BA6868FM-E2 [ROHM]
Disk Drive Motor Controller, 1.8A, PDSO28, ROHS COMPLIANT, HSOP-28;
| 型号： | BA6868FM-E2 |
| 厂家： | 
ROHM |
| 描述： | Disk Drive Motor Controller, 1.8A, PDSO28, ROHS COMPLIANT, HSOP-28 电动机控制 光电二极管 |
| 文件： | 总17页 (文件大小：1111K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
TECHNICAL NOTE
Motor Driver IC Series for Tape Record System
Capstan Motor Driver
for High-speed Forwarding
and Rewinding VTR
BA6878EFV,BA6868FM
●Description
The BA6878EFV and BA6868FM are 3-phase, full-wave motor drivers, each of which is used with three external Hall sensors for rotor
position detection. The BA6878EFV incorporates output transistors with saturation prevention circuits, and is driven by linear voltage and
pseudo-linear currents. BA6868FM also incorporates a torque ripple canceling circuit, and is driven by pseudo-linear and PWM voltage.
Moreover, it can respond to the high-speed operation of the motor and ensures high-precision rotation characteristic performance at low
speed.
●Features
1) 180°, 3-phase full-wave pseudo-linear drive system
2) Built-in output saturation prevention circuits (on high and low sides)
3) Selective forward/reverse rotation
4) Built-in FG and hysteresis amplifiers (BA6878EFV only)
5) Built-in current limit and thermal shut down circuits
6) Direct PWM pseudo-linear drive system (BA6868FM only)
7) Built-in torque ripple canceling circuit (BA6868FM only)
8) Built-in Hall sensor bias power supply (BA6868FM only)
●Applications
Non-portable VTR
●Product line
BA6878EFV
4.5～5.5V
4.5～22V
7.4mA
BA6868FM
4.5～6.0V
4.0～20.5V
11mA
Power supply voltage for control block
Power supply voltage for output block
Vcc circuit current
Max. output current
1500mA
1800mA
Torque reference gain
0.77 A/V
1.07 A/V
Current limit voltage
0.5V
External setting
1.5～Vcc-1.7V
Hall amplifier input range
Output drive system
1.5～Vcc-1.5V
Linear voltage and pseudo-linear current PWM voltage and pseudo-linear current
Output saturation prevention circuit
Torque ripple canceling circuit
Rotation direction change
FG signal amplification circuit
Yes
Yes
Yes
Yes
No
No
Yes
Amp + hysteresis Comparator built-in
Package
HTSSOP-B24
HSOP-M28
Ver.B Oct.2005
●Absolute Maximum Ratings
BA6878EFV
Parameter
Symbol
Vcc
Limit
7
Unit
V
Applied voltage
Applied voltage
VM
23
1.1 *1
V
Power dissipation
Pd
W
Operating temperature range
Storage temperature range
Maximum output current
Junction temperature
Topr
Tstg
-25～+75
-55～+150
1500 *2
+150
℃
℃
mA
℃
Iomax
Tjmax
*1 Reduced by 8.8mW/°C over 25°C, when mounted on a PCB (70 mm x 70 mm x 1.6 mm, glass epoxy).
*2 Must not exceed Pd or ASO.
BA6868FM
Parameter
Applied voltage
Symbol
Vcc
Limit
7
Unit
V
Applied voltage
VM
22
V
Power dissipation
Pd
2.20 *1
-25～+75
-55～+150
1800 *2
+150
W
Operating temperature range
Storage temperature range
Maximum output current
Junction temperature
Topr
Tstg
℃
℃
mA
℃
Iomax
Tjmax
*1 Reduced by 17.6 mW/°C over 25°C, when mounted on a PCB (70 mm x 70 mm x 1.6 mm, glass epoxy).
*2 Must not exceed Pd or ASO.
