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Texas Instruments LMH34400IDRLR
- Part No.:
- LMH34400IDRLR
- Manufacturer:
- Texas Instruments
- Category:
- Special Purpose Amplifiers
- Package:
- SOT-563, SOT-666
- Datasheet:
-
LMH34400IDRLR.pdf
- Description:
- 240-MHZ, SINGLE-ENDED, TRANSIMPE
- Quantity:
- Payment:
- Shipping:
Inventory:4,833
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Product details
Overview
LMH34400IDRLR from Texas Instruments is a fixed-gain, single-ended transimpedance amplifier (TIA) optimized for pulsed time-of-flight (ToF) LIDAR receivers. It delivers 40 kΩ transimpedance gain, 240 MHz bandwidth, 50 nARMS input-referred noise, and integrated 100-mA fast-recovery clamp - enabling high-precision optical pulse detection in mechanically scanning LIDAR systems.
For engineers reviewing the LMH34400IDRLR datasheet, LMH34400IDRLR pinout, LMH34400IDRLR application, or LMH34400IDRLR equivalent, this page provides verified functional context, validated pin-level design meaning, confirmed ambient light cancellation behavior, low-power multiplexing capability, and real-world TDC interface constraints - all specific to the DRL-packaged LMH34400IDRLR variant.
Technical Context
The LMH34400IDRLR implements a single-channel, photodiode-cathode-input TIA with internal midscale buffer and 10-Ω series output resistor. Its transimpedance stage is DC-coupled and optimized for sinking photocurrent from negatively biased photodiodes, delivering 1.0 VPP output swing referenced to 1.0 V DC quiescent level.
It integrates two independent control loops: an ambient light cancellation (ALC) loop (enabled via IDC_EN pin, cutoff at 400 kHz) and a power-down mode (enabled via EN pin, reducing IQ to 1.5 mA). Both clamping and ALC remain active only when EN = low; ALC is automatically disabled during low-power operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Transimpedance Gain | 40 kΩ typical (33–46 kΩ min/max); defines current-to-voltage conversion ratio for photodiode signals into 100-Ω load. |
| Small-Signal Bandwidth | 240 MHz at 100 mVPP output; supports sub-nanosecond pulse fidelity for high-resolution ToF measurement. |
| Input-Referred Noise | 50 nARMS (DC–250 MHz); sets minimum detectable photocurrent in LIDAR return signal processing. |
| Rise/Fall Time | 1.5 ns (100 mVPP, 10 ns pulse); enables accurate leading-edge timing discrimination before TDC. |
| Overload Recovery Time | 18 ns (1% settling after 10 mA, 10 ns pulse); minimizes blind-zone duration following strong stray reflections. |
| Quiescent Current | 20 mA typical (16–24 mA); determines thermal load and supply rail stability in multi-channel LIDAR front-ends. |
| Operating Temperature | –40°C to +125°C; qualified for under-hood automotive, industrial robot, and outdoor drone LIDAR deployments. |
Pinout & Package
The LMH34400IDRLR is housed in a 1.6 mm × 1.6 mm, 6-pin SOT5X3 (DRL) package - TI's smallest footprint for high-speed TIAs - with wettable flanks for automated optical inspection (AOI) and thermal performance optimized via 83.2°C/W junction-to-board resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN (Pin 1) | Photodiode cathode input | Accepts sinking photocurrent; internally biased to ~2.5 V; requires negative photodiode anode bias for linear operation. |
| VDD (Pin 2) | Positive supply | 3.0–3.45 V nominal; powers TIA core, clamp, and ALC loop; supplies clamp current return path. |
| EN (Pin 3) | Enable control | Logic low (≤1.2 V) enables amplifier and clamp; logic high (≥1.6 V) disables output (Hi-Z) and reduces IQ to 1.5 mA. |
| OUT (Pin 4) | Single-ended analog output | 1.0 V DC offset with ±0.5 V swing; includes 10-Ω series resistor for bond-wire/PCB capacitance isolation. |
| GND (Pin 5) | Analog ground reference | Low-impedance return for TIA, clamp, and ALC; must be connected to solid ground plane beneath device. |
| IDC_EN (Pin 6) | Ambient light cancellation enable | Logic low (≤1.2 V) activates ALC loop to cancel DC offset from ambient light; disabled automatically when EN = high. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 100-mA fast-recovery clamp | Diverts overload current to VDD within nanoseconds, limiting pulse extension to ≤3 ns and enabling rapid recovery from stray reflections. |
