US79 Series
CMOS Power Hall IC
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.
US79
US79
Temperature Suffix
K
K
Package
UA
8-Pin Narrow SOIC
Temperature Range
-40
o
C to 125
o
C
-40
o
C to 125
o
C
Functional Diagram
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擄C. Hall IC circuitry and
power FET output provide a low power dissipation
cool chip.
-
Voltage
Regulator
Control and
Protection
Hall Latch
+
1
Output 1
2
GND
3
Output 2
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.
MLX902xx Name of Sensor
IC
US79 CMOS Power Hall
Rev Y.X
Rev 3.0
22/Aug/98
23/Jan/01
Page
Page 1
1
1
2
3
4