●Operating Conditions
BA6878EFV
Parameter
Symbol
Vcc
Limit
Unit
V
4.5～5.5
4.5～22.0
Operating power supply voltage range
Operating power supply voltage range
Hall amp in-phase input voltage range
VM
V
1.5～Vcc-1.5
VPD
V
BA6868FM
Parameter
Symbol
Vcc
Limit
Unit
V
4.5～6.0
4.5～20.5
Operating power supply voltage range
Operating power supply voltage range
VM
V
1.5～Vcc-1.7
Hall amp in-phase input voltage range
VPD
V
2/16
●Electrical Characteristics (Unless otherwise specified, Ta=25℃,Vcc=5V,VM=12V)
BA6878EFV
Limit
Typ.
Parameter
Symbol
Unit
Conditions
Min.
Max.
＜CAP Drv＞
Circuit current
Icc
-
7.4
0
11.0
6
mA
mV
Ec = GND, input LLH
Heofs
-6
Hall input conversion offset
Torque reference start voltage
Output idling voltage
Ecst
Ecidle
Gio
2.35
-
2.50
0
2.65
10
V
mV
A/V
V
EC=GND
Torque reference input gain
Forward rotation reference voltage range
Reverse rotation reference voltage range
Torque limit current
0.64
-
0.77
-
0.90
2.2
-
VEDF
VEDR
ITL
2.8
0.89
1.20
-
V
1.00
1.55
1.11
1.90
A
RNF=0.5Ω
High-output voltage
VOH
V
IO=-0.8A
Io=0.8A,
Low-output voltage 1
Low-output voltage 2
VOL
1.10
1.55
2.00
V
RNF=0.5Ω,EC<4.5V
Io=0.8A,
VOL2
Voff
1.05
4.5
1.50
4.7
1.95
4.9
V
V
RNF=0.5Ω,EC=Vcc
Low-side saturation prevention off voltage
＜FG Amp＞
FGin- input current
IFGin-
-21
-43
-65
μA
FG Amp Gain1
FG Amp Gain2
DC bias voltage
GFG1
GFG2
VBFG
26
26
33
33
-
-
dB
dB
V
f=500Hz
f=30kHz
2.4
2.5
2.6
IFG=-0.2mA,
VFGH=Vcc-FGout
IFG=1mA
High FG output voltage
VFGH
VFGL
-
-
0.3
0.2
0.6
0.5
V
V
Low FG output voltage
＜Hys Amp＞
Hysteresis width
Vhys
VhysL
Rhys
32
-
46
0.17
20
60
0.39
25
mV
V
Low hysteresis output voltage
Output pull-up resistance
Ihys=1mA
15
kΩ
3/16
BA6868FM
Limit
Typ.
Parameter
symbol
Icc
Unit
mA
Conditions
Min.
-
Max.
17
＜Overall＞
Circuit current
＜Hall input＞
11
Ec=GND, input LLH
Hall input conversion offset
Hall element power supply voltage
＜Torque reference＞
Heofs
VHp
-10
-
10
mV
V
2.45
2.65
2.85
IH+=9mA
ECofs
-120
-
+120
mV
Torque reference offset voltage
Torque reference input gain
Output idling voltage
Gio
0.95
-
1.07
-
1.18
10
A/V
mV
V
RNF=0.5Ω
ECidle
VECR
ECR bias voltage
2.0
2.2
2.4
＜Torque limit＞
TL-CS offset voltage
TL-CSofs
VRcc
39
56
73
ｍV
＜Ripple canceling＞
Ripple canceling rate
6.3
9.0
11.7
%
Input LLH→LMH
＜Forward/Reverse rotation selection＞
Forward rotation reference voltage range
Reverse rotation reference voltage range
＜Output＞
VEDF
VEDR
-
-
-
2.2
-
V
V
2.8
High-output voltage
VOH
