The LB11851FA provides an interface between a microcontroller motor control signal and external MOS transistors.
This device can implement a microprocessor fan driver with a minimal number of external components. The
LB11851FA is optimal for server and personal computer microprocessor fan drive in response to temperature or other
external signals when high precision and high air flow are required.
Features
•
Fan motor interface driver function (FGIN)
⇒
This IC accepts a signal from a microcontroller and interfaces to external power transistors (PMOS and NMOS) to
provide high-efficiency low-power single-phase full-wave drive.
•
Variable speed input pin (PWMIN)
⇒
PMOS side PWM control
NMOS side current regeneration using slow decay is used to achieve quite high-speed control.
•
Built-in kickback absorption circuit (OUT1P/2P)
⇒
This circuit absorbs the kickback current that is generated at phase switching or power on/off to achieve smooth
current regeneration and protect the external transistors against destruction or degradation.
•
Built-in current limiter circuit (SENSE)
⇒
This circuit implements a chopper-type current limiting control that operates at startup and during lock protection
mode.
The current detection voltage is set to a fixed 0.2V internally.
•
Built-in microcontroller power supply (5VREG)
Semiconductor Components Industries, LLC, 2013
May, 2013
71112 SY 20120702-S00002 No.A2092-1/5
LB11851FA
Specifications
Absolute Maximum Ratings
at Ta
=
25°C
Parameter
Maximum supply voltage
OUTN pin maximum output current
OUTP pin maximum output current
OUT pin voltage handling capacity
5VREG maximum output current
Allowable power dissipation
Operating temperature
Storage temperature
Symbol
VCC max
IOUTN max
IOUTP max
VOUT max
I5VREG max
Pd max
Topr
Tstg
When mounted on the specified circuit board *1
*2
Conditions
Ratings
18
20
20
18
20
400
-40 to +90
-55 to +150
Unit
V
mA
mA
V
mA
mW
°C
°C
*1 Specified substrate :20.0mm ×10.0mm ×0.8mm, Paper phenol board.
*2 Do not exceed Tj max = 150°C
Caution 1) Absolute maximum ratings represent the value which cannot be exceeded for any length of time.
Caution 2) Even when the device is used within the range of absolute maximum ratings, as a result of continuous usage under high temperature, high current,
high voltage, or drastic temperature change, the reliability of the IC may be degraded. Please contact us for the further details.
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating
Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability.
Recommended Operating Ranges
at Ta
=
25°C
Parameter
Supply voltage - VCC
PWM high-level input voltage range
PWM low-level input voltage range
FGIN high-level input voltage range
FGIN low-level input voltage range
SENSE input voltage range
Symbol
VCC
VPWMINH
VPWMINL
VFGINH
VFGINL
VSENop
Conditions
Ratings
6 to 16
2.1 to 5.0
0 to 0.4
2.1 to 5.0
0 to 0.3
0 to 5.0
Unit
V
V
V
V
V
V
Electrical Characteristics
at Ta
=
25°C, VDD = 12V
Parameter
Circuit current
5VREG voltage
SENSE pin detection voltage
FGIN high-level input current
FGIN low-level input current
PWMIN high-level current
PWMIN low-level current
OUT1P, OUT2P high-level output
voltage
OUT1P, OUT2P low-level output
voltage
OUT1N, OUT2N high-level output
voltage
OUT1N, OUT2N low-level output
voltage
*1 : There is a built-in 100Ω gate protection resistor.
VO12NL
VO12NH
VO12PL
Symbol
ICC1
5VREG
VSENth
FGIhi
FGIlow
PWMIhi
PWMIlow
VO12PH
VIN = 3V
VIN = 0V
VIN = 3V
VIN = 0V
IO = 10mA *2
IO = 1mA *2
IO = 10mA *2
IO = 1mA *2
IO = 10mA *1
IO = 1mA *1
IO = 10mA *1
IO = 1mA *1
*2 : There is a built-in 300Ω gate protection resistor.