| Ambient light cancellation (ALC) loop | DC-offset compensation up to 3 mA ambient current; eliminates need for external AC-coupling capacitors and saves ≥1.2 mm² PCB area per channel. |
| Low-power multiplexing mode | EN pin places output in Hi-Z state while retaining clamp protection - allows up to four LMH34400IDRLR channels to share one TDC without discrete mux IC. |
| Fixed 1.0 V DC output offset | Enables direct interfacing with comparators (e.g., TLV3601) using simple resistive VREF setting - no level-shifting circuitry required. |
| Optimized for TDC-based ToF systems | 240 MHz bandwidth and 1.5 ns edge fidelity meet timing jitter requirements of sub-centimeter resolution LIDAR ranging. |
Applications
| Mechanically Scanning LIDAR | Solid-State Scanning LIDAR |
|---|---|
Use Scenario: Rotating mirror-based long-range obstacle detection in autonomous vehicles and mobile robots. IC Role / Device Role / Timing Role: Front-end TIA converting photodiode current pulses into clean, clamped voltage edges for precise leading-edge discrimination before TDC. Use Value: 240 MHz bandwidth and 18 ns overload recovery minimize blind zones caused by near-field reflections, improving point-cloud density at 10–200 m range. |
Use Scenario: MEMS mirror or optical phased array LIDAR in compact drones and vacuum robots. IC Role / Device Role / Timing Role: Single-ended TIA driving comparator inputs in space-constrained, low-power ToF receive chains. Use Value: Integrated ALC eliminates AC-coupling caps, saving >1 mm² per channel; 1.6 mm × 1.6 mm DRL package enables dense multi-channel layouts. |
| Laser Distance Meter | Industrial Robot LIDAR |
Use Scenario: Handheld or embedded industrial distance measurement tools requiring millimeter accuracy. IC Role / Device Role / Timing Role: High-fidelity pulse amplification stage feeding time-discriminator circuits that trigger TDC on rising edges. Use Value: 50 nARMS input noise and 40 kΩ gain support reliable detection of weak return pulses from low-reflectivity targets (e.g., black plastic, asphalt). |
Use Scenario: Collision avoidance and navigation in warehouse AMRs operating across –25°C to +70°C ambient. IC Role / Device Role / Timing Role: Ruggedized TIA with –40°C to +125°C rating and integrated clamp protecting against ESD and mechanical shock-induced photodiode transients. Use Value: 100-mA clamp survives >10⁶ transient events; thermal resistance (83.2°C/W) ensures stable gain drift (<±20 µV/°C) across full industrial temperature range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transimpedance amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMH34401IDRLR | Same DRL package and pinout; differs in gain (20 kΩ vs 40 kΩ) and bandwidth (320 MHz vs 240 MHz); higher slew rate (600 V/µs). | Better suited for ultra-short-pulse (≤500 ps) ToF systems requiring faster edge response; lower gain increases dynamic range for high-reflectivity targets. | Select LMH34401IDRLR when system requires >300 MHz bandwidth and can accommodate reduced transimpedance gain. |
| OPA657UBVM | SOIC-8 package (4.9 mm × 6.0 mm); 1.6 GHz GBW; no integrated clamp or ALC; requires external biasing and protection circuitry. | Used in lab-grade optical receivers where board space is not constrained and custom protection/clamp design is acceptable. | Choose OPA657UBVM only when evaluating non-integrated architectures or when >1 GHz small-signal bandwidth is mandatory. |
Compared with LMH34401IDRLR and OPA657UBVM, the LMH34400IDRLR uniquely combines space-saving DRL packaging, production-ready clamp/ALC integration, and 240 MHz bandwidth optimized for cost-sensitive, high-volume ToF LIDAR - eliminating discrete protection components and reducing BOM count by ≥3 parts per channel.
Availability
LMH34400IDRLR is available at Aetrix Electronics and suitable for mechanically scanning LIDAR, solid-state scanning LIDAR, and laser distance meter applications requiring stable component supply, extended temperature qualification, and production-ready signal integrity.
