1
SEMICONDUCTORS
DESCRIPTION
The ZXBM2004 is a 2-phase, DC brushless motor pre-driver with PWM
variable speed control suitable for fan and blower motors. The controller is
primarily intended for thermal control using a thermistor but can also be used
for control using an external voltage or PWM signal.
FEATURES
•PWM Speed control via external thermistor
•Ability to be able to set a minimum speed
•Ability to be able to remove any speed change against supply voltage variation
•Low noise
•Built in lock detect protection, rotational speed sensing and automatic recovery
•Built in Hall amplifier allows direct connection to Hall element
•Speed (FG) pulse output
•Rotor lock (RD) output
•Up to 18V input voltage (60V with external regulator)
•SO14N and QSOP16 package options
APPLICATIONS
•Mainframe and Personal Computer Fans and Blowers
•Instrumentation Fans
•Central Heating Blowers
•Automotive climate control
DEVICE MARKING
ZETEX
ZXBM2004
Date code
ZXBM2004
PROVISIONAL ISSUE E - APRIL 2003
VARIABLE SPEED 2-PHASE FAN MOTOR CONTROLLER FOR
THERMISTOR CONTROL
DEVICE REEL SIZE TAPE WIDTH QUANTITY PER REEL
ZXBM2004N14TA 7" (180mm) 16mm 500
ZXBM2004N14TC 13" (330mm) 16mm 2,500
ORDERING INFORMATION - SO14N
SO14
DEVICE REEL SIZE TAPE WIDTH QUANTITY PER REEL
ZXBM2004Q16TA 7" (180mm) 12mm 500
ZXBM2004Q16TC 13" (330mm) 12mm 2,500
ORDERING INFORMATION - QSOP16
QSOP16
ZXBM2004
SEMICONDUCTORS
PROVISIONAL ISSUE E - APRIL 2003
2
PARAMETER SYMBOL MIN TYP MAX UNIT CONDITIONS
Supply Voltage VCC 418V
Supply Current ICC 5 6.8 mA No Load 1
Hall Amp Input Voltage VIN 40 mV diff p-p
Hall Amp Common Mode Voltage VCM 0.5 Vcc-1.5 V
Hall Amp Input Offset VOFS ±7 mV
Hall Amp Bias Current IBS 350 nA
PH1, PH2 Output High VOH VCC -2.2 VCC -1.8 V IOH =80mA
PH1, PH2 Output Low VOLA 0.4 0.6 V IOL =20mA 2
PH1, PH2 Output Low VOLB 0.4 0.6 V IOL =50A3
PH1, PH2 Output Source Current IOH -80 mA
PH1, PH2 Output Sink Current IOL 20 mA
CPWM Charge Current IPWMC -3.6 -4.3 -5.0 A
CPWM Discharge Current IPWMD 50 62 75 A
CPWM High Threshold Voltage VTHH 1V
CPWM Low Threshold Voltage VTHL 2V
PWM Frequency FPWM 24 kHz CPWM = 0.15nF
ThRef Voltage VThReF 1.94 1.96 2 V IOL =100A
SMIN Output Current IOSMIN -25 -30 -35 A
SPD Voltage Minimum VSPDL 1 V 100% PWM Drive
SPD Voltage Maximum VSPDH 2 V 0% PWM Drive
SPD Open Circuit Voltage VSPDOC 1.5 V 4
CLCK Charge Current ILCKC -3.0 -3.8 A
CLCK Discharge Current ILCKD -0.38 -0.45 A
CLCK High Threshold Voltage VTHH 1V
CLCK Low Threshold Voltage VTHL 2V
Lock condition On:Off ratio 1:10
Notes:
1. Measured with pins H+, H-, CLCK and CPWM = 0V and all other signal pins open circuit.
2. Measured when opposing Phase Output is Low
3. Measured when opposing Phase Output is High
4. This voltage is determined by an internal resistor network of 52.5K⍀from the pin to Gnd and 19.5K⍀from the pin to a 2V reference.
The resistor values are subject to a ±20% manufacturing tolerance.
