January 16, 2006

Heavy current (60A) in a compact surface-mount package SI-5201
A semiconductor relay optimal for automotive applications.
Its low thermal resistance and low power loss realizes
a compact and stable system.

Sanken Electric has developed the SI-5201 semiconductor relay capable of replacing conventional mechanical relays (mechanical switches) for medium to heavy current loads such as headlights, wipers, fans, etc.
Samples will be available from January 26, CY06. Mass shipment will be launched in the second half of CY06 starting with 100k pcs/month, then ramping up to 1,000k pcs/month by CY08.
(Sample price: 800 Yen)

1. Development background and product overview
  Although automotive electronification has been progressing rapidly in recent years, conventional mechanical relays are still used widely for medium to heavy current loads (30-60A) such as headlights, wipers, fans, etc.
Mechanical relays, however, changing outputs via contacts (by electromagnets), make structurally clicking noises, have short lifetimes due to wear and deterioration, and are difficult in downsizing, resulting in restrictions on installing locations in vehicles and on control methods. This has been hindering adequate functional improvements.

Sanken has, thus, developed the SI-5201 semiconductor relay having no movable parts, featuring a stabilized relay operation and longer lifetime and assuring improved reliability.

The SI-5201 has adopted a compact surface mount package with a low thermal resistance, realizing a downsizing of a system capacity in size and weight. Additionally, diverse built-in protection functions contribute to improving a stability of the system controlling headlights, wipers, etc.

The SI-5201 has employed a separate 2-chip structure consisting of a MOSFET chip and a control IC chip, realizing a MOSFET on-resistance as low as 7mΩ by configuring an optimal process for each chip.
The MOSFET incorporates a current-detecting sense-MOSFET and a heat-detection diode on it, improving its detection accuracy.
The control IC integrates MOSFET drive circuits, diverse protection circuits, an output current monitor function, a self-diagnosis output function, etc., by utilizing Sanken proprietary BCD process.
2. Features
A heavy 60A output current in a compact surface mount package.
Realizes a current as heavy as 60A by combining a low on-resistance MOSFET (7mΩ), limiting a power loss (heat), and a low thermal-resistance (1.1°C/W) package (TO220S-7, resin unit dimensions: 10mm x 10mm x 3.7mm).
Low standby current (5μA)
Realizes a reduced consumption current of batteries in standby mode, where no signal input at the IN terminal.
Built-in output current monitor and self-diagnosis output functions
Send out the operating conditions and failure diagnosis signals to a microprocessor. And enables the microprocessor to monitor precise system conditions and to detect malfunctions.
Built-in functions for overcurrent protection, thermal shutdown protection and overvoltage protection, and battery reverse-connection protection circuit
Improve the safer operation of the system by the protection function that stops the IC operation on system malfunction.
3. Application
Relays for headlights, taillights, wipers, power windows, sunroofs, fans, etc.
4. Major specifications
Electrical characteristics
Parameter Symbol Rating Unit
Operating power supply voltage VBB 30 max V
Output current (DC) Io 60 max A
Output current (pulse) Io(pulse) 120 max A
Output on-resistance RDS(ON) 7 typ
Quiescent circuit current Iq 5 typ μA
Protection circuits
  1. Overcurrent protection circuit: Applicable for wider load ranges thanks to a selective protection-starting-current of 60A and 30A by an external signal input.
  2. Thermal shutdown function: Protection start temperature = 151°C (Min)
  3. Overvoltage protection function: Protection start voltage = 30V(Min)
  4. Battery reverse-connection protection circuit
Self-diagnosis function
Outputs a signal when the overcurrent protection or the thermal shutdown protection is activated.
Output current monitoring function
Applicable for an output-current monitoring or an open-load detection by a feedback current via the DG terminal proportional to an output current at normal operation.

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