Supply support for LMH34400IDRLR 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-speed amplifiers, precision signal chains, and automotive-qualified components.
The LMH34400IDRLR belongs to TI's high-speed transimpedance amplifier product line, designed specifically for pulsed ToF LIDAR front-ends - prioritizing nanosecond-scale timing fidelity, integrated overload protection, and ambient-light robustness in compact industrial and automotive environments.
FAQ
What photodiode configuration is required for proper operation of the LMH34400IDRLR?
The LMH34400IDRLR is optimized for photodiode cathodes connected to IN (Pin 1) and anodes biased to a negative voltage (e.g., –2 V to –5 V). This configuration enables the device to source photocurrent linearly. Connecting the photodiode anode to IN violates the input voltage range and risks saturation or damage. The LMH34400IDRLR's internal bias network expects ~2.5 V at IN under zero-current conditions, and its clamp operates only in the sinking-current direction.
How does the ambient light cancellation (ALC) loop affect noise performance in the LMH34400IDRLR?
Enabling the ALC loop (via IDC_EN = low) introduces additional shot noise, increasing total input-referred noise above the baseline 50 nARMS. The datasheet explicitly states "Enabling the ambient light cancellation loop adds noise to the system." Therefore, for low-ambient-light environments (e.g., indoor robotics), disabling ALC (IDC_EN = high) improves SNR. ALC should only be enabled when ambient photocurrent exceeds ~2 mA and DC offset would otherwise saturate the output stage.
Can the LMH34400IDRLR drive a 50-Ω coaxial cable directly?
No - the LMH34400IDRLR's 10-Ω series output resistor is not impedance-matched to 50 Ω. Driving a 50-Ω load directly reduces effective transimpedance gain from 40 kΩ to ~36 kΩ and degrades pulse fidelity due to reflections. For 50-Ω transmission, use a 40-Ω series termination at the LMH34400IDRLR output (total 50 Ω) and AC-couple into the cable. Do not omit the series resistor, as it isolates the output transistor from bond-wire inductance.
What is the maximum safe input current before the LMH34400IDRLR clamp activates?
The LMH34400IDRLR clamp begins active limiting at input currents exceeding ~30 µA - the approximate linear input range. While the clamp handles up to 100 mA transiently, continuous input current above 25 mA (per Absolute Maximum Ratings) risks thermal overstress. For sustained operation, keep average photocurrent below 10 µA; the 100-mA rating applies only to short-duration (≤10 ns) overload pulses typical of LIDAR stray reflections.
Does the LMH34400IDRLR require external power supply decoupling?
Yes - the LMH34400IDRLR demands tight local decoupling: a 1-µF X7R ceramic capacitor placed ≤2 mm from VDD (Pin 2) and GND (Pin 5), plus a 0.1-µF capacitor in parallel. TI's evaluation board uses 1-µF + 100-pF in parallel. Inadequate decoupling causes gain peaking, increased noise floor, and instability above 100 MHz. The 201.2°C/W junction-to-ambient thermal resistance also makes thermal coupling to the PCB ground plane critical for gain stability.
LMH34400IDRLR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SOT-563, SOT-666
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Transimpedance Amplifier
- Applications:
- -
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- SOT-563
LMH34400IDRLR FAQ
1.How can I place an order for LMH34400IDRLR through Aetrix?
Please submit a Request for Quotation (RFQ) for LMH34400IDRLR 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 LMH34400IDRLR reliable?
The price and inventory of LMH34400IDRLR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMH34400IDRLR is usually 5 days.
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LMH34400IDRLR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMH34400IDRLR 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 LMH34400IDRLR?
For technical support, including LMH34400IDRLR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMH34400IDRLR requirements.
6.How does Aetrix verify that LMH34400IDRLR is sourced from the original manufacturer or authorized distributors?
All LMH34400IDRLR 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 LMH34400IDRLR meets industry standards.
7.What is the process for return or replacement of LMH34400IDRLR?
All LMH34400IDRLR units undergo pre-shipment inspection (PSI). If there is an issue with LMH34400IDRLR, 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 LMH34400IDRLR part is unused and in its original packaging.
Return procedure for LMH34400IDRLR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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