US651 / US661
Two-Coil Low Noise Fan Driver
Features and Benefits
Soft Switching for low noise applications
Slope control setting by dedicated pin
One-chip solution
(Hall + Drivers)
Advanced Protection
(enhanced locked rotor,
reverse voltage, thermal, output clamping)
Application Examples
5V/12V DC brushless motors
Continuous output current up to 350mA
Low noise brushless cooling fans
PC, server, laptop cooling fan
Power supply cooling fan
Large and small fan size
Integrated tachometer (US651) or
alarm (US661) signal output
Ordering Information
Part No.
US651
US661
Temperature Code
E (-40° to 85°
C
C)
E (-40° to 85°
C
C)
Package Code
DC (8-pin narrow SOIC8)
DC (8-pin narrow SOIC8)
1 Functional Diagram
2 General Description
The US651/661 is a one-chip solution for driving
two-coil brushless DC fan and motors. It is
especially suitable for relatively high-current rated
operation as it can drive up to 350mA continuous
output current.
The use of Melexis Soft Switching concept lowers
the acoustic and electrical motor noise and
provides smoother operation. This efficient
solution is combined with an innovative slope
control design controllable via a dedicated pin.
The device includes reverse voltage protection,
locked rotor protection and thermal protection.
Therefore, the IC robustness perfectly suits for
consumer and automotive-on-board applications.
Tachometer (FG) or Alarm (RD) open-drain output
is available. It makes the connectivity with external
interface such as hardware monitoring or Super
I/O IC easier.
The device is delivered in RoHS compliant DC
package (SMD) for automatic soldering
390109020902
Rev 002
Page 1 of 12
Preliminary Datasheet
Mar/07
MELEXIS [ Melexis Microelectronic Systems ]
