My Inquiry
My Account
Texas Instruments OPA857TD2
- Part No.:
- OPA857TD2
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- Die
- Datasheet:
-
OPA857TD2.pdf
- Description:
- IC OPAMP GP 1 CIRCUIT DIE
- Quantity:
- Payment:
- Shipping:
Inventory:1,449
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
OPA857TD2 from Texas Instruments is an ultralow-noise, wideband transimpedance amplifier (TIA) in bare-die format, designed for photodiode monitoring with selectable 5-kΩ or 20-kΩ internal feedback resistance, 125 MHz closed-loop bandwidth (at 5-kΩ), 15 nARMS input-referred current noise, and 23.4 mA supply current at 2.7–3.6 V.
For engineers reviewing the OPA857TD2 datasheet, OPA857TD2 pinout, OPA857TD2 application, or OPA857TD2 equivalent, key selection considerations include its die-level packaging for hybrid optical module integration, fast <25 ns overload recovery, pseudo-differential output architecture, and dual-gain configurability via CTRL pin logic level.
Technical Context
The OPA857TD2 implements a high-speed, low-noise transimpedance front-end with internal gain-select logic: CTRL pin grounded selects 5-kΩ transimpedance (125 MHz BW, 1.5-pF parasitic), while pulled to +VS selects 20-kΩ (105 MHz BW, same parasitic). Its input stage includes integrated protection diodes and operates across –40°C to +85°C.
It delivers pseudo-differential outputs (OUT and OUTN) referenced to midscale voltage, enabling DC-coupled interfacing with ADCs or downstream signal chains without external level-shifting. The die's bond pad metallization is TiW/AlCu (0.5%), with 1100 nm thickness and GND backside potential.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Transimpedance Gain | Selectable: 5 kΩ (125 MHz BW) or 20 kΩ (105 MHz BW) - enables dynamic range optimization per optical signal level |
| Input Noise | 15 nARMS (brickwall BW = 135 MHz, 20-kΩ mode) - supports detection of weak photocurrents in high-bandwidth systems |
| Overload Recovery | <25 ns - minimizes dead time after photodiode saturation, critical for pulsed optical sensing |
| Supply Voltage | 2.7 V to 3.6 V - compatible with single-supply 3.3-V optical subsystems |
| Supply Current | 23.4 mA - defines power budget for compact, thermally constrained optical modules |
| Operating Temp | –40°C to +85°C - qualified for industrial and medical imaging environments |
| Input Protection | Integrated diodes - eliminates need for external clamping in photodiode front-ends |
Pinout & Package
Bare die in gel pak VR format; 15-mil thickness; silicon backside with GND potential; TiW/AlCu (0.5%) bond pads, 1100 nm thick.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pads 1,3,4,6,7,12) | Ground reference | Multiple dedicated ground pads ensure low-inductance return paths for RF-sensitive TIA operation |
| CTRL (Pad 2) | Gain select control | Logic-low (GND) → 5-kΩ gain; logic-high (+VS) → 20-kΩ gain - enables real-time gain switching in system firmware |
| OUT (Pad 8) | Differential signal output | Active output node delivering inverted signal relative to OUTN; drives 50-Ω or high-Z loads |
| OUTN (Pad 5) | Common-mode reference output | Provides midscale DC reference (VCM) for pseudo-differential signaling and ADC biasing |
| IN (Pad 15) | Photocurrent input | High-impedance, protected input optimized for low-capacitance photodiode connection |
| +VS (Pads 9,10,11) | Positive supply | Three distributed supply pads reduce IR drop and improve PSRR at RF frequencies |
| TESD_SD (Pad 13) | Test mode enable | Connect to GND for normal operation; +VS activates internal test circuitry - not used in production optical modules |
| TEST_IN (Pad 14) | Test input | Must be tied to +VS during normal operation; unused in application circuits |
Key Features
| Feature | Design Value |
|---|---|
| Selectable transimpedance gain | Hardware-configurable 5-kΩ / 20-kΩ modes via single CTRL pin - eliminates external resistor networks and layout rework |
| Pseudo-differential output architecture | OUT + OUTN pair provides inherent common-mode rejection and simplifies AC-coupling or DC-biased ADC interface design |
