The INA217 device is a low-noise, low-distortion, monolithic instrumentation amplifier. Current-feedback circuitry allows the INA217 device to achieve wide bandwidth and excellent dynamic response over a wide range of gain. The INA217 device is ideal for low-level audio signals such as balanced low-impedance microphones. Many industrial, instrumentation, and medical applications also benefit from its low noise and wide bandwidth.
Unique distortion cancellation circuitry reduces distortion to extremely low levels, even in high gain. The INA217 device provides near-theoretical noise performance for 200-Ω source impedance. The INA217 device features differential input, low noise, and low distortion that provides superior performance in professional microphone amplifier applications.
The INA217device features wide supply voltage, excellent output voltage swing, and high output current drive, making it an optimal candidate for use in high-level audio stages.
The INA217 device is available in the same DIP-8 and SOL-16 wide body packages and pinouts as the SSM2017. For a smaller package, see the INA163 device in SO-14 narrow. The INA217 device is specified over the temperature range of –40°C to 85°C.
PART NUMBER | PACKAGE | BODY SIZE (NOM) |
---|---|---|
INA217 | SOIC (16) | 10.30 mm × 7.50 mm |
PDIP (8) | 9.81 mm × 6.35 mm |
Changes from B Revision (February 2005) to C Revision
PIN | I/O | DESCRIPTION | |
---|---|---|---|
NAME | NO. | ||
PDIP | |||
NC | 1 | — | No internal connection |
RG1 | 2 | I | Gain setting pin, for gains greater than one, connect an external resistor between pins 2 and 15 |
NC | 3 | — | No internal connection |
VIN– | 4 | I | Inverting input |
VIN+ | 5 | I | Non-inverting input |
NC | 6 | — | No internal connection |
V– | 7 | I | negative power supply |
NC | 8 | — | No internal connection |
NC | 9 | — | No internal connection |
REF | 10 | I | Reference input |
VOUT | 11 | O | Output |
NC | 12 | — | No internal connection |
V+ | 13 | I | Positive power supply |
NC | 14 | — | No internal connection |
RG2 | 15 | I | Gain setting pin, for gains greater than one, connect an external resistor between pins 2 and 15 |
NC | 16 | — | No internal connection |
SOIC | |||
RG1 | 1 | I | Gain setting pin, for gains greater than one, connect an external resistor between pins 1 and 8 |
VIN– | 2 | I | Inverting input |
VIN+ | 3 | I | Non-inverting input |
V– | 4 | I | negative power supply |
REF | 5 | I | Reference input |
VOUT | 6 | O | Output |
V+ | 7 | I | Positive power supply |
RG2 | 8 | I | Gain setting pin, for gains greater than one, connect an external resistor between pins 2 and 15 |
MIN | MAX | UNIT | |||
---|---|---|---|---|---|
V+ to V– | Supply voltage | ±18 | V | ||
Signal input terminals | Voltage(2) | (V–) – 0.5 | (V+) + 0.5 | V | |
Current(2) | 10 | mA | |||
Output short circuit(3) | Continuous | ||||
Operating temperature | –55 | 125 | °C | ||
Junction temperature | 300 | °C | |||
Tstg | Storage temperature | –55 | 150 | °C |
VALUE | UNIT | |||
---|---|---|---|---|
V(ESD) | Electrostatic discharge | Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) | ±4000 | V |
Charged-device model (CDM), per JEDEC specification JESD22-C101(2) | ±1000 |
MIN | NOM | MAX | UNIT | ||
---|---|---|---|---|---|
V+ to V– | Supply voltage | ±4.5 | ±15 | ±18 | V |
TA | Ambient Temperature | -40 | 25 | 85 | °C |
THERMAL METRIC(1) | INA217 | UNIT | ||
