L9825TR

STMicroelectronics L9825TR octal low‑side driver: protected, compact, and ready for automotive loads

Overview
The STMicroelectronics L9825TR is an octal low-side automotive driver designed to simplify high-side system control by switching loads to ground. With eight protected outputs, integrated current limiting, and thermal shutdown, it targets relay, lamp, solenoid, and other inductive or resistive loads commonly found in vehicles and industrial equipment. Packaged in a compact PowerSO-20 and supplied in Tape & Reel (TR), the L9825TR is optimized for automated assembly and high-volume builds.

Engineers evaluating multi-channel load control will appreciate the L9825TR’s blend of protection features and channel density, while sourcing teams get a clear part number, package, and packaging format that streamlines procurement.

Key value at a glance

• Eight low-side switches for high channel density on a small footprint
• Integrated protection: current limiting (typ. 1.75 A) and thermal shutdown
• Automotive- and industrial-oriented use across relays, lamps, and solenoids
• PowerSO-20 package, Tape & Reel (TR) for automated SMT lines

Specifications

• Manufacturer / Brand: STMicroelectronics
• MPN: L9825TR
• Device type: Octal low-side driver (8 channels)
• Current limiting (typical): 1.75 A
• Package: PowerSO-20
• Packaging: Tape & Reel (TR)
• Mounting: Surface Mount
• Pin count: 20

Parameters not specified in datasheet
To avoid misapplication and ensure correct derating, confirm the following in the official datasheet before final design decisions. Where not present in the provided data set, they are noted as “Not specified in datasheet.”

• Supply voltage range: Not specified in datasheet
• Output clamp/flyback strategy: Not specified in datasheet
• Output on-resistance (per channel) and thermal characteristics: Not specified in datasheet
• Input/logic interface thresholds and compatible logic families: Not specified in datasheet
• Diagnostic reporting (open-load, short-circuit flags, fault pins): Not specified in datasheet
• PWM frequency capability and switching dynamics: Not specified in datasheet
• Operating temperature range and storage temperature: Not specified in datasheet
• Automotive qualification level: Not specified in datasheet
• Environmental/RoHS status: Not specified in datasheet

How the L9825TR fits into your design
For multi-load control, distributing eight low-side drivers in one IC reduces board area, interconnect complexity, and design variability compared to discrete transistors plus protection components. The L9825TR integrates the most critical protections—current limiting and thermal shutdown—helping prevent damage from overloads, wiring faults, or prolonged high-current events. This integration can shorten validation time and reduce the number of line items in your BOM.

As a low-side device, the L9825TR sits between the load and ground, allowing the load’s positive side to remain tied to the supply through a fuse or high-side source. This topology is well suited to loads like lamps and solenoids where ground switching is standard, and it pairs cleanly with high-side power distribution modules if required.

Applications

• Automotive load driving (lamps, relays, solenoids)
• Industrial load control
• General-purpose low-side switching

Example system contexts

• Body electronics: indicator lamps, interior lighting segments, small relays
• Powertrain and chassis subsystems: control valves and solenoid actuators (verify electrical limits per datasheet)
• Industrial machines: relay banks, pilot lamps, and low-voltage solenoid manifolds

Protection and reliability highlights

• Current limiting (typ. 1.75 A) helps protect against overcurrent conditions and wiring faults
• Thermal shutdown provides an additional layer of self-protection during abnormal thermal events
• Eight independent channels enable graceful degradation—faults can be isolated to a single output without taking down the entire load bank (system design dependent)

Note: For fault timing, auto-retry behavior, latch-off mechanisms, or diagnostics, consult the official datasheet. Where such details are not in the provided data, they are Not specified in datasheet.

Packaging, handling, and assembly

• Package: PowerSO-20 provides a compact footprint with thermal paths appropriate to surface-mount assembly. Board copper, vias, and airflow significantly influence thermal performance; consult the package application notes and the thermal section of the datasheet for layout guidance.
• Packaging format: Tape & Reel (TR) facilitates automated pick-and-place on SMT lines and is ideal for high-volume production.

Assembly best practices

• Use the recommended land pattern for PowerSO-20 and observe solder paste aperture guidance to balance wetting and voiding.
• Provide robust ground copper beneath the device (as layout rules allow) to improve thermal spreading for low-side switching.
• Keep high di/dt load return paths short and routed to the same ground reference as the device to minimize ground bounce.

