US72/73
Single Coil Fan Driver
1. Glossary of Terms
Full Bridge: Two output drivers that can both source or sink current. When a load is placed between the
drivers, current can flow through the load in both directions.
FG: The Frequency Generator or tachometer signal; provides one pulse for every magnetic pole
RD: The Rotation detection or Lock Alarm signal is high when the rotor is blocked or spinning very slowly.
MilliTesla (mT), Gauss: Units of magnetic flux density; 1 milliTesla = 10 Gauss
Single Coil Fan: a fan with only one coil winding, usually requiring a bipolar or full-bridge driver
Locked rotor: The condition of a fan that has stopped spinning due to mechanical blockage
2. Absolute Maximum Ratings
Supply Voltage, V
DD
(overvoltage)
Output Voltage, FG or RD
Output Current, I
OUT
Operating Temperature Range, T
A
Junction Temperature, T
j
Storage Temperature, T
s
ESD Sensitivity (AEC Q100 002)
Magnetic Flux Density
28V
28V
500mA
-40 to 85°C
125°C
-55 to 150°C
2KV
No limit
Exceeding the absolute maximum ratings may cause permanent damage. Exposure to absolute-
maximum-rated conditions for extended periods may affect device reliability.
3. US72/73 Electrical Specifications
DC Operating Parameters T
A
= 25 C, V
DD
= 12V (unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
o
Max
Units
Supply Voltage
Supply Current
On Resistance
Bridge Current
Bridge Current
Thermal Resistance
Locked-Rotor Period
Locked-Rotor period
Freewheel Switching delay
FG/RD Output Leakage
FG/RD On voltage
V
DD
I
DD
R
dson
I
load
I
load
R
th
t
on
t
off
t
fw
I
off
V
dson
Operating
V
DD =
24V, No Load
Full bridge, R
nmos
+ R
pmos
Peak
Continuous
one-sided PCB, zero LFPM
4.5
4
3
28
6
5.3
500
350
150
0.25
1.25
200
Volts
mA
Ohms
mA
mA
o
C/Watt
S
S
uS
10
0.5
uA
Volts
V
out
= 24V
Iout = 5mA
3901090261
Rev. 002
Page 3 of 9
Data Sheet
May/04
MELEXIS [ Melexis Microelectronic Systems ]
