INA165x-Q1 SoundPlus™ 高共模抑制线路接收器

1 特性

• 符合面向汽车应用的 AEC-Q100 标准
  • 温度等级 1：–40°C 至 +125°C，T_A
• 高共模抑制：91dB（典型值）
• 高输入阻抗：1MΩ 差分
• 超低噪声：-104.7dBu，未加权
• 超低总谐波失真 + 噪声：
  -119dB THD+N（20dBu，22kHz 带宽）
• 短路保护
• 集成电磁干扰 (EMI) 滤波器
• 宽电源电压范围：±2.25V 至 ±12V
• 采用小型 14 引脚 TSSOP 封装

2 应用

• 车厢麦克风前置放大器
• 信息娱乐系统
• 音频输入电路
• 线路驱动器
• 外部音频功率放大器

简化内部原理图

3 说明

INA1650-Q1 双通道和 INA1651-Q1 单通道 (INA165x-Q1) SoundPlus™音频线路接收器可实现 91dB 的极高共模抑制比 (CMRR)，与此同时，对于 20dBu 信号电平，可在 1kHz 时保持 -119dB 的超低 THD+N。不同于其他线路接收器产品，INA165x-Q1 CMRR 在额定温度范围内能保持特性不变，经生产测试，可在各种应用中提供稳定的 性能。

INA165x-Q1 器件支持 ±2.25V 至 ±12V 的极宽电源电压范围。除线路接收器通道以外，INA165x-Q1 还包含一个缓冲 1/2 Vs 基准输出，因此可配置为用于双电源或单电源 应用。1/2 Vs 输出可用作信号链中的另一个模拟电路的偏置电压。

INA1650-Q1 具有 独特的内部布局，即使在过驱或过载条件下也可在通道间实现最低串扰和零交互。

1. 如需了解所有可用封装，请参阅数据表末尾的封装选项附录。

CMRR 直方图（5746 通道）

4 修订历史记录

Changes from B Revision (April 2019) to C Revision

• Changed ESD Ratings table to show individual device ratings Go

Changes from A Revision (October 2017) to B Revision

• Added 向数据表中添加了 INA1651-Q1 器件和相关内容Go

Changes from * Revision (August 2017) to A Revision

• INA1650-Q1 的建议电源电压范围从 36V 降到了 24V。文本、图表和电路图中提及的所有 36V 工作电压都已删除或修改，以反映 24V 的最大电源电压。Go

5 Pin Configuration and Functions

6 Specifications

6.1 Absolute Maximum Ratings

6.2 ESD Ratings

6.3 Recommended Operating Conditions

6.4 Thermal Information

6.5 Electrical Characteristics:

6.6 Typical Characteristics

5746 channels

VREF pins connected to ground

Figure 1. Common-Mode Rejection Ratio Distribution

5746 channels

Figure 3. Distribution of Mismatch in 500-kΩ Input Resistors

5746 channels

Figure 5. Offset Voltage Distribution

Figure 7. Frequency Response

Figure 9. Common-Mode Rejection Ratio vs Frequency

Figure 11. Voltage Noise Spectral Density

3 VRMS, 500-kHz measurement bandwidth

Figure 13. THD+N vs Frequency

SMPTE 4:1 60 Hz and 7 kHz, 90-kHz measurement bandwidth

Figure 15. SMPTE Intermodulation Distortion vs Output Amplitude

Figure 17. Signal Path Output Impedance vs Frequency

100-mV input step

Figure 19. Overshoot vs Capacitive Load

10-mV input step

Figure 21. Small-Signal Step Response

10-V input step, 0.01% settling = ±1 mV

Figure 23. Rising-Edge Settling Time

Figure 25. No Phase Reversal

5 typical units

Figure 27. Output Offset Voltage vs Common-Mode Voltage

Figure 29. Positive Output Voltage vs Output Current

Figure 31. Quiescent Current vs Power Supply Voltage

REF A/B connected to 0 V

Figure 33. Input Common-Mode Voltage vs Output Voltage

REF A/B connected to VMID(OUT)

Figure 35. Input Common-Mode Voltage vs Output Voltage

REF A/B connected to 0 V

Figure 37. Input Common-Mode Voltage vs Output Voltage

5746 channels

VREF pins connected to VMID(OUT)