ELECTRICAL CHARACTERISTICS (at Tamb = 25°C & Vcc = 12V)
PARAMETER SYMBOL LIMITS UNIT
Supply Voltage VCCmax -0.6 to 20 V
Input Current ICCmax 200 mA
Power Dissipation PDmax 500 mW
Operating Temp. TOPR -55 to 110 °C
Storage Temp. TSTG -55 to 125 °C
ABSOLUTE MAXIMUM RATINGS
ZXBM2004
SEMICONDUCTORS
PROVISIONAL ISSUE E - APRIL 2003
3
BLOCK DIAGRAM
Vcc
SPD
H+
H-
Gnd
Ph1
Ph2
C
PWM
C
LCK
FG
ZXBM2004
SOIC14
RD
V+OP
ThRef
S
MIN
1
Vcc
SPD
H+
H-
Gnd
Ph1
Ph2
C
PWM
C
LCK
FG
ZXBM2004
QSOP16
RD
V+OP
ThRef
S
MIN
N/C
N/C
1
PIN ASSIGNMENTS
PIN FUNCTIONAL DESCRIPTION
H+ - Hall input
H- - Hall input
The rotor position is detected by a Hall sensor whose
output is applied to these pins. This sensor can be
either a 4 pin 'naked' Hall device or of the 3 pin buffered
switching type. For a 4 pin device the differential Hall
output signal is connected to the H+ and H- pins. For a
buffered Hall sensor the Hall device output is attached
to the H+ pin, with a pull-up attached if needed, whilst
the H- pin has an external potential divider attached to
hold the pin at half Vcc. When H+ is high in relation to
H-, Ph2 is the active drive.
ThRef - Thermistor network reference
This is a reference voltage of nominal 1.96V. It is
designed for the ability to 'source' current into the
thermistor network therefore it will not 'sink' any
current from a higher voltage.
SPD - Thermistor network input
The thermistor network is attached to this pin. The
resultant thermistor network voltage applied to the
SPD pin provides control over the Fan Motor speed by
varying the Pulse Width Modulated (PWM) drive ratio
at the Ph1 and Ph2 outputs. The control signal takes the
form of a voltage input of range 2V to 1V, representing
0% to 100% drive respectively.
In normal operation a 10k⍀NTC thermistor network as
shown in the Block Diagram would be attached to the
SPD pin, however for simplicity of use it is possible to
attach an 100k⍀NTC thermistor directly to the pin. The
pin has an internal potential divider between Gnd and
an internal 1.96V reference designed to hold the pin at
approximately 1.5V. This will represent a drive of
nominally 50%. The addition of the 100k⍀NTC
thermistor from the SPD pin to ground will provide a
drive nominally 70% at 25°C and 100% at 50°C.
If speed control is not required this pin can be left open
circuit for 50% drive or tied to ground to provide 100%
drive.
If required this pin can also be used as an enable pin.
The application of a voltage >2.0V will to force the PWM
drive fully off, in effect disabling the drive.
CPWM - Sets PWM frequency
This pin has an external capacitor attached to set the
PWM frequency for the Phase drive outputs. A
capacitor value of 0.15nF will provide a PWM
frequency of typically 24kHz.
The CLCK timing period (TPWM) is determined by the
following equation:
()()
T=
V-VxC
I
V-VxC
I
PWM
THH THL
PWMC
THH THL
PWMD
+
Where: C = CPWM +15 - in pF
VTHH and VTHL are the CPWM pin
threshold voltages
IPWMC and IPWMD are the charge and
discharge currents in A.
TPWM in S
As these threshold voltages are nominally set to VTHH =
2V and VTHL = 1V the equations can be simplified as
follows:
T=
C
I
C
I
PWM
PWMC PWMD
+
SMIN - Sets Minimum Speed
When using a thermistor to control a fan’s speed it is
possible that at low temperatures the fan might fail to
start or if already running and the temperature drops
the fan might stop. This is an undesirable condition to
have in thermal controlled fans so the SMIN pin is used
to set a minimum speed. The following graph
illustrates a typical speed response characteristic for a
thermally controlled fan.
ZXBM2004
SEMICONDUCTORS
PROVISIONAL ISSUE E - APRIL 2003
4
When a resistor is attached from this pin to Gnd it sets a
voltage on the pin. This voltage is monitored by the
SPD pin such that it cannot rise above it. As a higher
voltage on the SPD pin represents a lower speed it
therefore restricts the lower speed range of the fan. If
this feature is not required the pin is left open circuit so
no minimum speed will be set.