VOL
0.63
0.42
0.90
0.60
1.17
0.78
V
V
Io=-350mA
Low-output voltage
Io=350mA,RNF=0.5Ω
＜Oscillator＞
High OSC voltage
VOSCH
VOSCL
FOSC
1.7
1.0
30
2.1
1.2
50
2.5
1.4
70
V
V
Low OSC voltage
Oscillating frequency
kHz
COSC=1000pF
4/16
●Reference Data
BA6878EFV characteristic data
10
9
8
7
6
5
4
3
2
1
0
1.20
1.00
0.80
0.60
0.40
0.20
0.00
0.0
-0.2
-0.4
-0.6
-0.8
-1.0
-1.2
-1.4
-1.6
-1.8
-2.0
75℃
25℃
75℃
25℃
-25℃
75℃
25℃
-25℃
-25℃
Operating range
(4.5～5.5V)
0.0
1.0
2.0
3.0
4.0
5.0
0
1
2
3
4
5
0.0
0.2
0.4
0.6
0.8
1.0
Vcc [V]
EC [V]
Io [A]
Fig.1 Circuit Current
Fig. 2 Torque Reference Input Gain
Fig. 3 High-Output Voltage (Saturation
Prevention on High Side) vs Current
0.0
3.0
2.5
2.0
1.5
1.0
0.5
0.0
3.0
2.5
-0.1
75℃
-25℃
75℃
25℃
25℃
2.0
25℃
-0.2
-25℃
75℃
1.5
-0.3
-0.4
-0.5
1.0
0.5
0.0
-25℃
0
100
200
300
400
2.5
3.0
3.5
EC [V]
4.0
4.5
0.0
0.2
0.4
0.6
0.8
1.0
IFG [μA]
Fig. 6 High FG Output Voltage vs Current
Io [A]
Fig. 5 Low-Output Voltage 2 vs Current
Fig. 4 Low-side Saturation Prevention vs EC
0.4
40.0
38.0
1.5
75℃
75℃
0.3
1.0
0.5
0.0
-25℃
25℃
-25℃
36.0
25℃
0.2
34.0
25℃
0.1
32.0
-25℃
75℃
30.0
0.0
4.5
4.7
4.9
5.1
5.3
5.5
0
1
2
3
4
5
0
1
2
3
4
5
6
7
8
Vcc [V]
IFG [mA]
Ihys [ mA]
Fig. 8 Low Hysteresis Output Voltage vs Current
Fig. 9 FG Amp Gain 2
Fig. 7 Low FG Output Voltage vs Current
60
50
40
75℃
25℃
30
-25℃
20
10
0
4.5
4.7
4.9
5.1
5.3
5.5
Vcc [V]
Fig. 10 Hys Amp Hysteresis Width
5/16
●Reference Data
BA6868FM characteristic data
4.0
3.0
2.0
1.0
0.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
15
75℃
75℃
25℃
25℃
10
-25℃
25℃
-25℃
-25℃
5
Operating range
（4.5～6.0V)
75℃
0
0
50
100
150
0
1
2
3
4
5
0
1
2
3
4
5
6
IH+ [mA]
EC [V]
Vcc [V]
Fig.11 Circuit Current
Fig.13 Torque Reference Input Gain
Fig.12 Hall Element Power Supply
Voltage vs Current
80
60
40
20
0
80
20
15
10
5
60
40
20
0
-25℃
25℃
75℃
-25℃
75℃
25℃
25℃
75℃
-25℃
0
4.5
5.0
5.5
6.0
4.5
5.0
5.5
6.0
4.5
5.0
5.5
6.0
Vcc [V]
Vcc [V]
Vcc [V]
Fig.16 Ripple Canceling Rate
Fig.14 Torque Reference Offset Voltage
Fig.15 TL-CS Offset Voltage
0.0
1.5
1.0
0.5
0.0
80
70
60
50
40
30
-0.2
-25℃
-0.4
75℃
25℃
-0.6
25℃
75℃
-0.8
-25℃
-1.0
-1.2
-1.4
-1.6
-1.8
-2.0
75℃
25℃
-25℃
0.0
0.3
0.6
0.9
1.2
1.5
1.8
0.0
0.3
0.6
0.9
1.2
1.5
1.8
4.5
5.0
5.5
6.0
Io [A]
Io [A]
Vcc [V]
Fig. 18 Low-side Output Voltage vs Current
Fig. 19 Oscillating Frequency
Fig. 17 High-side Output Voltage vs Current
6/16
●Block Diagram
BA6878EFV
O UTPUT
R NF
A2
A3
0.33～0.5Ω
See P12/16.