Figure 2. Common-Mode Rejection Ratio Distribution

5746 channels

Figure 4. Gain Error Distribution

52 channels

Figure 6. Offset Voltage Drift Distribution

Figure 8. Maximum Output Voltage vs Frequency

Figure 10. Power Supply Rejection Ratio vs Frequency

3 VRMS, 90-kHz measurement bandwidth

Figure 12. THD+N vs Frequency

1 kHz, 90-kHz measurement bandwidth

Figure 14. THD+N vs Output Amplitude

CCIF 19 kHz and 20 kHz, 90-kHz measurement bandwidth

Figure 16. CCIF Intermodulation Distortion vs Output Amplitude

CF = 1 µF

Figure 18. Supply Divider Output Impedance vs Frequency

Figure 20. Channel Separation vs Frequency

10-V input step

Figure 22. Large-Signal Step Response

10-V input step, 0.01% settling = ±1 mV

Figure 24. Falling-Edge Settling Time

5 typical units

Figure 26. CMRR vs Temperature

Figure 28. Short-Circuit Current vs Temperature

Figure 30. Negative Output Voltage vs Output Current

Figure 32. Quiescent Current vs Temperature

REF A/B connected to 0 V

Figure 34. Input Common-Mode Voltage vs Output Voltage

REF A/B connected to VMID(OUT)

Figure 36. Input Common-Mode Voltage vs Output Voltage

REF A/B connected to 0 V

Figure 38. Input Common-Mode Voltage vs Output Voltage

7 Detailed Description

7.1 Overview

The INA165x-Q1 family combines high-performance audio operational amplifier cores with high-precision resistor networks to provide exceptional audio performance and rejection of noise that may be externally coupled into the audio signal path. The two line-receiver channels of the INA1650-Q1, and the single line receiver channel of the INA1651-Q1, use an instrumentation amplifier topology with a fixed unity gain to provide high input impedance and a high common-mode rejection ratio (CMRR). Unlike other line receiver products that use a simple four-resistor difference amplifier topology, the INA165x-Q1 topology provides excellent CMRR even with mismatched source impedances.

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Audio Signal Path

Figure 39 highlights the basic elements present in the audio signal pathway of the INA165x-Q1 line receivers. The primary elements are input biasing resistors, electromagnetic interference (EMI) filtering, input buffers, and a difference amplifier. The primary role of an audio line receiver is to convert a differential input signal into a single-ended output signal while rejecting noise that is common to both inputs (common-mode noise). The difference amplifier (which consists of an op amp and four matched 10-kΩ resistors) accomplishes this task. The basic transfer function of the circuit is shown in Equation 1:

Equation 1.

Figure 39. INA165x-Q1 Audio Signal Path (Single Channel Shown)

The input buffers prevent external resistances (such as those from the PCB, connectors, or cables) from ruining the precise matching of the internal 10-kΩ resistors that degrade the high common-mode rejection of the difference amplifier. As is typical of many amplifiers, a small bias current flows into or out of the buffer amplifier inputs. This current must flow to a common potential for the buffer to function properly. The input biasing resistors provide an internal pathway for this current to the COM pin. The COM pin connects to ground in a dual-supply system, or to the output of the internal supply divider, VMID(OUT), in single-supply applications. Finally, EMI filtering is added to the input buffers to prevent high-frequency interference signals from propagating through the audio signal pathway.

7.3.2 Supply Divider

The INA165x-Q1 have an integrated supply-divider circuit that biases the input common-mode voltage and output reference voltage to the halfway point between the applied power supply voltages. The nominal output voltage of the supply divider circuit is shown in Equation 2:

Equation 2.

Figure 40 illustrates the internal topology of the supply-divider circuit. The supply divider consists of two 500-kΩ resistors connected between the VCC and VEE pins of the INA165x-Q1. The noninverting input of a buffer amplifier is connected to the midpoint of the voltage divider that is formed by the 500-kΩ resistors. The buffer amplifier provides a low-impedance output that is required to bias the REF pins without degrading the CMRR. For dual-supply applications where the supply divider circuit is not used, no connection is required for the VMID(IN) or VMID(OUT) pins.