If the fan is being controlled from an external voltage
source either this feature should not be used or if it is
required then a >1k⍀resistor should be placed in series
with the SPD pin.
The following equation is used to set the voltage on the
SPD pin and thus minimum speed. Note that the actual
minimum speed will be a function of the motor
mechanics.
V=I xR
SMIN OSMIN SMIN
Where: VSMIN is the voltage on pin SMIN that
represents the maximum voltage on
the SPD pin in turn representing the
minimum speed.
IOSMIN is in mA
RSMIN is in k⍀and
VSMIN is in V
GND - Ground
This is the device supply ground return pin and will
generally be the most negative supply pin to the fan.
CLCK - Locked Rotor timing capacitor
Should the fan stop rotating for any reason, i.e. an
obstruction in the fan blade or a seized bearing, then
the device will enter a Rotor Locked condition. In this
condition after a predetermined time (TLOCK) the RD pin
will go high and the Phase outputs will be disabled.
After a further delay (TOFF) the controller will re-enable
the Phase drive for a defined period (TON) in an attempt
to re-start the fan. This cycle of (TOFF) and (TON) will be
repeated indefinitely or until the fan re-starts.
The frequency at which this takes place is determined
by the size of the capacitor applied to this CLCK pin. For a
12V supply a value of 1uF will typically provide an 'On'
(drive) period of 0.26s and an 'Off' (wait) period of 2.6s,
giving an On:Off ratio of 1:10.
The CLCK timing periods are determined by the
following equations:
()
T=
VxC
lT=
V-VxC
I
LOCK THH LCK
LCKC
ON
THH THL LCK
LCKC
()
T=
V-VxC
I
OFF
THH THL LCK
LCKD
Where: VTHH and VTHL are the CLCK pin
threshold voltages and
ILCKC and ILCKD are the charge and
discharge currents.
As these threshold voltages are nominally set to VTHH =
2V and VTHL = 1V the equations can be simplified as
follows:
T=
2xC
IT=
C
IT=
C
LOCK LCK
LCKC
ON LCK
LCKC
OFF LCK
LCKD
I
ZXBM2004
SEMICONDUCTORS
PROVISIONAL ISSUE E - APRIL 2003
5
-10 0 10 20 30 40 50 60 70
0
10
20
30
40
50
60
70
80
90
100
Set Minimum Speed
Typical Temperature Response
Fan speed (%)
Temperature (˚C)
RD - Locked Rotor error output
This pin is the Locked Rotor output as referred to in the
CLCK timing section above. It is high when the rotor is
stopped and low when running.
This is an open collector drive giving an active pull
down with the high level being provided by an external
pull up resistor.
FG - Frequency Generator (speed) output
This is the Frequency Generator output and is a
buffered signal from the Hall sensor.
This is an open collector drive giving an active pull
down with the high level being provided by an external
pull up resistor.
PH1 - Phase 1 External transistor driver
PH2 - Phase 2 External transistor driver
These are the Phase drive outputs and are darlington
emitter follower outputs with an active pull-down to
help faster switch off when using bipolar devices. The
outputs are designed to provide up to 80mA of drive
when high to the base or gates of external transistors
as shown in the Typical Application circuit following.
The external transistors in turn drive the fan motor
windings.
In addition the active Phase drive is capable of sinking
up to 20mA when driving low to aid turn off times
during PWM operation. When the Phase is inactive the
output is held low by an internal pull-down resistor
V+OP - Phase Outputs supply voltage
This pin is the supply to the Phase outputs and will be
connected differently dependant upon external
transistor type.
For bipolar devices this pin will be connected by a
resistor to the VCC pin. The resistor is used to control
the current into the transistor base so its value is
chosen accordingly.
For MOSFET devices the pin will connect to the VCC pin
VCC - Applied voltage
This is the device internal circuitry supply voltage. For
5V to 12V fans this can be supplied directly from the
Fan Motor supply. For fans likely to run in excess of the
18V maximum rating for the device this will be
supplied from an external regulator such as a Zener
diode.