VCC
G ND
FＧout
PC I
+
Vcc
1～10μF
See P12/16.
A1
Difference Divider
Matrix
VM
VM
+
Saturation
Vcc
Prevention Circuit
Hall Am p
1～10μF
See P12/16.
T SD
H 2+
H2-
1000～2200pF
See P12/16.
+
HALL
-
10～50kΩ
PCV
-
See P12/16.
+
C SAmp
EC Amp
Vref
0.01～0.022uF
See P12/16.
+
EC
TL
H1+
H 1-
+
HALL
-
rotation
direction
ED/S
H 3+
H 3-
Ｈysout
+
-
HALL
-
+
FG IN
FGin-
10～50kΩ
Vref
FG Am p
Hysteresis Com parator
See P12/16.
0.1～0.22uF
See P12/16.
N.C.
N .C .
N.C.
N.C.
Fig.20
PIN No.
1
Pin name
A3
Function
Motor output pin
Power supply pin
GND pin
2
Vcc
3
GND
FGout
PCI
4
FG amplifier output pin
5
Capacitor connection pin for phase compensation of output saturation prevention circuit for low side
Capacitor connection pin for phase compensation of output saturation prevention circuit for high side
Torque control signal input pin
6
PCV
EC
7
8
ED/S
Hysout
FGin-
N.C
Rotation direction selection pin (L: Forward; H: Reverse)
Hysteresis amplifier output pin
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
FG amplifier input pin
N.C
N.C
N.C
H3-
Hall signal input pin
H3+
H1-
Hall signal input pin
Hall signal input pin
H1+
H2-
Hall signal input pin
Hall signal input pin
H2+
VM
Hall signal input pin
Motor power supply pin
Motor output pin
A1
A2
Motor output pin
RNF
Motor GND pin (resistance connection pin for output current detection)
7/16
Saturation Prevention
for high and low sides
BA6868FM
PCI
H2+
H2-
PCV
0.1～0.22uF
See P.12/16.
0.1～0.22uF
Hall Amp
See P.12/16.
SGND
N.C.
TSD
+
HALL
-
A1A2A3
Oscillation
OSC
RCC
H1+
+
-
1000pF±10%
HALL
HALL
See P.12/16.
Ripple
cancel
H1-
H3+
-
ECR
CNF
+
-
+
ECAmp
H3-
FIN
10～50kΩ
See P.12/16.
0.01～0.022uF
See P.12/16.
rotation
direction
FIN
10～50kΩ
See P.12/16.
Signal Synthesization
Hall Power
supply
MGND
TL
VH+
VCC
Com
+
EC
VM
+
0.33～0.5Ω
See P.12/16.
A3
A2
A1
N.C.
ED/S
1～10μF
See P.12/16.
+
-
CS
A3
A2
A1
CSAmp
1～10μF
See P.12/16.
OUTPUT
RNF
N.C.
Fig.21
PIN No.
Pin name
PCV
SGND
N.C.
OSC
RCC
ECR
CNF
MGND
TL
Function
1
Capacitor connection pin for phase compensation of output saturation prevention circuit for high side
Signal block GND pin
2
3
4
Capacitor connection pin for oscillation circuit
Resistance connection pin for ripple canceling rate adjustment (connected to VCC or GND)
Torque reference input pin
5
6
7
Capacitor connection pin for current feedback phase compensation
Motor GND pin
8
9
Torque limit setting pin
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
EC
Torque control signal input pin
ED/S
CS
Rotation direction setting input pin (L: Forward rotation: H: Reverse rotation)
Output current detection pin
RNF
N.C.