Figure 40. Internal Supply Divider Circuit

7.3.3 EMI Rejection

The INA165x-Q1 use integrated electromagnetic interference (EMI) filtering to reduce the effects of EMI from sources (such as wireless communications) and densely-populated boards with a mix of analog signal-chain and digital components. The INA165x-Q1 devices are specifically designed to minimize susceptibility to EMI by incorporating an internal low-pass filter. Depending on the end-system requirements, additional EMI filters may be required near the signal inputs of the system; as well as incorporating known good practices, such as using short traces, low-pass filters, and damping resistors combined with parallel and shielded signal routing. Texas Instruments developed a method to accurately measure the immunity of an amplifier over a broad frequency spectrum, extending from 10 MHz to 6 GHz. This method uses an EMI rejection ratio (EMIRR) to quantify the ability of the INA165x-Q1 to reject EMI. Figure 41 and Figure 42 show the INA165x-Q1 EMIRR graph for both differential and common-mode EMI rejection across this frequency range. Table 1 shows the EMIRR values for the INA165x-Q1 at frequencies commonly encountered in real-world applications. Applications listed in Table 1 can be centered on or operated near the particular frequency shown.

Figure 41. Common-Mode EMIRR Testing

Figure 42. Differential Mode EMIRR Testing

7.3.4 Electrical Overstress

Designers often ask questions about the capability of an amplifier to withstand electrical overstress. These questions typically focus on the device inputs, but can involve the supply voltage pins or the output pin. Each of these different pin functions have electrical stress limits determined by the voltage breakdown characteristics of the particular semiconductor fabrication process and specific circuits connected to the pin. Additionally, internal electrostatic discharge (ESD) protection is built into these circuits to protect them from accidental ESD events, both before and during product assembly. A good understanding of basic ESD circuitry and the relevance of circuitry to an electrical overstress event is helpful. Figure 43 illustrates the ESD circuits contained in the INA165x-Q1. The ESD protection circuitry involves several current-steering diodes that are connected from the input and output pins, and routed back to the internal power-supply lines. This protection circuitry is intended to remain inactive during normal circuit operation. The input pins of the INA165x-Q1 are protected with internal diodes that are connected to the power-supply rails. These diodes clamp the applied signal to prevent the input circuitry from damage. If the input signal voltage exceeds the power supplies by more than 0.3 V, limit the input signal current to less than 10 mA to protect the internal clamp diodes. A series input resistor can typically limit the current. Some signal sources are inherently current-limited and do not require limiting resistors.

Figure 43. INA165x-Q1 Internal ESD Protection Circuitry
(Single Channel and Supply-Divider Shown for Simplicity)

7.3.5 Thermal Shutdown

If the junction temperature of the INA165x-Q1 exceed approximately 170°C, a thermal shutdown circuit disables the amplifier to protect the device from damage. The amplifier is automatically re-enabled after the junction temperature falls to less than the shutdown threshold temperature. If the condition that caused excessive power dissipation is not removed, the amplifier oscillates between the shutdown and enabled state until the output fault is corrected.

7.4 Device Functional Modes

7.4.1 Single-Supply Operation

The INA165x-Q1 can be used on single power supplies ranging from 4.5 V to 24 V. Use the COM and REF pins to level shift the internal voltages into a linear operating condition. Ideally, connecting the REF and COM pins to a midsupply potential, such as the VMID(OUT) pin, avoids saturating the output of the internal amplifiers.

8 Application and Implementation

8.1 Application Information

8.1.1 Input Common-Mode Range

The linear input voltage range of the INA165x-Q1 input circuitry extends from 350 mV inside the negative supply voltage to 2 V below the positive supply, and maintains 85-dB (minimum) common-mode rejection throughout this range. The INA165x-Q1 operates over a wide range of power supplies and V_REF configurations; providing a comprehensive guide to common-mode range limits for all possible conditions is impractical. The common-mode range for most operating conditions is best calculated using the INA common-mode range calculating tool.

8.1.2 Common-Mode Input Impedance

The high CMRR of many line receivers can degrade by impedance mismatches in the system. Figure 44 shows a common-mode noise source (V_CM) connected to both inputs of a single channel of the INA165x-Q1. An external parasitic resistance (R_EXT) represents the mismatch in impedances between the common-mode noise source and the inputs of the INA165x-Q1. This mismatched impedance may be due to PCB layout, connectors, cabling, passive component tolerances, or the circuit topology. The presence of R_EXT in series with the IN+ input degrades the overall CMRR of the system because the voltage at IN+ is no longer equal to the voltage at IN–. Therefore, a portion of the common-mode noise converts to a differential signal and passes to the output.