RD and FG Timing Waveform:
Lock Timing Example:
Using the equation previously described and to be
found under the CLCK pin description:
T=
2xC
IT=
C
IT=
C
LOCK LCK
LCKC
ON LCK
LCKC
OFF LCK
LCKD
I
Using a value of CLCK = 1.0uF together with the values
of ILCKC and ILCKD to be found in the Electrical
Characteristics we can derive the following timings for
operation at 12V and 25°C:
T=
2x1uF
3.8 A = 0.526s T = 1uF
3.8 A
LOCK ON
=023.6
s
T=1uF
0.38 A
OFF =263.
s
ZXBM2004
SEMICONDUCTORS
PROVISIONAL ISSUE E - APRIL 2003
6
APPLICATIONS INFORMATION
This section is intended to give a brief insight into using
the ZXBM2004. More complete data covering all
applications aspects of this and other ZXBM series of
fan motor pre-drivers is available from the Zetex
website www.zetex.com or from your nearest Zetex
office.
The ZXBM2004 device is a development of the
ZXBM2001 to ZXBM2003 series of fan motor controller
that has been specifically developed for use in
thermistor temperature control situations. The main
feature of the device is the ability to set a minimum
speed at which the fan will run.
Two application circuits are illustrated here and both
show slightly differing ways in which the ZXBM2004
controller can be used. For example Figure 1 employs
bipolar driver transistors and a naked Hall device whilst
the Figure 2 employs MOSFET devices, a buffered Hall
device and speed vs supply change normalisation.
These differing features will be described in detail in
the following sections.
The Phase Outputs
The Phase outputs on the ZXBM2004 2-phase DC
brushless motor pre-driver have been designed to be
capable of driving both Bipolar or MOSFET power
transistors. The output stage consists of both active
pull-up and active pull-down devices for optimum
PWM switching. Pulling up, the output can deliver a
maximum of 80mA whilst pulling down, sinking 20mA
is possible. This is particularly useful for driving bipolar
devices where for fast turn-off it is important to remove
base stored charge as quickly as possible.
Figure 1 shows an Application Circuit for driving
bipolar devices. The normal practice when driving a
bipolar device would be to use a base series resistor to
control and limit the current into the base. However the
problem with this would be that the resistor would also
restrict the removal of the base stored charge at
switch-off. In order to keep turn-off times as short as
possible it is therefore preferable to remove the base
resistor and apply the current limiting in the supply to
the output stage. This is not too dissimilar from the
approach taken by conventional Totem-pole output
stages in TTL devices.
In the case of the ZXBM2004 the current limiting is
applied by inserting a resistor from V+OP to the VCC
pin. The current applied to the base is determined by:
()
R5 = V - V+0.7
I
CC
OH
Out
Where: VOH is the Phase Drive Output High
Voltage.
IOut is the drive required to the external
Phase Drive transistors
The circuit example in Figure 1 has the external drive
(IOut) set to 34mA.
ZXBM2004
SEMICONDUCTORS
PROVISIONAL ISSUE E - APRIL 2003
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When driving MOSFETs a more conventional
approach is employed in that each MOSFET will have a
gate limiting resistor to control turn-on and turn-off.
The V+OP pin will then be connected directly to the
supply i.e. the Vcc pin. Figure 2 illustrates this.
ZXBM2004
SEMICONDUCTORS
PROVISIONAL ISSUE E - APRIL 2003
8
ZXBM2004
Ph1
Ph2
VCC
Gnd
H+
H-
CPWM
CLCK
SPD
RD
12V
Q1
W1
C1
C2
C3
1µF
150pF
1µF
ZD1
47V
Q2
W2
ZD2
47V
C5 2.2µF
FCX
1053A
D1
D2
1N4148
1N4004
Hall
0V
FG
C4
0.1µF
R8
RTherm
10kΩ
NTC
2kΩR3 280Ω
V+OP
FG
ThRef
SMIN
RD
R4
39kΩ
R6
2kΩ
R5
3.3kΩ
FCX
1053A
Figure 1: Typical Application Circuit utilising Bipolar power transistors and a Naked Hall device.