---|---|---|---|---|
DW (SOIC) | P (PDIP) | |||
16 PINS | 8 PINS | |||
RθJA | Junction-to-ambient thermal resistance | 64.3 | 46.2 | °C/W |
RθJC(top) | Junction-to-case (top) thermal resistance | 24.9 | 34.5 | °C/W |
RθJB | Junction-to-board thermal resistance | 29.4 | 23.5 | °C/W |
ψJT | Junction-to-top characterization parameter | 3.3 | 11.7 | °C/W |
ψJB | Junction-to-board characterization parameter | 28.8 | 23.3 | °C/W |
RθJC(bot) | Junction-to-case (bottom) thermal resistance | N/A | N/A | °C/W |
PARAMETER | TEST CONDITIONS | TA = 25°C | UNIT | |||
---|---|---|---|---|---|---|
MIN | TYP | MAX | ||||
GAIN EQUATION(1) | G = 1 + 10k/RG | |||||
Range | 1 to 10000 | V/V | ||||
Gain Error | G = 1 | ±0.1% | ±0.25% | |||
G = 10 | ±0.2% | ±0.7% | ||||
G = 100 | ±0.2% | |||||
G = 1000 | ±0.5% | |||||
GAIN TEMPERATURE DRIFT COEFFICIENT | ||||||
G = 1 | TA = –40°C to 85°C | ±3 | ±10 | ppm/°C | ||
G > 10 | TA = –40°C to 85°C | ±40 | ±100 | ppm/°C | ||
Nonlinearity | G = 1 | ±0.0003 | % of FS | |||
G = 100 | ±0.0006 | % of FS | ||||
INPUT STAGE NOISE | ||||||
Voltage Noise | fO = 1 kHz | RSOURCE = 0 Ω | 1.3 | nV/√Hz | ||
fO = 100 Hz | 1.5 | nV/√Hz | ||||
fO = 10 Hz | 3.5 | nV/√Hz | ||||
Current Noise, | fO = 1 kHz | 0.8 | pA/√Hz | |||
OUTPUT STAGE NOISE | ||||||
Voltage Noise, | fO = 1 kHz | 90 | nV/√Hz | |||
INPUT OFFSET VOLTAGE | ||||||
Input Offset Voltage | VCM = VOUT = 0 V | 50 + 2000/G | 250 + 5000/G | µV | ||
vs Temperature | TA = –40°C to 85°C | 1 + 20/G | µV/°C | |||
vs Power Supply | VS = ±4.5 V to ±18 V | 1 + 50/G | 3 + 200/G | µV/V | ||
INPUT VOLTAGE RANGE | ||||||
Common-Mode Voltage Range | VIN+ – VIN– = 0V | (V+) – 4 | (V+) – 3 | V | ||
VIN+ – VIN– = 0V | (V–) + 4 | (V–) + 3 | V | |||
Common-Mode Rejection | G = 1 | VCM = ±11 V, RSRC = 0 Ω | 70 | 80 | dB | |
G = 100 | 100 | 116 | dB | |||
INPUT BIAS CURRENT | ||||||
Initial Bias Current | 2 | 12 | µA | |||
vs Temperature | TA = –40°C to 85°C | 10 | nA/°C | |||
Initial Offset Current | 0.1 | 1 | µA | |||
vs Temperature | TA = –40°C to 85°C | 0.5 | nA/°C | |||
INPUT IMPEDANCE | ||||||
Differential | 60 || 2 | MΩ || pF | ||||
Common-Mode | 60 || 2 | MΩ || pF | ||||
DYNAMIC RESPONSE | ||||||
Bandwidth, Small Signal, –3d B | ||||||
G = 1 | 3.4 | MHz | ||||
G = 100 | 800 | kHz | ||||
Slew Rate | 15 | V/µs | ||||
THD+Noise, f = 1 kHz | G = 100 | 0.004% | ||||
Settling Time | 0.1% | G = 100, 10V Step | 2 | µs | ||
0.01% | G = 100, 10V Step | 3.5 | µs | |||
Overload Recovery | 50% Overdrive | 1 | µs | |||
OUTPUT | ||||||
Voltage | RL to GND | (V+) – 2 (V–) + 2 |
(V+) – 1.8 (V–) + 1.8 |
V V |
||
Load Capacitance Stability | 1000 | pF | ||||
Short Circuit Current | Continuous-to-Common | ±60 | mA | |||
POWER SUPPLY | ||||||
Rated Voltage | ±15 | V | ||||
Voltage Range | ±4.5 | ±18 | V | |||
Current, Quiescent | IO = 0 mA | ±10 | ±12 | mA | ||
TEMPERATURE RANGE | ||||||
Specification | –40 | 85 | °C | |||
Operating | –40 | 125 | °C |
G = 1 |
G = 1 |
G = 100 |
G = 100 |
The INA217 is a classical three-amp instrumentation amplifier designed for audio applications. Featuring low noise and low distortion the INA217 is ideally suited for amplifying low level audio signals. With a wide supply voltage, wide output voltage swing, and high output current drive the INA217 is also ideally suited for processing high level audio signals. Specified from –40°C to 85°C the INA217 is well suited for industrial applications.