Figure 44. A Single Channel of the INA165x-Q1 Shown With Source Impedance Mismatch (R_EXT) and Optional Resistor (R_COM)

While the INA165x-Q1 is significantly more resistant to these effects than typical line receivers, connecting a resistor (R_COM) from the COM pin to the system ground further improves CMRR performance. Figure 45 shows the CMRR of the INA165x-Q1 (typical CMRR of 92 dB) for increasing source impedance mismatches. If the COM pin is connected directly to ground (R_COM equal to 0 Ω), a 20-Ω source impedance mismatch degrades the CMRR from 92 dB to 83.7 dB. However, if R_COM has a value of 1 MΩ, the CMRR only degrades to 89.6 dB, which is an improvement of approximately 6 dB.

Figure 45. CMRR vs Source Impedance Mismatch for Different R_COM Values

R_COM does not need to be a high-precision resistor with a very tight tolerance. Low-cost 5% or 1% resistors can be used with no degradation in overall performance. The addition of R_COM does not increase the noise of the audio signal path.

In single-supply systems where AC coupling is used at the inputs of the INA165x-Q1, adding R_COM lengthens the start-up time of the circuit. The input AC-coupling capacitors are charged to the midsupply voltage through the R_COM resistor, which may take a substantial amount of time if R_COM has a large value (such as 1 MΩ). Do not use R_COM in these systems if start-up time is a concern. In dual-supply systems with input AC-coupling capacitors, the capacitor voltage does not need to be charged to a midsupply point, because the capacitor voltage settles to ground by default. Therefore, R_COM does not increase start-up time in dual-supply systems.

8.1.3 Start-Up Time in Single-Supply Applications

The internal supply divider of the INA165x-Q1 is constructed using two 500-kΩ resistors connected in series between the VCC and VEE pins. These resistors are matched on-chip to provide a reference voltage that is exactly one half of the power supply voltage. Noise from the power supplies and thermal noise from the resistors degrades the overall audio performance of the INA165x-Q1 if allowed to enter the signal path. Therefore, TI recommends a filter capacitor (C_F) is connected to the VMID(IN) pin, as shown in Figure 46 The C_F capacitor forms a low-pass filter with the internal 500-kΩ resistors. Noise above the corner frequency of this filter is passed to ground and is removed from the audio signal path. The corner frequency of the filter is shown in Equation 3:

Equation 3.

Figure 46. Connect a Capacitor (C_F) to the VMID(IN) Pin to Reduce Noise from the Voltage Divider

Figure 47. A Zener Diode (ZD1) Connected to the Positive Supply Can Decrease Start-Up Time

When power is applied to the INA165x-Q1, the filter capacitor (C_F) charges through the internal 500-kΩ resistors. If the C_F capacitor has a large value, the time required for V_MID(OUT) to reach the final midsupply voltage may be extensive. Adding a zener diode from the VMID(IN) pin to the positive power supply (as shown in Figure 47) reduces this time. The zener voltage must be slightly greater than one half of the power supply voltage.

Using large AC-coupling capacitors increases the start-up time of the line receiver circuit in single-supply applications. When power is applied, the AC-coupling capacitors begin to charge to the midsupply voltage applied to the COM pin through a current flowing through the input resistors as shown in Figure 48. The INA165x-Q1 functions properly when the input common-mode voltage (and the capacitor voltage) is within the specified range. The time required for the input common-mode voltage to reach 98% of the final value is shown in Equation 4:

Equation 4.

Figure 48. AC-Coupling Capacitors Charge to the Mid-Supply Voltage Through the Input Resistors

8.1.4 Input AC Coupling

The signal path in most audio systems is typically AC-coupled to avoid the propagation of DC voltages, which can potentially damage loudspeakers or saturate power amplifiers. The capacitor values must be selected to pass the desired bandwidth of audio signals. The high-pass corner frequency is calculated with Equation 5:

Equation 5.

Figure 49. AC-Coupling Capacitors Form a High-Pass Filter With INA165x-Q1 Input Resistors

Although the input resistors of the INA165x-Q1 are matched typically within 0.01%, large capacitors are usually mismatched. The mismatch in the values of the AC-coupling capacitors causes the corner frequencies at the two signal inputs (IN+ and IN–) to be different, which can degrade CMRR at low frequency. For this reason, TI recommends placing the high-pass corner frequency well below the audio bandwidth and to use a resistor in series with the COM pin (R_COM), as shown in Figure 44 if possible. See the Common-Mode Input Impedance section for more information on placing a resistor in series with the COM pin. Figure 50 shows the effect of a 5% mismatch in the values of the input AC-coupling capacitors with and without an R_COM resistor. Comparing CMRR at 100 Hz: 1-µF AC-coupling capacitors with a 5% mismatch degrade the CMRR to 75 dB, while 10-µF capacitors and a 1-MΩ R_COM resistor shows 92 dB of CMRR.