ZXBM2004
Ph1
Ph2
VCC
Gnd
H+
H-
CPWM
CLCK
SPD
RD
12V
Q1
R1
W1
C1
C2
C3
1µF
100Ω
150pF
1µF
ZXMN
6A07Z
ZD1
D3
47V
1N4148 Q2 R2
W2
100Ω
ZD2
D4
47V
1N4148
C5 2.2µF
ZXMN
6A07Z
D1
D2
1N4148
1N4004
Hall
0V
FG
C4
0.1µF
RTherm
10kΩ
NTC
V+OP
FG
ThRef
SMIN
RD
R4
43kΩ
R6
100kΩ
R7
1.6kΩ
R5
3.3kΩ
R9
R8
R10
33kΩ
33kΩ
33kΩ
Figure 2: Typical Application Circuit utilising MOSFET power transistors and a bufferred Hall device.
Thermal Control
The ZXBM2004 has been specifically designed for use
in thermal control applications where a thermistor is
employed for temperature sensing.
The simplest way in which the controller can be used is
by attaching a 100k⍀NTC thermistor between the SPD
pin and ground and in which case the controller’s own
pre-set temperature characteristics will be used.
In most applications however, it is expected that the
user will wish to set their own temperature response
characteristics. To do this a 10k⍀NTC thermistor can
be employed in conjunction with a pair of resistors to
set such parameters as the speed at 25°C and the slope
of the response up to full speed.
R5 and R6 in both figures are used to set the
temperature response. The ratio between the two
resistors will enable the user to set the speed of the fan
at 25°C. This is influenced by the mechanical response
of the fan and also by the inductance of the stator
windings so the resistor ratio needs to be adjusted by
trial to take this into account.
The ratio of R5 compared to the 10k⍀of the thermistor
will determine the slope. Raising the value of R5 in
relation to the Thermistor will give a steeper slope, for
example say 50% speed at 25°C and full speed at 40°C,
whereas lowering the value will make the slope
shallower, for example 50% speed at 25°C and full
speed at 55°C.
Minimum Speed
One of the main features of the ZXBM2004 is the ability
to set a minimum speed that the fan will run. This will
avoid the fan stopping at low temperatures and also
ensures the fan will always start when cold.
Pin SMIN is used to set the minimum speed and simply
consists of a resistor from the pin to ground. A current
forced from this pin through the resistor will give a volt
drop that represents the voltage on the SPD pin that
will in turn represent the minimum speed.
The best approach to set up a fan for this feature is to
run the fan at the desired minimum speed, measure the
voltage on the SPD pin and set that voltage using the
equation shown in the Pin Description section. It might
be found in practice that the E24 series of resistors
results in too course a change. In this situation the E48
series or 2 resistors in parallel or in series will give
more control over the precise minimum speed.
If the minimum speed feature is not required the pin is
left open circuit.
Speed vs Supply Change Normalisation
With the ZXBM2004, and by the addition of one
resistor, it is possible to set the thermistor network so
as the fan’s speed remains constant when the supply
voltage changes. This is very useful where a fan is to be
specified over a large supply voltage range.
Figure 2 illustrates a circuit where the feature is
included. In this case resistor R7 is added into the
thermistor network between the supply and the SPD
pin.
The value chosen for R7 will be dependant upon the
fan’s characteristics but will be typically around 100k⍀.
The precise value is best determined by trial but it
should be pointed out that in order to keep the same
temperature response characteristics the value of R6
will also need to be increased in compensation as the
two resistors are in effect in parallel.
ZXBM2004
SEMICONDUCTORS
PROVISIONAL ISSUE E - APRIL 2003
9
External Voltage and PWM control
As an alternative to control by a thermistor it is also
possible to control the speed of the fan by a signal from
an external source. This signal may be either a control
voltage or PWM waveform signal.
When a voltage signal is used it will be applied to the
SPD pin and should vary between 1V representing full
speed (100% PWM drive) and 2V representing 0% PWM
drive. In practice, and dependant upon the other
aspects of the motor design, low speed might be
represented by 50% PWM drive. If the Minimum Speed
feature is required then the signal should be applied to
the ZXBM2004 SPD pin via a 2.2k⍀resistor to allow the
internal minimum speed circuit to over-ride the control
voltage.