Figure 13 shows the basic connections required for operation. Power supplies should be bypassed with 0.1-μF tantalum capacitors near the device pins. The output Reference (pin 5) should be a low-impedance connection. Resistance of a few Ωs in series with this connection will degrade the common-mode rejection of the INA217.
Gain is set with an external resistor, RG, as shown in Figure 13. The two internal 5-kΩ feedback resistors are laser-trimmed to 5-kΩ within approximately ±0.2%. Equation 1 shows the gain equation for the INA217.
The temperature coefficient of the internal 5-kΩ resistors is approximately ±25 ppm/°C. Accuracy and TCR of the external RG will also contribute to gain error and temperature drift. These effects can be inferred from the gain equation. Make a short, direct connection to the gain set resistor, RG. Avoid running output signals near these sensitive input nodes.
The INA217 provides very low noise with low-source impedance. Its 1.3-nV/√Hz voltage noise delivers near-theoretical noise performance with a source impedance of 200 Ω. The input stage design used to achieve this low noise results in relatively high input bias current and input bias current noise. As a result, the INA217 may not provide the best noise performance with a source impedance greater than 10 kΩ. For source impedance greater than 10 kΩ, other instrumentation amplifiers may provide improved noise performance.
Very low source impedance (less than 10 Ω) can cause the INA217 to oscillate. This depends on circuit layout, signal source, and input cable characteristics. An input network consisting of a small inductor and resistor, as shown in Figure 14, can greatly reduce any tendency to oscillate. This is especially useful if a variety of input sources are to be connected to the INA217. Although not shown in other figures, this network can be used as needed with all applications shown.
A variable voltage applied to pin 5, as shown in Figure 15, can be used to adjust the output offset voltage. A voltage applied to pin 5 is summed with the output signal. An operational amplifier connected as a buffer is used to provide a low impedance at pin 5 to assure good common-mode rejection.
The INA217 has a single functional mode of operation. The mode is operational when the power supply voltage exceeds ±4.5 V. The maximum power supply voltage is ±18 V. The INA217 is specified over the temperature range from –40°C to 85°C and is operational to 125°C.
NOTE
Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.
The INA217 is used in professional audio equipment such as professional microphone preamps, moving-coil transducer amplifiers, differential receivers, and bridge transducer amplifiers.
Figure 16 shows a typical circuit for a professional microphone input amplifier.
R1 and R2 provide a current path for conventional 48-V phantom power source for a remotely located microphone. An optional switch allows phantom power to be disabled. C1 and C2 block the phantom power voltage from the INA217 input circuitry. Non-polarized capacitors should be used for C1 and C2 if phantom power is to be disabled. For additional input protection against ESD and hot-plugging, four IN4148 diodes may be connected from the input to supply lines.
R4 and R5 provide a path for input bias current of the INA217. Input offset current (typically 100 nA) creates a DC differential input voltage that will produce an output offset voltage. This is generally the dominant source of output offset voltage in this application. With a maximum gain of 1000 (60 dB), the output offset voltage can be several volts. This may be entirely acceptable if the output is AC-coupled into the subsequent stage. An alternate technique is shown in Figure 16. An inexpensive FET-input operational amplifier in a feedback loop drives the DC output voltage to 0 V. A2 is not in the audio signal path and does not affect signal quality.
Gain is set with a variable resistor, R7, in series with R6. R6 determines the maximum gain. The total resistance, R6 + R7, determines the lowest gain. A special reverse-log taper potentiometer for R7 can be used to create a linear change (in dB) with rotation.
The INA217 is specified for operation from ±4.5 V to ±18 V; many specifications apply from –40°C to 85°C. Parameters that can exhibit significant variance with regard to operating voltage or temperature are presented in the Typical Characteristics.