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Texas Instruments OPA445BM
- Part No.:
- OPA445BM
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- TO-99-8 Metal Can
- Datasheet:
-
OPA445BM.pdf
- Description:
- IC OPAMP GP 1 CIRCUIT TO99-8
- Quantity:
- Payment:
- Shipping:
Inventory:1,785
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Product details
Overview
OPA445BM from Texas Instruments is a high-voltage, FET-input operational amplifier in TO-99 metal can package, delivering ±15mA output current, 15V/µs slew rate, and ±45V supply capability. It operates across −55°C to +125°C and supports precision signal conditioning in high-common-mode-voltage environments such as piezo drivers and high-voltage regulators.
For engineers reviewing the OPA445BM datasheet, OPA445BM pinout, OPA445BM application, or OPA445BM equivalent, key selection criteria include its ±45V operating range, 10pA input bias current, TO-99 thermal performance (θJA = 200°C/W), offset trim capability, and suitability for capacitive load driving up to 1nF with external compensation.
Technical Context
The OPA445BM uses JFET input stage architecture enabling ultra-low input bias current (±10pA typ) and high input impedance (1013 Ω differential). Its internal laser-trimmed input circuitry achieves ±1mV max input offset voltage over −25°C to +85°C, supporting stable DC-coupled operation in precision high-voltage feedback networks.
It features dual offset trim pins (1 and 5) for manual nulling, a no-connection pin (7), and case-connected V− terminal - critical for thermal and electrical grounding in TO-99 mounting. The device maintains full power bandwidth (70kHz at 70VPP) and low THD+N (0.00008% at 1kHz, 10Vrms) under ±40V supplies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | ±10V to ±45V - enables direct interface with industrial HV rails without external level-shifting or charge pumps. |
| Slew Rate | 15V/µs - supports 70kHz full-power bandwidth at 70VPP, sufficient for fast transient response in piezo actuation and test equipment. |
| Input Bias Current | ±10pA (typ) - permits use of >10MΩ feedback resistors without significant DC error or stability degradation. |
| Output Current | ±15mA - drives moderate loads directly; parallel configuration or external transistors extend capability to 1A per TI application note SBOA015. |
| Input Offset Voltage | ±1mV (max, −25°C to +85°C) - ensures <0.003% gain error in unity-gain buffer configurations at ±35V output swing. |
| Common-Mode Range | (V−)+5V to (V+)-5V - accommodates signals within 5V of either rail, critical for high-side sensing in HV regulator feedback loops. |
| Thermal Resistance | θJA = 200°C/W (TO-99, no heatsink) - requires heatsink above ~0.5W dissipation; junction limited to +150°C max. |
Pinout & Package
OPA445BM is housed in an 8-pin TO-99 metal can package with case connected to V−. This package provides superior thermal conduction versus plastic DIP/SO-8 variants and is suited for high-reliability, high-dissipation applications where mechanical robustness and EMI shielding are required.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Offset Trim (−) | Connects to wiper of 100kΩ potentiometer for input offset nulling; referenced to pin 5. |
| 2 | V+ | Positive supply terminal; bypass with ≥0.1µF capacitor near pin for stability. |
| 3 | −In | Inverting input; high-impedance FET node sensitive to ESD and overvoltage. |
| 4 | +In | Non-inverting input; same impedance and protection requirements as pin 3. |
| 5 | Offset Trim (+) | Reference end of trim potentiometer; tied to pin 1 via adjustable resistor for offset cancellation. |
| 6 | Output | Class-AB output stage capable of ±15mA into resistive loads; drives capacitive loads up to 1nF with RC compensation. |
| 7 | NC | No internal connection; must be left floating or tied to V−, V+, or GND per design needs. |
| 8 | V− | Negative supply terminal; case is internally connected to this pin - requires low-impedance thermal/electrical ground path. |
Key Features
| Feature | Design Value |
|---|---|
| FET input stage | Enables 1014 Ω common-mode input impedance, minimizing loading on high-Z sensors and piezoelectric elements. |
| Laser-trimmed input offset | Reduces initial VOS to ±1mV max and drift to ±10µV/°C, eliminating need for system-level trimming in many HV applications. |
| Offset trim pins (1 & 5) | Allow precise nulling of op amp's own offset only - avoids degrading drift performance by excluding source/system offsets from adjustment. |
| TO-99 metal can package | Provides EMI shielding, mechanical ruggedness, and direct case-to-heatsink thermal path - essential for noise-sensitive test equipment and industrial control. |
| Capacitive load drive support | Stable with up to 1nF load when using RC compensation network (e.g., 20Ω + 0.22µF), per Figure 3 in SBOS156B. |
Applications
| Test Equipment | High-Voltage Regulators |
|---|---|
Use Scenario: Precision DC voltage sourcing and fast transient waveform generation in automated test systems. IC Role / Device Role / Timing Role: Output buffer and gain stage in programmable voltage sources (e.g., Figure 16), delivering 0–50V at 10mA with DAC protection during slewing. Use Value: ±45V supply headroom and 15V/µs slew rate enable accurate reproduction of high-slew test waveforms without clipping or distortion. | Use Scenario: Feedback error amplifier in linear HV regulators supplying ±35V compliance ranges. IC Role / Device Role / Timing Role: High-common-mode-voltage comparator and loop compensator maintaining regulation under wide line/load transients. Use Value: (V−)+5V to (V+)-5V input range allows direct sensing of regulated output while rejecting full-rail common-mode noise. |
| Power Amplifiers | Piezo Drivers |
