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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Power Management - Specialized

STMicroelectronics L9686

Name: L9686
Brand: STMicroelectronics
SKU: L9686
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L9686

Manufacturer:: STMicroelectronics

Category:: Power Management - Specialized

Package:: 8-DIP (0.300", 7.62mm)

Datasheet:: L9686.pdf

Description:: IC DIRECTION INDICATOR 8-MINIDIP

Quantity:: RFQ Add To RFQ list

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Inventory:2,951

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Product details

Overview

L9686 from STMicroelectronics is an automotive direction indicator relay driver IC designed to control turn signal flashers in vehicles. It provides dual-frequency oscillation (1.27–1.74 Hz normal / 0.53–0.74 Hz fault mode), ±80 V load dump protection, reverse battery protection, and lamp failure detection via flash frequency doubling. It operates across 8–18 V supply and drives electromechanical relays in dashboard and exterior indicator circuits.

For engineers reviewing the L9686 datasheet, L9686 pinout, L9686 application, or L9686 equivalent, key selection criteria include its integrated oscillator stability over battery voltage variation, shunt-based open-lamp detection threshold (65–95 mV), starter input sensing on Pin 8, output saturation voltage ≤1.7 V at 250 mA, and dual-package availability (SO8 and MiniDIP-8).

Technical Context

The L9686 integrates a precision two-mode oscillator whose frequency is set externally by R₁C₁, with temperature-compensated constants (K_N = 1.27–1.74, K_C = 0.53–0.74) enabling stable flash timing across –20°C to +100°C ambient. Its fault detection relies on current-sensing through an external shunt resistor (R_S), triggering frequency doubling when lamp current drops ~50%.

Protection architecture includes internal clamping (27–34 V), external R₃-based transient limiting (≥220 Ω required for ±80 V load dump), and reverse-battery blocking. The STARTER input (Pin 8) senses switch closure via R₂/R_lamp divider, initiating a 1.5 ms delay before relay actuation and oscillator enable.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage Range	8 V to 18 V - supports full automotive battery range including cold-crank and alternator transients.
Normal Flash Frequency	1.27–1.74 Hz - fixed by external R₁C₁; independent of battery voltage variation.
Fault Mode Flash Frequency	0.53–0.74 Hz - doubles relative to normal mode to visibly indicate lamp failure.
Output Saturation Voltage	≤1.7 V at 250 mA - ensures sufficient voltage headroom to reliably energize 12 V electromechanical relays.
Lamp Failure Threshold	65–95 mV across shunt - calibrated for 20 mΩ shunt; enables robust open-bulb detection under varying temperature and V_BAT.
Load Dump Protection	±80 V - requires external R₃ ≥ 220 Ω; handles ISO 7637-2 Pulse 5a/b transients.
Starter Input Sensing	Pin 8 detects S1 closure via R₂/R_lamp divider; initiates 1.5 ms delay before oscillator start.

Pinout & Package

Available in SO8 (ECOPACK® compliant) and MiniDIP-8 packages. Thermal resistance: SO8 = 180 °C/W, MiniDIP = 100 °C/W.

Pin/Terminal	Circuit Role	Design Meaning
1	GND	Power ground reference for all internal circuitry and output stage.
2	+VBATT	Main supply input; connects to vehicle battery via fuse and protection network (R₃, clamping diode).
3	OUTPUT	High-side switched output driving relay coil; sinks up to 250 mA with ≤1.7 V saturation.
4	OSCILLATOR	External timing node; connects to R₁C₁ network defining flash frequency.
5	STARTER	Switch-sense input; detects turn signal stalk closure via voltage divider (R₂/R_lamp).
6	FAULT DET.	Failure detection input; monitors shunt resistor (R_S) voltage to trigger frequency doubling.
7	NC	No connect - internally unconnected; must be left floating or tied to GND per layout guidelines.
8	OSCILLATOR	Secondary oscillator node; used with Pin 4 to configure timing network and temperature compensation.

Key Features

Feature	Design Value
Dual-frequency oscillator	Provides distinct flash rates (normal vs. fault) without external logic - enables immediate visual lamp failure indication.
Integrated lamp failure detection	Uses analog current sensing on shunt resistor; triggers frequency doubling at 65–95 mV threshold - eliminates need for microcontroller polling.
±80 V load dump tolerance	With external R₃ ≥ 220 Ω, survives ISO 7637-2 Pulse 5a/b - reduces need for additional TVS or suppressor components.
Voltage-independent timing	Oscillator frequency stable across 8–18 V supply - ensures consistent flash rate during cranking, charging, or battery sag.
Starter input with 1.5 ms delay	Pin 8 sensing initiates controlled relay activation after fixed delay - prevents contact chatter and relay coil stress at switch-on.

Applications

Front Turn Signal Control

Rear Turn Signal Control

Use Scenario: Driving front left/right directional lamps (e.g., amber bulbs on fenders or mirrors) synchronized with dashboard indicator.

IC Role / Device Role / Timing Role: Relay driver providing timed ON/OFF switching and automatic fault signaling via doubled flash rate.

