Datasheet

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INA117

FEATURES

● COMMON-MODE INPUT RANGE:

±200V (V

= ±15V)

● PROTECTED INPUTS:

±500V Common-Mode

±500V Differential

● UNITY GAIN: 0.02% Gain Error max

● NONLINEARITY: 0.001% max

● CMRR: 86dB min

APPLICATIONS

● CURRENT MONITOR

● BATTERY CELL-VOLTAGE MONITOR

● GROUND BREAKER

● INPUT PROTECTION

● SIGNAL ACQUISITION IN NOISY

ENVIRONMENTS

● FACTORY AUTOMATION

DESCRIPTION

The INA117 is a precision unity-gain difference

amplifier with very high common-mode input voltage

range. It is a single monolithic IC consisting of a

precision op amp and integrated thin-film resistor

network. It can accurately measure small differential

voltages in the presence of common-mode signals up

to ±200V. The INA117 inputs are protected from

momentary common-mode or differential overloads

up to ±500V.

In many applications, where galvanic isolation is not

essential, the INA117 can replace isolation amplifiers.

This can eliminate costly isolated input-side power

supplies and their associated ripple, noise and quies-

cent current. The INA117’s 0.001% nonlinearity and

200kHz bandwidth are superior to those of conven-

tional isolation amplifiers.

The INA117 is available in 8-pin plastic mini-DIP and

SO-8 surface-mount packages, specified for the –40°C

to +85°C temperature range. The metal TO-99 models

are available specified for the –40°C to +85°C and

–55°C to +125°C temperature range.

High Common-Mode Voltage

DIFFERENCE AMPLIFIER

Ref

–In

+In

V–

Comp

V+

Ref

21.11kΩ

380kΩ

20kΩ

INA117

www.ti.com

Summary of content (17 pages)