A1
Resistance connection pin for output current detection
Motor output pin
Motor output pin
Motor output pin
A2
A3
N.C.
VM
Motor power supply pin
Vcc
Power supply pin
VH+
H3-
Hall element power supply pin
Hall signal input pin
H3+
H1-
Hall signal input pin
Hall signal input pin
H1+
H2-
Hall signal input pin
Hall signal input pin
H2+
PCI
Hall signal input pin
Capacitor connection pin for phase compensation of output saturation prevention circuit for low side
8/16
●Block Operation
1. BA6878EFV
1-1. Hall amplifier to output
The sine wave signal of the rotor position detection, from the Hall sensor, is input into the Hall amplifier for amplification. The
Matrix synthesizes a sine wave signal (that has a 30° phase delay) to the hall input signal by computing these amplified signals.
Difference Divide outputs a drive basic signal by changing the amplitude of the synthesized signal in proportion to the control
signal. This drive basic signal is amplified by a constant scale factor, and a current is linearly supplied from each output pin.
1-2. EC Amplifier, TL
The output current can be controlled with voltage applied to the EC pin (torque control signal input pin). The EC amplifier
attenuates the voltage differential between the EC pin and Vref pin (with internal reference voltage) at a constant ratio, and
provides it as input voltage to the CS amplifier.
1-3. CS Amplifier, TL
The RNF pin is the GND pin at the motor output block. Connect low resistance (0.5Ω is recommended) between the RNF and
GND pins for output current detection. The voltage generated here is fed back to the input of CS amplifier. The amplitude of the
drive basic signal is changed and the output current is controlled, so that this voltage will be the same as the voltage from the EC
amplifier explained in 1-2. Furthermore, the TL circuit restricts the output current by providing internal reference voltage.
Torque control signal input (EC) and RNF pin voltage have the following relationship:
RNF
V
[V]
Torque limit
EC
[V]
Fig.22
Torque reference start voltage
1-4. Saturation Prevention Circuit
The lowest voltage between the output and GND pins of the low-side output transistor (when on), and the highest voltage
between the VM and output pins of the high-side transistor (when on), are detected so as to prevent the gain from dropping, as a
result of the saturation of the output transistors. The output transistors are controlled to amplify signals at a constant gain. These
transistors are used in the linear mode. For the phase compensation of the feedback loop, in order to detect output voltage,
connect a capacitor between the GND and the PCV and between the GND and PCI pins.
1-5. Rotation Direction Change
A waveform synthesis change is made according to the voltage on the ED/S pin, which alters the relation between the input
signal and output, thus selecting the forward or reverse rotation of the motor.
ED/S pin voltage < 2.2 V: Forward rotation
ED/S pin voltage > 2.8 V: Reverse rotation
1-6. FG Amplifier and Hysteresis Comparator
FG amplifier uses the internal gain setting resistance to amplify input signals at a gain of 33 dB (Typ.). The hysteresis comparator
removes the noise of the linear signal output, of the FG amplifier, and changes the output into rectangular waves.
2. BA6868FM
2-1. Hall amplifier to output
The Hall amplifier receives under differential control. It amplifies sine wave signals, of rotor position detection, from the Hall
sensor. Under signal synthesis control, these amplified signals are calculated, resulting in a sine wave signal with a delay of 30°
to the Hall input signal. Then, a drive basic signal from the synthesized signal, with its amplitude changed in proportion to the
control signal of the CS amplifier, is output. A full-wave rectified waveform is made from the waveforms of respective phases of
the synthesized sine wave signals. The lowest part of the three-phase, full-wave rectified waveform is obtained, and a triangular
waveform that rises and falls alternately (at an angle of 30°) is made as a ripple, canceling the reference waveform. If the output
current is a trapezoid waveform, the triangular waveform (i.e. the ripple-canceling reference waveform) will be superimposed on
the trapezoid waveform. This is to prevent a delicate rotation fluctuation caused by spaces in the magnetic field, that are
generated by the 3-phase coils. The drive basic signal, that is pulse-wave modulated by the PWM signal for output current
control, is amplified and output at constant gain. For this reason, the output voltage can supply phase current linearly in PWM
drive control.