| Ultralow input-referred current noise | 15 nARMS in 20-kΩ mode - enables sub-picoamp photocurrent resolution in high-speed LIDAR or PET scanner front-ends |
| Fast overload recovery | <25 ns recovery from saturation - preserves timing fidelity in burst-mode optical receivers |
| Integrated input protection | On-die ESD diodes eliminate need for external TVS or series resistors - reduces BOM count and board area in space-constrained modules |
Applications
| Photodiode Monitoring | Optical Amplifier Front-End |
|---|---|
Use Scenario: Real-time laser power stabilization using feedback from a monitor photodiode in fiber-optic transceivers. IC Role / Device Role / Timing Role: Transimpedance amplifier converting photodiode current to voltage with minimal added noise and delay. Use Value: 125 MHz bandwidth at 5-kΩ gain enables accurate tracking of fast power fluctuations; <25 ns overload recovery prevents control loop disruption during transient laser spikes. | Use Scenario: Input stage of an Erbium-Doped Fiber Amplifier (EDFA) monitoring circuit detecting pump laser degradation. IC Role / Device Role / Timing Role: High-dynamic-range TIA capturing both low-level aging signals and high-power fault conditions. Use Value: Dual-gain configuration allows automatic switching between 20-kΩ (high sensitivity) and 5-kΩ (high headroom) modes - extending operational life without hardware change. |
| CAT-Scanner Detector | High-Speed I/V Conversion |
Use Scenario: Signal conditioning for scintillation detector arrays in computed tomography systems requiring precise photon counting. IC Role / Device Role / Timing Role: Low-noise, fast-settling TIA interfacing with avalanche photodiodes (APDs) in multi-channel acquisition ASICs. Use Value: 15 nARMS input noise ensures high signal-to-noise ratio for low-dose imaging; –40°C to +85°C rating supports thermal stability in gantry-mounted electronics. | Use Scenario: Converting fast-rising current pulses from particle detectors or time-of-flight sensors into measurable voltage waveforms. IC Role / Device Role / Timing Role: Wideband current-to-voltage converter preserving pulse shape integrity up to 105 MHz. Use Value: 105 MHz bandwidth at 20-kΩ gain maintains sub-nanosecond edge fidelity; pseudo-differential outputs suppress ground bounce in dense PCB layouts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transimpedance amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA855IDSGR | Single-ended output; fixed 5-kΩ gain; 1.8-V to 5.4-V supply; 16-pin WQFN package | Designed for PCB-mount evaluation and lower-frequency (<80 MHz) optical sensing | Choose when board space permits packaged ICs and pseudo-differential output is not required |
| LMH6629MA/NOPB | No internal feedback resistor; requires external RF; higher 3.3-nV/√Hz voltage noise; 1.2-GHz GBW | Used in ultra-wideband (>500 MHz) custom TIAs where gain and bandwidth are set externally | Choose when full flexibility in transimpedance value and compensation is needed, and noise floor is secondary to bandwidth |
Compared with OPA857TD2, OPA855IDSGR offers ease of prototyping but lacks die-level integration and dual-gain flexibility, while LMH6629MA/NOPB provides higher raw bandwidth at the cost of increased design complexity and higher input noise - making OPA857TD2 optimal for production optical modules demanding low-noise, configurable gain, and compact form factor.
Availability
OPA857TD2 is available at Aetrix Electronics and suitable for photodiode monitoring, CAT-scanner front-ends, and optical amplifier applications requiring stable component supply, controlled die-level sourcing, and long-term industrial temperature support.
Supply support for OPA857TD2 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 company specializing in analog and embedded processing technologies, with leadership in high-performance signal chain and power management solutions.
The OPA857-DIE product line targets optical sensing systems requiring ultralow-noise, high-bandwidth transimpedance amplification in space-constrained, thermally demanding environments such as medical imaging and telecom modules.
FAQ
What is the function of the CTRL pin on the OPA857TD2?