Design-in considerations

• Channel allocation: Map higher-stress loads (e.g., larger solenoids) to channels with the most favorable copper/thermal paths on your PCB. Even channel utilization improves thermal distribution.
• Inductive load management: When switching inductive loads, pay close attention to energy dissipation and clamp strategy. If integrated clamping or recirculation specifics are required, they are Not specified in datasheet in the provided set—verify the official document and add external suppression components as recommended.
• Control interface: Whether the inputs are active-high, TTL/CMOS compatible, or include internal pull-ups/pull-downs is Not specified in datasheet; confirm thresholds and input current before final logic-level decisions.
• PWM and dimming: For lamp dimming or solenoid current control via PWM, allowable frequency range and switching losses are Not specified in datasheet here; validate experimentally within the device’s safe operating area per the datasheet.
• Thermal budgeting: Current limiting (typ. 1.75 A) is a protection feature, not a design target for continuous operation without thermal analysis. Model worst-case ambient conditions and duty cycles, then confirm junction temperature margins.

Why choose STMicroelectronics L9825TR for sourcing

• Channel consolidation: Eight outputs reduce IC count and simplify procurement for multi-load designs.
• Protection integrated: Built-in current limiting and thermal shutdown reduce reliance on external protection components, lowering BOM risk and assembly complexity.
• Manufacturing-ready: PowerSO-20 in Tape & Reel supports standard SMT flows and high-throughput placement.
• Clear ordering: The specific ordering code L9825TR helps avoid ambiguity in package and packaging during quoting and purchasing.

Lifecycle and replacements

• Lifecycle status: Not specified in datasheet
• Drop-in or functional replacements: Not specified in datasheet
  If your project requires second sources, consider defining system-level requirements (channel count, current capability, package, diagnostics) and perform a parametric search across STMicroelectronics’ portfolio and comparable low-side drivers from other vendors. Always verify pin compatibility and thermal behavior; “form-fit-function” equivalence is rare without schematic and layout changes.

Compliance and environmental

• RoHS/REACH or other environmental compliance: Not specified in datasheet
• Automotive qualification level: Not specified in datasheet
  Procurement teams should request current compliance statements and material declarations from authorized STMicroelectronics channels, and confirm any required automotive qualification.

Frequently asked questions (FAQs)
Q: What is the STMicroelectronics L9825TR?
A: It is an octal low-side driver IC with eight protected outputs, designed for automotive and industrial loads such as relays, lamps, and solenoids.

Q: How many channels does the L9825TR provide?
A: Eight low-side switching channels.

Q: What protection features are integrated?
A: Current limiting (typ. 1.75 A) and thermal shutdown.

Q: What package and packaging does the L9825TR use?
A: PowerSO-20 package, supplied in Tape & Reel (TR).

Q: Is the L9825TR suitable for PWM dimming or current control?
A: PWM capability and recommended frequency range are Not specified in datasheet in the provided data. Verify in the official datasheet and qualify through testing under your operating conditions.

Q: What is the supply voltage range and logic input level compatibility?
A: Not specified in datasheet in the provided data set. Consult the official documentation to confirm logic thresholds and supply limits.

Q: Does the device include integrated flyback or clamp diodes for inductive loads?
A: Not specified in datasheet in the provided data. For inductive load protection, follow the recommendations in the official datasheet or add external suppression as needed.

Q: Is the L9825TR automotive-qualified?
A: Automotive qualification level is Not specified in datasheet in the provided data. Confirm with STMicroelectronics or authorized distributors if your program requires a specific qualification.

Q: What is the typical current limit per channel?
A: 1.75 A (typical), per the provided data.

Sourcing checklist

• MPN and brand: STMicroelectronics L9825TR
• Package and format: PowerSO-20, Tape & Reel (TR)
• Channel count and type: 8 channels, low-side
• Protections: Current limiting (typ. 1.75 A), thermal shutdown
• Compliance and lifecycle: Request latest statements (Not specified in datasheet here)
• Manufacturing: Confirm PowerSO-20 land pattern and SMT process window

Resources

• Datasheet: https://www.st.com/resource/en/datasheet/l9825.pdf

Final thoughts
The STMicroelectronics L9825TR brings eight protected low-side switches together in a compact PowerSO-20 package, aligning well with automotive and industrial needs for relay, lamp, and solenoid control. By combining current limiting and thermal shutdown with high channel density, it can simplify your load-driving architecture, reduce external protection components, and streamline sourcing with a clear, SMT-friendly ordering code. For all electrical limits, timing, diagnostics, and compliance details not covered in the provided data, refer to the official STMicroelectronics datasheet and validate performance in your end application.