Figure 50. CMRR Degradation Due to a 5% Mismatch in AC-Coupling Capacitors

8.1.5 Supply Divider Capacitive Loading

The VMID(OUT) pin of the INA165x-Q1 is stable with capacitive loads up to 150 pF. An isolation resistor (R_ISO in Figure 51), must be used if capacitive loads larger than 150 pF are connected to the VMID(OUT) pin. Figure 51 shows the recommended configuration of an isolation resistor in series with the capacitive load. The REF pins of the INA165x-Q1 must connect directly to the VMID(OUT) pin before the isolation resistor. Any resistance placed between the VMID(OUT) pin and the reference pins degrades the CMRR of the device. Figure 52 shows the recommended value for the isolation resistor for increasing capacitive loads.

Figure 51. Place an Isolation Resistor Between the VMID(OUT) Pin and Large Capacitive Loads

Figure 52. Recommended Isolation Resistor Value vs Capacitive Load

8.2 Typical Applications

The low noise and distortion of the INA165x-Q1 make the devices an excellent choice for a variety of applications in professional and consumer audio products. However, these same performance metrics make the INA165x-Q1 useful for industrial, test and measurement, and data-acquisition applications. The examples shown here are possible applications where the INA165x-Q1 provides exceptional performance.

8.2.1 Line Receiver for Differential Audio Signals in a Split-Supply System

The INA165x-Q1 are designed to require a minimum number of external components to achieve data sheet-level performance in audio line-receiver applications. Figure 53 shows the INA165x-Q1 used as a differential audio line receiver in split-supply systems that are common in many audio applications. The line receiver recovers a differential audio signal that may have been affected by significant common-mode noise.

Figure 53. INA1650-Q1 Device Used as a Line Receiver for Differential Audio Signals in a Split-Supply System

8.2.1.1 Design Requirements

• Power supply voltage: ±12 V
• Frequency response: < 0.1 dB deviation from 20 Hz to 20 kHz
• Common-mode rejection ratio: > 80 dB at 1 kHz
• THD+N: < –100 dB (4-dBu input signal, 1-kHz fundamental, 90-kHz measurement bandwidth)

8.2.1.2 Detailed Design Procedure

The passive components shown in Figure 53 are selected using the information given in the Application Information and Layout Guidelines sections. All 10-µF input ac-coupling capacitors (C1, C2, C3, and C4) maximize the CMRR performance at low frequency, as shown in Figure 50. The high-pass corner frequency for input signals meets the design requirement for frequency response, as Equation 6 shows:

Equation 6.

The 1-MΩ R_COM resistors (R3 and R4) further improve CMRR performance at low frequency. Resistors R1, R2, R4, and R5 provide a discharge pathway for the ac-coupling capacitors in the event that audio equipment with a dc offset voltage is connected to the inputs of the circuit. These resistors are optional and may degrade the CMRR performance with mismatches in source impedance. Finally, capacitors C5, C6, C7, and C8 provide a low-impedance pathway for power supply noise to pass to ground rather than interfering with the audio signal. No connection is necessary on the VMID(IN) and VMID(OUT) pins because the supply-divider circuit is not used in this particular application.

8.2.1.3 Application Curves

Figure 54 through Figure 59 illustrate the measured performance of the line receiver circuit. Figure 54 shows the measured frequency response. The gain of the circuit is 0 dB as expected with 0.1-dB magnitude variation at 10 Hz. The measured CMRR of the circuit (Figure 55) at 1 kHz equals 94 dB without any source impedance mismatch. Adding a 10-Ω source impedance mismatch degrades the CMRR at 1 kHz to 92 dB. The high-frequency degradation of CMRR shown in Figure 55 for the 10-Ω source impedance mismatch cases is due to the capacitance of the cables used for the measurement. The total harmonic distortion plus noise (THD+N) is plotted over frequency in Figure 56. For a 4-dBu (1.23 V_RMS) input signal level, the THD+N remains flat at –101.6 dB (0.0008%) over the measured frequency range. Increasing the signal level to 20 dBu further decreases the THD+N to –113.2 dB (0.00022%) at 1 kHz, but the THD+N rises to greater than 7 kHz. Measuring the THD+N vs output amplitude (Figure 57) at 1 kHz shows a constant downward slope until the noise floor of the audio analyzer is reached at 5 V_RMS. The constant downward slope indicates that noise from the device dominates THD+N at this frequency instead of distortion harmonics. Figure 58 and Figure 59 confirm this conclusion. For a 4–dBu signal level, the second harmonic is barely visible above the noise floor at –140 dBu. Increasing the signal level to 20 dBu produces distortion harmonics above the noise floor. The largest harmonic in this case is the second at
–111.2 dBu, or –131.2 dB relative to the fundamental.

