the OPA379 has only 2.8µV of 0.1Hz to 10Hz  
PP  
noise, and 80nV/Hz of wideband noise; otherwise, they  
can become the dominant source of noise.  
OPERATING VOLTAGE  
OPA379 series op amps are fully specified and tested from  
+1.8V to +5.5V. Parameters that vary significantly with  
supply voltage are shown in the Typical Characteristics  
curves.  
CAPACITIVE LOAD AND STABILITY  
Follower configurations with load capacitance in excess of  
30pF can produce extra overshoot (see typical  
characteristic, Small-Signal Overshoot vs Capacitive  
Load) and ringing in the output signal. Increasing the gain  
enhances the ability of the amplifier to drive greater  
capacitive loads. In unity-gain configurations, capacitive  
load drive can be improved by inserting a small (10to  
INPUT COMMON-MODE VOLTAGE RANGE  
The input common-mode voltage range of the OPA379  
family typically extends 100mV beyond each supply rail.  
This rail-to-rail input is achieved using a complementary  
input stage. CMRR is specified from the negative rail to 1V  
below the positive rail. Between (V+) − 1V and (V+) + 0.1V,  
the amplifier operates with higher offset voltage because  
of the transition region of the input stage. See the typical  
characteristic, Offset Voltage vs Common-Mode Voltage.  
20) resistor, R , in series with the output, as shown in  
S
Figure 2. This resistor significantly reduces ringing while  
maintaining DC performance for purely capacitive loads.  
However, if there is a resistive load in parallel with the  
capacitive load, a voltage divider is created, introducing a  
Direct Current (DC) error at the output and slightly  
reducing the output swing. The error introduced is  
proportional to the ratio R /R , and is generally negligible.  
S
L
PROTECTING INPUTS FROM  
OVER-VOLTAGE  
Normally, input currents are 5pA. However, large inputs  
(greater than 500mV beyond the supply rails) can cause  
excessive current to flow in or out of the input pins.  
Therefore, as well as keeping the input voltage below the  
maximum rating, it is also important to limit the input  
current to less than 10mA. This limiting is easily  
accomplished with an input voltage resistor, as shown in  
Figure 1.  
V+  
RS  
VOUT  
OPA379  
10 to  
VIN  
CL  
RL  
20  
Figure 2. Series Resistor in Unity-Gain Buffer  
Configuration Improves Capacitive Load Drive  
7
ꢂꢀꢉꢠ ꢡꢢ  
ꢂꢀꢉꢣ ꢠꢡ ꢢ  
ꢂꢀꢉꢤ ꢠꢡ ꢢ  
SBOS347A − NOVEMBER 2005 − REVISED DECEMBER 2005  
www.ti.com  
1. Selecting R : Select R such that the current through R  
In unity-gain inverter configuration, phase margin can be  
reduced by the reaction between the capacitance at the op  
amp input and the gain setting resistors, thus degrading  
capacitive load drive. Best performance is achieved by  
using smaller valued resistors. However, when large  
valued resistors cannot be avoided, a small (4pF to 6pF)  
capacitor, CFB, can be inserted in the feedback, as shown  
in Figure 3. This configuration significantly reduces  
F
F
F
is approximately 1000x larger than the maximum bias  
current over temperature:  
VREF  
RF +  
ǒ
Ǔ
1000 IBMAX  
1.2V  
+
(
)
1000 100pA  
overshoot by compensating the effect of capacitance, C ,  
IN  
+ 12MW [ 10MW  
(1)  
which includes the amplifier input capacitance and PC  
board parasitic capacitance.  
2. Choose the hysteresis voltage, V . For battery-  
HYST  
monitoring applications, 50mV is adequate.  
3. Calculate R as follows:  
1
CFB  
RF  
VHYST  
50mV  
ǒ Ǔ + 210kW  
ǒ Ǔ+ 10MW  
R1 + RF  
VBATT  
2.4V  
(2)  
4. Select a threshold voltage for V rising (V  
) = 2.0V  
THRS  
RI  
IN  
VIN  
5. Calculate R as follows:  
2
OPA379  
VOUT  
CIN  
1
R2 +  
CL  
V
THRS  
 R  
1
1
ƪǒ  
Ǔ*  
ƫ
*
R
F
V
R
REF  
1
1
1
+ ƪǒ  
Ǔ
2V  
1.2V 210kW  
1
1
*
*
10MW  
Figure 3. Improving Capacitive Load Drive  
BATTERY MONITORING  
210kW  
+ 325kW  
(3)  
6. Calculate R  
: The minimum supply voltage for this  
BIAS  
circuit will be 1.8V. The REF1112 has a current  
requirement of 1.2µA (max). Providing it 2µA of supply  
current assures proper operation. Therefore:  
The low operating voltage and quiescent current of the  
OPA379 series make it an excellent choice for battery  
monitoring applications, as shown in Figure 4. In this  
circuit, VSTATUS will be high as long as the battery voltage  
remains above 2V. A low-power reference is used to set  
the trip point. Resistor values are selected as follows:  
VBATTMIN  
IBIAS  
1.8V  
2mA  
RBIAS  
+
+
+ 0.9MW  
(4)  
RF  
R1  
+IN  
+
IBIAS  
OUT  
OPA379  
VSTATUS  
VBATT  
IN  
RBIAS  
VREF  
R2  
REF1112  
Figure 4. Battery Monitor  
8
ꢂ ꢀꢉ ꢠꢡꢢ  
ꢂ ꢀꢉ ꢣꢠꢡ ꢢ  
ꢂ ꢀꢉ ꢤꢠꢡ ꢢ  
www.ti.com  
SBOS347A − NOVEMBER 2005 − REVISED DECEMBER 2005  
LOW-SIDE CURRENT MONITOR  
WINDOW COMPARATOR  
The micropower OPA379 is well suited for current  
monitoring circuits in applications such as a voltage  
regulator with fold-back current limiting, or a high-current  
power supply with crowbar protection. Figure 5 shows the  
OPA379 monitoring the current in a power-supply return  
path using a 0.1shunt resistor. The NPN transistor, Q1  
(2N2222 or equivalent) is used to generate equal voltages  
at the inverting and noninverting inputs. Therefore, the  
Figure 6 shows the OPA2379 used as a window  
comparator. The threshold limits are set by V and V , with  
H
L
V > V . When V < V , the output of A1 will be low. When  
H
L
IN  
H
V
>V , the output of A2 will be low. Therefore, both op  
IN  
L
amp outputs will be at 0V as long as V is between V and  
IN  
H
V . This results in no current flowing through either diode,  
L
Q1 in cutoff, with the base voltage at 0V, and V  
high.  
