MELEXIS US79K Datasheet

MLX902xx Name of Sensor Rev Y.X 22/Aug/98 Page 1

US79 Series

CMOS Power Hall IC

US79 CMOS Power Hall IC Rev 3.0 23/Jan/01 Page 1

Features and Benefits

ESD Tolerance IC>7,000V
ESD Tolerance of Fan >15,000V
Built-in Reverse Voltage Protection
Built-in RFI Filter
Power Efficient CMOS and Power MOSFET Drivers allow 400mA without overheating
Built-in Zener Diodes Protect Outputs
Eliminates all Fan Components
Eliminate PC Board
5V and 12V Operation
High Sensitivity for switching symmetry
Locked Rotor Shutdown

Applications

Fan Sizes up to 90mm
Current Range up to 400mA

Ordering Information

Part No. Temperature Suffix Package Temperature Range
US79 K UA -40oC to 125oC
US79 K 8-Pin Narrow SOIC -40oC to 125oC

Description

The US79KUA is the most advanced Smart Fan
Control Hall IC. It is designed for 5V and 12V cooling
commutation. The chip contains many features to
allow survival in a harsh environment. The IC was
designed to eliminate all discrete components such
as capacitors, resistors, transistors, diodes, PC
board and associated labor, replacing US$0.25 to
US$0.35 in direct cost.

The K rating guarantees proper operation up to an
ambient temperature of 125°C. Hall IC circuitry and
power FET output provide a low power dissipation
cool chip.

Locked Rotor conditions are detected by the IC when
there is no motion for one second and will shut off
the motor drive for five seconds. Then, the IC will
turn on the drive current for one second. This
sequence continues indefinitely until the locked rotor
condition is fixed. This feature prevents overheating.
Maximum ambient temperature is determined by
driver power dissipation. For instance, at 125C
ambient, driver power cannot exceed 125mW or
250mA. Future versions will offer optional features.

Functional Diagram

Voltage

Regulator

1 2 3

Hall Latch

Output 1 Output 2

Control and

Protection

GND

-+

US79 Series

CMOS Power Hall IC

US79 CMOS Power Hall IC Rev 3.0 23/Jan/01 Page 2

US79 Electrical Specifications

DC operating parameters: TA = 25 to 125oC, VDD = 5.0 to 12V unless otherwise specified.

Parameter Test Conditions Min Typ Max Units

Supply Voltage V

DD

Operating 3.7 - 18 V

Supply Current I

DD

Operating 1.2 2.0 4 mA

Output leakage I

LEAK

B<B

OP

- 1 10 µA

Output voltage V

OUT

B<B

HYS

- - 35 V

Output Saturation voltage V

DSS IOUT

= 150mA, VDD = 12V 400 600 mV

Output Saturation voltage V

DSS IOUT

= 350mA, VDD =12V 800 1100 mV

Output On resistance R

DDSS VDD

= 12V 1.34 Ω

Thermal resistance R

th

Operating 200 °C/Watt

US79 Magnetic Specifications

DC operating parameters: TA = 25 to 125oC, VDD = 5.0 to 12V unless otherwise specified. 1 mT = 10 Gauss.

Parameter Symbol Test Conditions Min Typ Max Units

Operate Point B

OP

Operating 3.0 6.0 mT

Release Point B

RP

Operating -6.0 -3.0 mT

Hysteresis B

HYS

Operating - 6.0 - mT

General Description

The US79 eliminates 16 solder joints, protects
against ESD, filters RFI emission caused by
switching of high currents, protects against voltage
surges, protects against locked rotor, operates at a
low temperature and is manufactured in an
Automotive IC factory.

Unique Features

Reverse voltage protection eliminates the need for a
diode. Reverse current flows through the coils and
the chip. Power dissipation is (2 * Istall/start * 0.7V).
Table 1 presents max temperature for each current.

Table 1

I

stall

/ I

start

TA Maximum Rev V Test

100mA 125°C
200mA 100°C
300mA 70°C
400mA 40°C

The IC tolerates >7000V ESD. When installed in the
fan, the windings increase the ESD tolerance to
>15000V eliminating the need for ESD concerns in
the finished fan. Reverse Voltage protection is
provided by the motor windings. The IC contains
slew rate control on the output drivers to eliminate
RF emissions. 35V Zener diodes clamp the output
drivers for overstress protection.

Application Comments

EMC protection is built in. EMC considerations
require that the fan assembly should tolerate ESD,
reverse voltage, over voltage and not radiate RF
noise which may interfere with other electronic
equipment. These capabilities are built in to the chip
to meet EMC requirements.

Qualification Test Results

SOA (Safe Operating Area) tests to verify inductive
switching of 500mA @ 20V. 1000 pieces tested 100
cycles each. Operating Life Test at TA = 150C for
4000 hrs. 100pc. “0” failures. Package qualified to
QS900 automotive PPAP specifications.