PAGE 1
INA117 INA 117 INA 117 www.ti.com High Common-Mode Voltage DIFFERENCE AMPLIFIER FEATURES APPLICATIONS ● COMMON-MODE INPUT RANGE: ±200V (VS = ±15V) ● PROTECTED INPUTS: ±500V Common-Mode ±500V Differential ● UNITY GAIN: 0.02% Gain Error max ● NONLINEARITY: 0.
PAGE 2
SPECIFICATIONS At TA = +25°C, VS = ±15V, unless otherwise noted. INA117AM, SM PARAMETER CONDITIONS MIN GAIN Initial (1) Error vs Temperature Nonlinearity (2) OUTPUT Rated Voltage Rated Current Impedance Current Limit Capacitive Load IO = +20mA, –5mA VO = 10V To Common Stable Operation INPUT Impedance Differential Common-Mode Differential Common-Mode, Continuous Voltage Range Common-Mode Rejection DC AC, 60Hz vs Temperature, DC AM, BM, P, KU SM 10 +20, –5 INA117BM TYP MAX 1 0.01 2 0.0002 0.
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PIN CONFIGURATION Top View TO-99 INA117AM, BM, SM Tab 8 Ref B –In Top View DIP/SO INA117P, KU Comp 1 7 V+ 2 6 3 RefB 1 8 Comp –In 2 7 V+ +In 3 6 Output V– 4 5 RefA Output 5 Ref A +In 4 V– Case internally connected to V–. Make no connection. ELECTROSTATIC DISCHARGE SENSITIVITY ABSOLUTE MAXIMUM RATINGS Supply Voltage .................................................................................. ±22V Input Voltage Range, Continuous .........................................
PAGE 4
TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, unless otherwise noted.
PAGE 5
TYPICAL PERFORMANCE CURVES (Cont.) At TA = +25°C, VS = ±15V, unless otherwise noted.
PAGE 6
APPLICATION INFORMATION Figure 1 shows the basic connections required for operation. V– Applications with noisy or high-impedance power-supply lines may require decoupling capacitors close to the device pins. V+ 4 The output voltage is equal to the differential input voltage between pins 2 and 3. The common mode input voltage is rejected. 2 V2 Internal circuitry connected to the compensation pin 8 cancels the parasitic distributed capacitance between the feedback resistor, R2, and the IC substrate.
PAGE 7
MEASURING CURRENT The INA117 can be used to measure a current by sensing the voltage drop across a series resistor, RS. Figure 4 shows the INA117 used to measure the supply currents of a device under test. The circuit in Figure 5 measures the output current of a power supply. If the power supply has a sense connection, it can be connected to the output side of RS to eliminate the voltage-drop error. Another common application is current-to-voltage conversion, as shown in Figure 6.
PAGE 8
VS (±200V max) 2 380kΩ 380kΩ RS 250Ω 3 250Ω RC* 4 to 20mA 6 380kΩ VO = 1V to 5V 21.1kΩ 8 20kΩ 1 5 VS (a) (±200V max) *Not needed if RS is less than 20Ω—see text. 2 380kΩ 380kΩ 250Ω RC * RS 250Ω 3 6 380kΩ VO = –1V to –5V 4 to 20mA 21.1kΩ 8 20kΩ 1 5 (b) 4 to 20mA 2 380kΩ 380kΩ *Not needed if RS is less than 20Ω—see text. 250Ω RC * RS 250Ω 3 6 380kΩ VO = 1V to 5V 20kΩ 21.1kΩ 8 VS 1 5 (±200V max) 4 to 20mA (c) *Not needed if RS is less than 20Ω—see text.
PAGE 9
Example: For a 1V/mA transfer function, the nominal, uncorrected value for RS would be 1kΩ. A slightly larger value, RS' = 1002.6Ω, compensates for the gain error due to loading. In all cases, the sense resistor imbalances the input resistor matching of the INA117, degrading its CMR. Also, the input impedance of the INA117 loads RS, causing gain error in the voltage-to-current conversion. Both of these errors can be easily corrected.
PAGE 10
Figure 8 shows very high input impedance buffer used to measure low leakage currents. Here, the buffer op amp is powered with an isolated, split-voltage power supply. Using an isolated power supply allows full ±200V common-mode input range. these resistors produces approximately 550nV/√Hz noise. The internal op amp contributes virtually no excess noise at frequencies above 100Hz. Many applications may be satisfied with less than the full 200kHz bandwidth of the INA117.
PAGE 11
V2 380kΩ 2 380kΩ V– V+ 4 V3 6 380kΩ 3 VO = 1+ 19 R7 380kΩ 2 V2 R6 21.1kΩ 7 V3 – V 2 380kΩ 20kΩ INA117 8 1 5 R7 V3 R6 6 380kΩ 3 VO = V3 – V2 + VX 21.1kΩ OPA27 Refer to Application Bulletin AB-001 for details. GAIN (V/V) R7 (kΩ) R6 (kΩ) 1/2 1/4 1/5 1.05 3.16 4.22 20 20 20 20kΩ INA117 8 1 5 OPA27 VX FIGURE 11. Summing VX in Output. FIGURE 10. Reducing Differential Gain. V2 2 R1 380kΩ 3 R3 380kΩ Refer to Application Bulletin AB-010 for details.
PAGE 12
+9V 7 2 V2 380kΩ 380kΩ 7 VCM Range = +50V to +200V (VS ±9V) 3 V3 21.1kΩ (a) 2 6 380kΩ 25kΩ 25kΩ 5 6 20kΩ VO = V3 – V2 INA117 8 1 5 4 3 25kΩ –3V > VO > –6V swap A2 pins 2 and 3 for +4V > VO > 3V. INA105 25kΩ 1 4 –9V +9V 7 2 V2 380kΩ 380kΩ 7 VCM Range = –12V to +200V (VS = ±9V) 3 V3 6 380kΩ 2 25kΩ 25kΩ 5 6 21.1kΩ (b) INA117 8 VO = V3 – V2 20kΩ 1 5 4 3 25kΩ 25kΩ 1N4684 3.3V (V–) +3.3V 0V > VO > –6V swap A2 pins 2 and 3 for +4V > VO > 0V.
PAGE 13
+200V max V– V+ 4 2 7 380kΩ 380kΩ + – 3 6 380kΩ 21.1kΩ 20kΩ INA117 8 1 5 V– V+ 4 2 7 380kΩ 380kΩ + 6 – 3 380kΩ 21.1kΩ 20kΩ INA117 Repeat for each cell 8 1 eO = Cell Voltage 5 MUX V– V+ 4 2 7 380kΩ 380kΩ + – 3 6 380kΩ 21.1kΩ 20kΩ INA117 8 1 5 Cell Select V– V+ 4 2 7 380kΩ 380kΩ + – 3 6 380kΩ 21.1kΩ 20kΩ INA117 8 1 5 –200V max FIGURE 14. Battery Cell Voltage Monitor.
PAGE 14
VS (200V max) +15V –15V 7 2 4 380kΩ 380kΩ R1 0.1Ω 3 6 380kΩ –0.1 (I1) I1 20kΩ 21.1kΩ INA117 8 1 Load A1 VIN 5 ILOAD = I1 – I2 +15V 7 +15V –15V 7 4 –15V 4 I2 2 380kΩ 100kΩ 380kΩ 2 R2 0.1Ω 5 10kΩ 6 6 3 380kΩ 3 –0.1 (I2) 10kΩ VO VO = I 1 – I2 = ILOAD 100kΩ 21.1kΩ INA106 20kΩ 1 INA117 8 1 5 VS (–200V max) FIGURE 15. Measuring Amplifier Load Current. V2 V3 2 3 R1 380kΩ R2 380kΩ R3 380kΩ 6 VOUT = V3 – V2 R5 21.1kΩ R4 20kΩ INA117 8 1 5 C1 R1 0.
PAGE 15
PACKAGE OPTION ADDENDUM www.ti.
PAGE 16
PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 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.
PAGE 17
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.