9/16
2-2. EC Amplifier
The output current can be controlled with a voltage applied to the EC pin (torque control signal input pin). The EC amplifier
attenuates the voltage differential of the ECR pin at a constant ratio, and inputs the attenuated voltage to the CS amplifier. The
signal of the ripple canceling reference waveform, attenuated at a constant ratio by a resistor connected between the RCC and
GND pin, is superimposed on the input voltage
2-3. CS Amplifier, Comparators
The RNF pin is the GND pin at the output stage. A low resistor (with a recommended resistance of 0.33 Ω to 0.5 Ω) is connected
between the RNF and GND pins for output current detection. The voltage generated here is fed back to the input of the CS
amplifier, and a signal that changes the amplitude of the drive basic signal is given to the synthesis circuit. This is so that the
generated voltage will become the same as that of the EC amplifier, as explained in 2-2. A duty control signal is output for
PWM-on. Duty control is done by comparing the signal with the triangular waveform input for the PWM comparator.
An amplitude control signal and a duty control signal are mixed to control the output current. The output current can be restricted
by providing constant voltage to the TL pin. In order to perform the phase compensation of the feedback loop for current detection,
a capacitor is connected between the CNF and GND pins to prevent oscillation.
Torque reference input (EC) and RNF pin voltage have the following relationship:
Torque reference offset
VRNF
[V]
(MAX±120mV)
ECR
EC [V]
Fig.23
2-4. Torque Limit
The output current can be restricted by the voltage applied to the TL pin. Connect a resistance of approximately 0.33 Ω to 0.5 Ω
between the RNF and MGND pins, and as a result, current detection is performed. As long as the voltage applied to the TL pin
is VTL, the maximum output current Iomax is calculated as follows:
VTL-(TL-RNFofs)
Iomax＝
RNF
TL-RNFofs is the offset between the TL and RNF pins. RNF is the resistance for current detection between RNF and MGND pins
2-5. Saturation Prevention Circuit on High and Low Sides
The lowest voltage between the output and GND pins of the low-side output transistor (when on), and the highest voltage
between the VM and output pins of the high-side transistor (when on), are detected so as to prevent the gain from dropping as a
result of the saturation of the output transistors. The output transistors are controlled to amplify signals at constant gain. The
output transistors are used in the linear mode, which ensures good control performance in a wide current range between small
and large currents, and provides good rotation performance even if the motor is overloaded. For the phase compensation of the
feedback loop, in order to detect output voltage, connect a capacitor between the GND and the PCV and between the GND and
PCI pins.
2-6. Rotation Direction Change
A waveform synthesis change is made according to the voltage on the ED/S pin, which alters the relation between the input
signal and output, thus selecting the forward or reverse rotation of the motor.
ED/S pin voltage < 2.2 V: Forward rotation
ED/S pin voltage > 2.8 V: Reverse rotation
2-7. Oscillation Circuit
A PWM comparator input signal is generated by connecting a capacitor to the OSC pin, charging it with a constant current, and
discharging it at constant amplitude.
2-8. Hall Power Supply
The hall sensor is supplied with 2.65 V (Typ.).