The CTRL pin on the OPA857TD2 selects transimpedance gain: grounding it configures the internal feedback resistance to 5 kΩ (125 MHz bandwidth), while connecting it to +VS selects 20 kΩ (105 MHz bandwidth). This hardware-based selection enables deterministic gain switching without digital control overhead. The OPA857TD2 uses this pin to simplify optical front-end design across varying signal levels without external components.
Does the OPA857TD2 require external feedback resistors?
No, the OPA857TD2 integrates selectable 5-kΩ and 20-kΩ feedback resistors internally - eliminating the need for external resistors and associated parasitics that degrade bandwidth and noise performance. This integration is confirmed in the SBOS813 datasheet, which specifies closed-loop bandwidths and noise values based solely on internal resistance selection. The OPA857TD2 thus reduces layout sensitivity and improves repeatability in high-volume optical module assembly.
What is the significance of the OUTN pin on the OPA857TD2?
The OUTN pin on the OPA857TD2 provides a stable midscale reference voltage (VCM) that establishes the common-mode level for the pseudo-differential output pair (OUT/OUTN). It enables direct interfacing with differential-input ADCs or instrumentation amplifiers without external level-shifting circuitry. In the OPA857TD2, this feature reduces component count and preserves signal integrity in high-speed optical receiver designs.
How is the OPA857TD2 packaged, and what does "TD" signify?
The OPA857TD2 is supplied as bare die in gel pak VR format, with "TD" denoting Texas Instruments' die-level packaging designation. It has no leadframe or molded body - only silicon die with aluminum bond pads, intended for flip-chip or wire-bond integration into hybrid optical subassemblies. The OPA857TD2's 15-mil thickness and TiW/AlCu metallization are specified for reliable interconnect in hermetic or epoxy-encapsulated modules.
What is the maximum allowable parasitic capacitance at the IN pin for stable OPA857TD2 operation?
The OPA857TD2's specified bandwidths assume 1.5 pF of total external parasitic capacitance at the IN pin, including photodiode junction capacitance and trace capacitance. Exceeding this value degrades bandwidth and may cause peaking or instability - for example, at 20-kΩ gain, bandwidth drops below 105 MHz if capacitance exceeds 1.5 pF. System designers must minimize layout capacitance and select photodiodes with ≤1.0 pF junction capacitance to maintain performance margins in the OPA857TD2.
OPA857TD2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- Die
- Packaging:
- Tray
- Product Status:
- Active
- Amplifier Type:
- Transimpedance
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 220V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 130 MHz
- Current - Input Bias:
- 1 µA
- Voltage - Input Offset:
- -
- Current - Supply:
- 23.4mA
- Current - Output / Channel:
- 50 mA
- Voltage - Supply Span (Min):
- 2.6 V
- Voltage - Supply Span (Max):
- 3.6 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- Die
OPA857TD2 FAQ
1.How can I place an order for OPA857TD2 through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA857TD2 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 OPA857TD2 reliable?
The price and inventory of OPA857TD2 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA857TD2 is usually 5 days.
3.What payment methods are accepted for OPA857TD2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA857TD2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA857TD2?
OPA857TD2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA857TD2 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 OPA857TD2?
For technical support, including OPA857TD2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA857TD2 requirements.
6.How does Aetrix verify that OPA857TD2 is sourced from the original manufacturer or authorized distributors?
All OPA857TD2 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 OPA857TD2 meets industry standards.
7.What is the process for return or replacement of OPA857TD2?
All OPA857TD2 units undergo pre-shipment inspection (PSI). If there is an issue with OPA857TD2, 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 OPA857TD2 part is unused and in its original packaging.
Return procedure for OPA857TD2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
OPA857TD2 Tags
-
LM358DT
STMicroelectronics
-
LM358DR
Texas Instruments
-
LM2904DR
Texas Instruments
-
LM358ADR
Texas Instruments
-
LM2904DGKR
Texas Instruments
-
LM324DR
Texas Instruments
-
MCP6006T-E/OT
Microchip Technology
-
MCP6006UT-E/OT
Microchip Technology
-
LM324PWR
Texas Instruments
-
LM2902PWR
Texas Instruments
-
LM2902DR
Texas Instruments
-
LM358P
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