forced  
OUT  
voltage drops across R and R are equal, and the current  
1
S
If V falls below V , the output of A2 will be high, current  
IN  
L
flowing through Q1 is directly proportional to the current  
flowing through R . As the load current increases, the  
will flow through D2, and V  
will be low. Likewise, if V  
OUT  
IN  
S
rises above V , the output of A1 will be high, current will  
H
current through Q1 increases, the voltage drop across R  
2
flow through D1, and V  
will be low.  
OUT  
increases, and this decreases the output voltage, V  
shown in Equation (5):  
, as  
OUT  
The window comparator threshold voltages are set as  
follows:  
R2  
R1  
+ GND * ǒ  
Ǔ
VOUT  
  RS   IL  
R2  
R1 ) R2  
VH +  
(6)  
(7)  
2.49kW  
100W  
+ 0V * ǒ  
Ǔ
  0.1W   IL  
R4  
R3 ) R4  
VL +  
+ * 2.49W   IL  
(5)  
3V  
3V  
R1  
R2  
5V  
VH  
A1  
D1(2)  
1/2  
3V  
R2  
2.49k  
OPA2379  
5.1k  
VOUT  
VOUT  
RIN  
(1)  
2k  
10k  
Q1(3)  
Q1  
VIN  
5V  
5.1k  
3V  
3V  
A2  
OPA379  
D2(2)  
R1  
100  
1/2  
R3  
OPA2379  
VL  
RS  
0.1  
R4  
Return to Ground  
IL  
NOTES: (1) RIN protects A1 and A2 from possible excess current flow.  
(2) IN4446 or equivalent diodes.  
(3) 2N2222 or equivalent NPN transistor.  
Figure 5. Low-Side Current Monitor  
Figure 6. OPA2379 as a Window Comparator  
9
PACKAGE OPTION ADDENDUM  
www.ti.com  
4-Mar-2006  
PACKAGING INFORMATION  
Orderable Device  
OPA2379AID  
Status (1)  
ACTIVE  
ACTIVE  
ACTIVE  
ACTIVE  
ACTIVE  
ACTIVE  
ACTIVE  
ACTIVE  
Package Package  
Pins Package Eco Plan (2) Lead/Ball Finish MSL Peak Temp (3)  
Qty  
Type  
Drawing  
SOIC  
D
8
8
8
8
8
8
8
8
75 Green (RoHS & CU NIPDAU Level-2-260C-1 YEAR  
no Sb/Br)  
OPA2379AIDG4  
OPA2379AIDR  
OPA2379AIDRG4  
OPA379AID  
SOIC  
SOIC  
SOIC  
SOIC  
SOIC  
SOIC  
SOIC  
D
D
D
D
D
D
D
75 Green (RoHS & CU NIPDAU Level-2-260C-1 YEAR  
no Sb/Br)  
2500 Green (RoHS & CU NIPDAU Level-2-260C-1 YEAR  
no Sb/Br)  
2500 Green (RoHS & CU NIPDAU Level-2-260C-1 YEAR  
no Sb/Br)  
75 Green (RoHS & CU NIPDAU Level-2-260C-1 YEAR  
no Sb/Br)  
OPA379AIDG4  
OPA379AIDR  
75 Green (RoHS & CU NIPDAU Level-2-260C-1 YEAR  
no Sb/Br)  
2500 Green (RoHS & CU NIPDAU Level-2-260C-1 YEAR  
no Sb/Br)  
OPA379AIDRG4  
2500 Green (RoHS & CU NIPDAU Level-2-260C-1 YEAR  
no Sb/Br)  
(1) The marketing status values are defined as follows:  
ACTIVE: Product device recommended for new designs.  
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.  
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in  
a new design.  
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.  
OBSOLETE: TI has discontinued the production of the device.  
(2)  
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check  
http://www.ti.com/productcontent for the latest availability information and additional product content details.  
TBD: The Pb-Free/Green conversion plan has not been defined.  
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements  
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered  
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.  
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and  
package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS  
compatible) as defined above.  
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame  
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)  
(3)  
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder  
temperature.  
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is  
provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the  
accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take  
reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on  
incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited  
information may not be available for release.  
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI  
to Customer on an annual basis.  
Addendum-Page 1  
IMPORTANT NOTICE  
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enhancements, improvements, and other changes to its products and services at any time and to discontinue  
any product or service without notice. Customers should obtain the latest relevant information before placing  
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TI warrants performance of its hardware products to the specifications applicable at the time of sale in  
accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI  
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