Use Value: Ensures compliance with UNECE R6/SAE J595 flash timing requirements while detecting open filaments in real time.

Use Scenario: Controlling rear turn signal lamps (e.g., tail light assemblies) and side marker repeaters.

IC Role / Device Role / Timing Role: High-current relay interface with built-in lamp monitoring - replaces discrete transistor + comparator solutions.

Use Value: Reduces BOM count by integrating oscillator, sensing, and protection - improves system reliability in high-vibration environments.

Dashboard Indicator Interface

Handbrake Warning Lamp

Use Scenario: Driving instrument cluster warning lamps (e.g., left/right arrow LEDs or incandescent bulbs) reflecting turn signal status.

IC Role / Device Role / Timing Role: Synchronized output source feeding both exterior lamps and interior indicators - maintains timing correlation.

Use Value: Eliminates need for separate timing circuitry for dashboard; ensures identical flash phase and rate as exterior signals.

Use Scenario: Activating "handbrake engaged" warning lamp in combination with parking brake switch.

IC Role / Device Role / Timing Role: General-purpose warning lamp controller using same oscillator and fault-detection architecture.

Use Value: Reuses proven flash logic and protection design - accelerates development of auxiliary warning systems beyond turn signals.

Equivalent & Alternatives

The following parts are listed as comparable options for similar automotive warning lamp driver applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
UC2843BD	Current-mode PWM controller; no integrated lamp fault detection or dual-frequency logic.	Requires external comparators, timing resistors, and protection circuitry to replicate L9686 functionality.	Only suitable if full custom oscillator + sensing design is acceptable and cost-sensitive BOM allows added discretes.
TLE6232GP	High-side switch with embedded diagnostics; lacks dedicated oscillator and flash timing control.	Needs external microcontroller or 555 timer for flash generation; fault reporting via SPI, not visual frequency change.	Preferred where CAN-based diagnostics and programmable flash patterns are required - not drop-in for analog flasher replacement.

Compared with UC2843BD and TLE6232GP, the L9686 delivers fully autonomous flash control with visual lamp failure indication in a single 8-pin IC - reducing design effort, PCB area, and validation scope for traditional electromechanical turn signal systems.

Availability

L9686 is available at Aetrix Electronics and suitable for automotive lighting control, instrument cluster integration, and warning lamp subsystems requiring stable component supply and long-term industrial availability.

Supply support for L9686 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, power, and analog/mixed-signal ICs.

The L9686 belongs to ST's automotive analog power driver product line, engineered specifically for robust, low-complexity replacement of electromechanical flasher units in passenger and commercial vehicles.

FAQ

What external components are mandatory for basic L9686 operation?

The L9686 requires four mandatory external components: R₁ and C₁ to set oscillator frequency, R_S (20 mΩ shunt) for lamp current sensing, and R₃ (≥220 Ω) for load dump protection. R₂ is needed on Pin 8 for starter switch detection. No crystal, MCU, or additional logic is required.

How does the L9686 detect a failed bulb without a microcontroller?

The L9686 monitors voltage across the external shunt resistor (R_S) using an internal comparator. When lamp current drops ~50% due to filament breakage, the shunt voltage falls below the 65–95 mV threshold, causing the oscillator to switch from K_N to K_C mode - halving the flash period and doubling the visible flash frequency.

Can the L9686 drive LED turn signals directly?

No - the L9686 is designed to drive electromechanical relay coils (250 mA sink capability, ≤1.7 V saturation). LED loads require constant-current drivers or MOSFET switches. Using it with LEDs risks incorrect fault detection due to lower current draw and may violate thermal limits if relay coil is omitted.

Is the L9686 still in active production despite "Obsolete Product(s)" labels in the datasheet?

Yes - the "Obsolete Product(s)" header on each page reflects the 2003 document version, not the part's status. STMicroelectronics continues to list L9686 and L9686D in active distribution channels (e.g., Digi-Key, Mouser) with full technical support and no announced EOL notice as of latest public data.

L9686 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 8-DIP (0.300", 7.62mm)

Packaging:: Tube

Product Status:: Obsolete

Applications:: -

Current - Supply:: -

Voltage - Supply:: 8V ~ 18V

Operating Temperature:: -20°C ~ 100°C

Grade:: Automotive

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 8-Mini DIP

L9686 FAQ

1.How can I place an order for L9686 through Aetrix?

Please submit a Request for Quotation (RFQ) for L9686 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 L9686 reliable?

The price and inventory of L9686 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L9686 is usually 5 days.

3.What payment methods are accepted for L9686?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L9686 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L9686?

L9686 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L9686 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 L9686?

For technical support, including L9686 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L9686 requirements.

6.How does Aetrix verify that L9686 is sourced from the original manufacturer or authorized distributors?

All L9686 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 L9686 meets industry standards.

7.What is the process for return or replacement of L9686?

All L9686 units undergo pre-shipment inspection (PSI). If there is an issue with L9686, 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 L9686 part is unused and in its original packaging.

Return procedure for L9686:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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