9
10.8
0.1
With no load
5VREG = 10mA
Conditions
min
3.5
4.8
0.15
60
-27
35
-27
10
11
3
Ratings
typ
5
5
0.19
80
-21
45
-21
11
11.3
4
1.2
10
11.1
1
0.7
2
1
5
1.5
11.9
max
6.5
5.2
0.23
100
-15
55
-14
11.9
mA
V
V
μA
μA
μA
μA
V
V
V
V
V
V
V
V
Unit
Truth Table
FGIN
L
H
L
H
L
H
L
H
H
L
PWMIN
L
SENSE
L
OUT1P
L
H
H
H
H
H
OUT1N
L
H
L
H
L
H
OUT2P
H
L
H
H
H
H
OUT2N
H
L
H
L
H
L
OUT1
→
2 drive
OUT2
→
1 drive
Regeneration mode
(low side regeneration)
Current limiter
(low side regeneration)
Mode
Note 1 : For the SENSE pin, the "H" state is 0.2V or higher.
Note 2 : The IC goes to regeneration mode (no motor drive applied) when the microcontroller is reset (the output high-impedance state).
No.A2092-2/5
LB11851FA
Package Dimensions
unit : mm (typ)
3428
OUT2P
3.0
10
Pin Assignment
1
2
3
4
5
Top View
10
9
OUT1P
OUT1N
VCC
SENSE
GND
OUT2N
5VREG
3.0
4.9
LB11851FA
8
7
6
0.55
FGIN
PWMIN
1 2
0.5
0.25
1.03
0.16
0.5
Pd max -- Ta
Specified Substrate : 20.0
×
10.0
×
0.8mm
3
Paper phenol
Allowable power dissipotion, Pd max - W
0.1
0.4
SANYO : Micro10
0.3
0.2
0.19
0.1
0
-40
-20
0
20
40
60
80
100
120
Ambient temperature, Ta - C
Block Diagram
VCC
OUT1N
5VREG
5VREG
100Ω
5VREG
Controller
PWMIN
5VREG
OUT2N
FGIN
100Ω
300Ω
20kΩ
20kΩ
OUT2P
300Ω
20kΩ
OUT1P
20kΩ
SENSE
GND
No.A2092-3/5
LB11851FA
Application Circuit Example (12V)
VM=Line
1P
2P
1N
2N
RF
VCC
5VREG
VDD
SENSE
LB11851FA
PWMOUT
H
IN-
FGOUT
IN+
Microcontroller
PWMIN
OUT2P
OUT2N
2P
2N
FGIN
OUT1P
PWMIN
INPUT
A/D
VSS
FG
GND
OUT1N
1P
1N
No.A2092-4/5
LB11851FA
1. Power supply (VCC and VM) and ground
The wiring is separated into the control IC side (VCC line) and the motor output side (VM line) by the diode DI, which
protects the IC from destruction on reverse connection. The application circuit uses 1μF capacitors to prevent line
oscillation when kickback occurs. Similarly, 1μF capacitors are also used on the VCC line for power supply line
stabilization.
2. PWMIN
The LB11851M accepts an open-drain output signal from the microcontroller with this pin and controls the on/off
states of the PMOS transistor (OUT1P and OUT2P) outputs accordingly. A constant-current bias is provided from
5VREG internally to the IC.
3. FGIN
The LB11851M accepts a CMOS output from the microcontroller with this pin and determines the drive phase output
(OUT1P, OUT2P, OUT1N, or OUT2N).
4. 5VREG
This is the power supply for the microcontroller, Hall effect sensors, and other circuits. A capacitor with a value of
1μF is used for output stabilization. This pin has an output current capacity of 20mA.
5. SENSE
A sensing resistor is used for current detection. If the SENSE pin voltage exceeds 0.2V, the PMOS transistors are
turned off and only low side regeneration is performed.
*<OUT1, 2P output H voltage / OUT1, 2N output L voltage>
Output L voltage of OUT1 and 2 sticks in GND when FET is put up outside like the example of applied circuit by
internal pull-down resistor (20KΩ), and there is no what turns on FET.
Output H voltage of OUT1 and 2 sticks in VCC with internal pull-up resistor (20kΩ) as the Pch side is also similar.
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