10/16
●I/O Truth Table
BA6878EFV
ED/S = Low (Forward rotation)
ED/S = High (Reverse rotation)
H1+
M
H
H
H
H
H
M
L
H2+
H
H
M
L
H3+
L
A1
H
M
L
A2
L
A3
H
H
H
H
H
M
L
H1+
M
H
H
H
H
H
M
L
H2+
L
H3+
H
H
M
L
A1
H
H
H
H
H
M
L
A2
L
A3
H
M
L
L
L
L
L
L
L
L
L
L
L
M
H
H
H
H
H
M
L
L
M
H
H
H
H
H
M
L
L
L
M
H
H
H
H
H
M
L
L
M
H
H
H
H
H
M
L
L
L
L
L
L
L
L
L
L
L
L
M
H
H
H
H
L
L
L
M
H
H
H
H
L
M
H
H
H
L
L
M
H
H
H
L
L
L
L
L
L
L
L
L
L
L
M
L
M
L
BA6868FM
ED/S = Low (Forward rotation)
ED/S = High (Reverse rotation)
Hall input
Output
Hall input
Output
H1+ H2+ H3+
A1
L
A2
H
L
A3
H
H
H
L
H1+ H2+ H3+
A1
H
H
L
A2
L
A3
1
2
3
4
5
6
L
L
H
M
L
M
H
H
M
L
1
2
3
4
5
6
L
L
H
M
L
M
H
H
M
L
L
L
L
H
H
H
L
M
H
H
M
H
H
H
H
L
M
H
H
M
L
L
L
L
L
H
H
H
M
H
H
H
L
M
H
L
L
L
L
H
L
11/16
●Selecting Application Components
1) Hall bias resistance <BA6878EFV, BA6868FM>
The Hall sensor allows both serial and parallel connections. Adjust the bias resistance so that the amplitude of the Hall signal will be
approximately 100 mVp-p and within the permissible Hall input voltage range. The BA6868FM is provided with the Hall power supply
pin.
Vcc or VH
Vcc or VH
H1
H2
H3
H1
H2
H3
Parallel connection
Serial connection
Fig.24
2) Connection Capacity of PCI and PCV Pins <BA6878EFV>
Capacitors connected to the PCI and PCV pins are for the saturation prevention circuits on the high and low sides, and are for phase
compensation for the current feedback loop. If the capacitance is too high, poor responsiveness will result. If the capacitance is too low,
the output waveform will be sensitive to oscillation. Determine the capacitance based on the servo constant.
3) Connection capacity for PCI pin, PCV pin, and CNF pin. <BA6868FM>
Capacitors connected to the PCI, PCV, and CNF pins are for the saturation prevention circuits on the high and low sides, and are for
phase compensation for the current feedback loop. If the capacitance is too high, poor responsiveness will result. If the capacitance is
too low, the output waveform will be sensitive to oscillation. Determine the capacitance based on the servo constant.
A capacitance of approximately 0.1 µF to 0.22 µF is suitable for the PCI pin, while a capacitance of approximately 0.1 µF to 0.22 µF is
suitable for the PCV pin, and 0.01 µF to 0.022 µF for the CNF pin.
4) OSC Oscillation Circuit <BA6868FM>
By charging and discharging the capacitor connected to the OSC pin, a triangular wave will be formed at PWM frequency. If the PWM
frequency is too low, the output current will cease. If the PWM frequency is too high, the output waveform cannot respond to the PWM
frequency. Set the optimum PWM frequency. The optimum frequency is approximately 50 kHz, with a capacitance of 1000 pF ± 10%
connected to the OSC pin.
VOSCH：2.1V(Typ.)
OSC voltage
VOSCL：1.2V(Typ.)
Charging Discharging
Fig.25
5) Forward/Reverse Rotation Selection <BA6878EFV, BA6868FM>
A rise of the motor output voltage of the IC is seen when changing the rotation direction of the IC in operation. This is due to the
generation of BEMF voltage, generated from the coil. If this rise exceeds the maximum rating, the IC may be damaged. Therefore, set
VM voltage so that the output will not exceed maximum ratings or ASO at the time of changing the rotation direction. Furthermore, in
order to suppress the rise of the output voltage, connect a capacitor (approximately 1 µF to 10 µF) between VM and GND pins, and as
close as possible to the IC.
6) RNF pin <BA6878EFV, BA6868FM>
In order to detect the output current, connect a small resistance (0.33 Ω to 0.5 Ω) between the RNF and GND pins. A large current flows
to this resistance. Therefore, pay careful attention to the current capacity.