Use Scenario: Medium-power audio and instrumentation amplification requiring >±30V output swing. IC Role / Device Role / Timing Role: Class-AB output stage driver with ±15mA continuous current, configured as non-inverting amplifier (Figure 1) or current booster (Figure 4). Use Value: Low THD+N (0.00008%) and high open-loop gain (110dB) preserve signal fidelity at high output voltages and frequencies up to 70kHz. | Use Scenario: Bipolar drive for piezoelectric actuators and ultrasonic transducers requiring ±45V excitation. IC Role / Device Role / Timing Role: High-voltage, high-slew buffer in bridge configurations (e.g., Figure 17) doubling effective drive voltage across piezo element. Use Value: 15V/µs slew rate and 1nF capacitive load compatibility ensure fast step response and minimal settling time in position-control loops. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage operational amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA445AP | DIP-8 plastic package; θJA = 100°C/W; no metal case; same electrical specs. | Lacks EMI shielding and direct heatsinking; less suitable for noisy industrial environments or high-dissipation layouts. | Select OPA445AP only when board space, cost, or through-hole assembly constraints outweigh thermal/EMI requirements. |
| OPA445ADDA | SO-8 PowerPAD package; θJA = 52°C/W (with heat-spreader); pin-compatible with SO-8; same electrical specs. | Surface-mount optimized for thermal performance on PCB; requires specific layout (vias, copper area) but eliminates external heatsink. | Choose OPA445ADDA for compact, high-power-density designs needing >1W continuous dissipation without TO-99 footprint or mounting hardware. |
Compared with OPA445AP and OPA445ADDA, the OPA445BM offers superior EMI immunity and mechanical robustness via its TO-99 metal can, while trading off PCB area and thermal resistance - making it optimal for benchtop test gear, military-grade regulators, and piezo systems where reliability and noise rejection are prioritized over miniaturization.
Availability
OPA445BM is available at Aetrix Electronics and suitable for test equipment, high-voltage regulators, and piezo drivers requiring stable component supply, long-term obsolescence management, and traceable sourcing from authorized channels.
Supply support for OPA445BM includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and high-reliability components for industrial, automotive, and aerospace applications.
The OPA445BM belongs to TI's high-voltage precision op amp product line, engineered for applications demanding wide supply range, low input bias, and robust thermal performance in harsh environments.
FAQ
What is the maximum safe operating voltage for the OPA445BM?
The OPA445BM has an absolute maximum power supply rating of ±50V, but its specified operating range is ±10V to ±45V. Operation at ±45V is fully characterized across temperature and load conditions per SBOS156B. Exceeding ±45V risks violating parametric limits and may reduce long-term reliability even if within absolute max ratings.
Does the OPA445BM require external input protection diodes?
Yes - the OPA445BM's FET inputs lack internal protection diodes. If input voltage may exceed the supply rails (e.g., during power sequencing or fault conditions), a series current-limiting resistor (e.g., 10kΩ) is required to prevent destructive gate-source conduction. TI Application Note SBOA015 details protection strategies compatible with OPA445BM.
Can the OPA445BM drive a 1000pF capacitive load stably?
Yes, but only with external compensation. As shown in Figure 3 of SBOS156B, a 20Ω resistor in series with a 0.22µF capacitor between output and inverting input stabilizes the OPA445BM for 1000pF loads. Without this network, phase margin erosion causes overshoot or oscillation - confirmed by typical overshoot vs. load capacitance curves.
What is the purpose of Pin 7 (NC) on the OPA445BM?
Pin 7 is a no-connection terminal with no internal bond wire. TI documentation explicitly states it may be left floating or connected to V−, V+, or GND based on mechanical or grounding needs - for example, tying it to V− improves thermal conduction in TO-99 mounting. It must never be used as a signal path or current return.
How does the OPA445BM's TO-99 package affect thermal design?
The OPA445BM's TO-99 package has θJA = 200°C/W (no heatsink), meaning 0.5W dissipation raises junction temperature by 100°C above ambient. To stay within the +150°C max junction limit, active heatsinking (e.g., Thermalloy 2257 clip-on) reducing θJA by ~50°C/W is recommended for continuous >0.3W operation - verified in Figure 7 of SBOS156B.
OPA445BM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-99-8 Metal Can
- Packaging:
- Tube
- Product Status:
- Active
- Amplifier Type:
- General Purpose
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 15V/µs
- Gain Bandwidth Product:
- 2 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 10 pA
- Voltage - Input Offset:
- 1 mV
- Current - Supply:
- 4.2mA
- Current - Output / Channel:
- 15 mA
- Voltage - Supply Span (Min):
- 20 V
- Voltage - Supply Span (Max):
- 90 V
- Operating Temperature:
- -25°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-99-8
OPA445BM FAQ
1.How can I place an order for OPA445BM through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA445BM on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for OPA445BM reliable?
The price and inventory of OPA445BM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA445BM is usually 5 days.
3.What payment methods are accepted for OPA445BM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA445BM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA445BM?
OPA445BM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA445BM order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for OPA445BM?
For technical support, including OPA445BM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA445BM requirements.
6.How does Aetrix verify that OPA445BM is sourced from the original manufacturer or authorized distributors?
All OPA445BM products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that OPA445BM meets industry standards.
7.What is the process for return or replacement of OPA445BM?
All OPA445BM units undergo pre-shipment inspection (PSI). If there is an issue with OPA445BM, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The OPA445BM part is unused and in its original packaging.
Return procedure for OPA445BM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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