Where control is required using an externally
generated PWM signal the SPD pin should be left open
circuit and the PWM signal applied to the CPWM pin. The
signal can be a conventional 5V or 3.3V TTL or CMOS
compatible waveform.
ZXBM2004
SEMICONDUCTORS
PROVISIONAL ISSUE E - APRIL 2003
10
Bipolar Types
(NPN) VCEO (V) IC(A) Min HFE @ICVCE(sat) max(mV)
@ IC/IB Package
FCX1053A 75 4.5 300 @ 0.5A 200 @ 1A / 10mA SOT89
FZT851 60 6 100 @ 2A 100 @ 1A / 10mA SOT223
FZT853 100 6 100 @ 2A 175 @ 1A / 100mA SOT223
FZT855 150 4 100 @ 1A 65 @ 0.5A / 50mA SOT223
ZXT13N50DE6 50 4 300 @ 1A 100 @ 1A / 10mA SOT23-6
A Selection of Suitable Transistors and MOSFETs
MOSFET Types
(N-channel) VDS (V) ID(A) IPEAK (A)
(Pulsed) RDS(on) max(mW)
@V
GS
Package
ZXMN3A04DN8130 7.6 25 20 @10V SO8 (DUAL
ZXMN6A09DN812 60 5 17.6 45@10V SO8 (DUAL)
ZXMN6A07F 60 1 4 45 @ 10V SOT23
ZXMN6A11Z 60 3.8 10 140@10V SOT89
ZXMN6A11G 60 3.8 10 140@10V SOT223
ZXMN10A11G 100 1.9 5.9 600@10V SOT223
Note: Dimensions in Inches are Control Dimensions dimensions in millimetres are approximate
ZXBM2004
SEMICONDUCTORS
PROVISIONAL ISSUE E - APRIL 2003
Europe
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Chadderton
Oldham, OL9 8NP
United Kingdom
Telephone (44) 161 622 4444
Fax: (44) 161 622 4446
hq@zetex.com
Zetex GmbH
Streitfeldstraße19
D-81673 München
Germany
Telefon: (49) 89 45 49 49 0
Fax: (49) 89 45 49 49 49
europe.sales@zetex.com
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Hauppauge, NY 11788
USA
Telephone: (1) 631 360 2222
Fax: (1) 631 360 8222
usa.sales@zetex.com
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Hong Kong
Telephone: (852) 26100 611
Fax: (852) 24250 494
asia.sales@zetex.com
These offices are supported by agents and distributors in major countries world-wide.
This publication is issued to provide outline information only which (unless agreed by the Company in writing) may not be used, applied or reproduced
for any purpose or form part of any order or contract or be regarded as a representation relating to the products or services concerned. The Company
reserves the right to alter without notice the specification, design, price or conditions of supply of any product or service.
For the latest product information, log on to www.zetex.com
© Zetex plc 2003
11
PACKAGE OUTLINE SO14N
DIM INCHES MILLIMETRE
MIN. MAX. MIN. MAX.
A 0.053 0.069 1.35 1.75
A1 0.004 0.010 0.10 0.25
D 0.337 0.344 8.55 8.75
H 0.228 0.244 5.80 6.20
E 0.150 0.157 3.80 4.00
L 0.016 0.050 0.40 1.27
e 0.050 BSC 1.27 BSC
b 0.013 0.020 0.33 0.51
c 0.008 0.010 0.19 0.25
θ0°8°0°8°
h 0.010 0.020 0.25 0.50
PACKAGE DIMENSIONS
PACKAGE OUTLINE QSOP16
DIM INCHES MILLIMETRE
MIN. MAX. MIN. MAX.
A 0.053 0.069 1.35 1.75
A1 0.004 0.010 0.10 0.25
A2 0.049 0.059 1.25 1.50
D 0.189 0.197 4.80 5.00
ZD 0.009 Ref 0.23 BSC
E 0.228 0.244 5.79 6.20
E1 0.150 0.157 3.81 3.99
L0.016 0.050 0.41 1.27
e 0.025 BSC 0.64 BSC
b 0.008 0.012 0.20 0.30
c 0.007 0.010 0.18 0.25
θ0°8°0°8°
h 0.010 0.020 0.25 0.50
PACKAGE DIMENSIONS