Figure 54. Frequency Response

90-kHz Measurement Bandwidth

Figure 56. THD+N vs Frequency

4–dBu Output Amplitude

Figure 58. Output Spectrum

1-VRMS Common-Mode Signal

Figure 55. Common-Mode Rejection Ratio vs Frequency

22-kHz Measurement Bandwidth

Figure 57. THD+N vs Amplitude

20–dBu Output Amplitude

Figure 59. Output Spectrum

8.2.2 Two-Channel Microphone Input for Automotive Infotainment Systems

The high CMRR, low-noise, and ease-of-use in single supply applications make the INA165x-Q1 an excellent choice for applications in automotive infotainment systems. Figure 60 illustrates a high-CMRR input circuit for in-cabin microphones used for hands-free phone systems. The microphones are connected with matched bias resistors, R_BIAS, to preserve the high-CMRR performance of the INA165x-Q1. The exact value of the microphone bias voltage, V_BIAS, and the R_BIAS resistors depends on the particular microphones used. Bandwidth-limiting the audio signal to the range of frequencies for speech is common in hands-free systems. As shown in Figure 60, all filtering components are placed at the output of the INA165x-Q1 rather than the input to preserve high CMRR. The values shown in Figure 60 limit the signal bandwidth to approximately 100 Hz to 10 kHz.

Figure 60. Two-channel Microphone Input for Automotive Infotainment Systems

8.2.3 TRS Audio Interface in Single-Supply Applications

The INA165x-Q1 can be used for auxiliary audio inputs that may use a tip-ring-sleeve (TRS) connector where both audio channels share a common ground connection. Figure 61 shows the INA1650-Q1 configured as a line receiver for a TRS interface to remove common-mode noise on the sleeve connection.

Figure 61. TRS Audio Interface in Single-Supply Applications

9 Power Supply Recommendations

10 Layout

10.1 Layout Guidelines

For best operational performance of the device, use good printed circuit board (PCB) layout practices, including:

• Connect low-ESR, 1-µF and 0.1-µF ceramic bypass capacitors between each supply pin and ground, placed as close as possible to the device. Connecting bypass capacitors only from V+ to ground is acceptable in single-supply applications. Noise can propagate into analog circuitry through the power pins of this device. The bypass capacitors reduce the coupled noise by providing low-impedance pathways to ground.
• Connect the device REF pins to a low-impedance, low-noise, system reference point (such as an analog ground or the VMID(OUT) pin) with the shortest trace possible.
• Place the external components as close to the device as possible, as shown in Figure 62 and Figure 63.
• Use ground pours and planes to shield input signal traces and minimize additional noise introduced into the signal path.
• Keep the length of input traces equal and as short as possible. Route the input traces as a differential pair with as minimal spacing between them as possible.

10.2 Layout Example

Figure 62. Layout Example for a Dual-Supply Line Receiver

Figure 63. Layout Example for a Single-Supply Line Receiver

11 器件和文档支持

11.1 器件支持

11.1.1 开发支持

11.1.1.1 TINA-TI™（免费软件下载）

TINA™是一款简单、功能强大且易于使用的电路仿真程序，此程序基于 SPICE 引擎。TINA-TI 是 TINA 软件的一款免费全功能版本，除了一系列无源和有源模型外，此版本软件还预先载入了一个宏模型库。TINA-TI 提供所有传统的 SPICE 直流、瞬态和频域分析，以及其他设计功能。

TINA-TI 可从 WEBENCH® 设计中心免费下载，它提供全面的后续处理能力，使得用户能够以多种方式形成结果。虚拟仪器提供选择输入波形和探测电路节点、电压和波形的功能，从而创建一个动态的快速入门工具。