7) VCC and VM Pins <BA6878EFV, BA6868FM>
Select a capacitance value that can sufficiently suppress high-frequency noise.
The optimum capacitance is 1 µF to 10 µF.
12/16
●I/O Equivalent Circuit Diagrams
1) Motor Output Block <BA6878EFV>
＜BA6878EFV＞
＜BA6868FM＞
VM
VM
A1
A2
A3
A1
A2
A3
RNF
RNF
Fig.26
Fig.27
2) Rotation Direction Selection Pin
3) Hall Power Supply <BA6868FM>
Vcc
Vcc
ED/S
VH+
Fig.29
Fig.28
4) Torque Reference
＜BA6878EFV＞
＜BA6868FM＞
Vcc
Vcc
Vcc
EC
ECR
EC
Fig.31
Fig.30
5) Hall input
6) Torque Limit＜BA6868FM＞
Hn+
Hn-
CS
MGND
TL
Fig.33
Fig.32
7) FG_Amp, Hys_Amp Input Pin
＜BA6878EFV＞
Vcc
FGin-
Vcc
Vcc
Hysout
FGout
Fig.34
Fig.35
13/16
●Operation Notes
1. Absolute maximum ratings
An excess in the absolute maximum ratings, such as supply voltage, temperature range of operating conditions, etc., can break down the
devices, thus making impossible to identify breaking mode, such as a short circuit or an open circuit. If any over rated values will expect to
exceed the absolute maximum ratings, consider adding circuit protection devices, such as fuses.
2. Connecting the power supply connector backward
Connecting of the power supply in reverse polarity can damage IC. Take precautions when connecting the power supply lines. An external
direction diode can be added.
3. Power supply lines
Design PCB layout pattern to provide low impedance GND and supply lines. To obtain a low noise ground and supply line, separate the
ground section and supply lines of the digital and analog blocks. Furthermore, for all power supply terminals to ICs, connect a capacitor
between the power supply and the GND terminal. When applying electrolytic capacitors in the circuit, note that capacitance characteristic
values are reduced at low temperatures.
4. GND voltage
The potential of GND pin must be minimum potential in all operating conditions.
5. Thermal design
Use a thermal design that allows for a sufficient margin in light of the power dissipation (Pd) in actual operating conditions.
6. Inter-pin shorts and mounting errors
Use caution when positioning the IC for mounting on printed circuit boards. The IC may be damaged if there is any connection error or if
pins are shorted together.
7. Actions in strong electromagnetic field
Use caution when using the IC in the presence of a strong electromagnetic field as doing so may cause the IC to malfunction.
8. ASO
When using the IC, set the output transistor so that it does not exceed absolute maximum ratings or ASO.
9. Thermal shutdown circuit
The IC incorporates a built-in thermal shutdown circuit (TSD circuit). The thermal shutdown circuit (TSD circuit) is designed only to shut the
IC off to prevent thermal runaway. It is not designed to protect the IC or guarantee its operation. Do not continue to use the IC after
operating this circuit or use the IC in an environment where the operation of this circuit is assumed.
TSD on temperature [°C] (typ.)
Hysteresis temperature [°C] (typ.)
BA6878EFV
BA6868FM
175
175
15
175
10. Testing on application boards
When testing the IC on an application board, connecting a capacitor to a pin with low impedance subjects the IC to stress. Always
discharge capacitors after each process or step. Always turn the IC's power supply off before connecting it to or removing it from a jig or
fixture during the inspection process. Ground the IC during assembly steps as an antistatic measure. Use similar precaution when
transporting or storing the IC.
11. Regarding input pin of the IC
This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated.
P-N junctions are formed at the intersection of these P layers with the N layers of other elements, creating a parasitic diode or transistor.
For example, the relation between each potential is as follows:
When GND > Pin A and GND > Pin B, the P-N junction operates as a parasitic diode.
When GND > Pin B, the P-N junction operates as a parasitic transistor.
Parasitic diodes can occur inevitable in the structure of the IC. The operation of parasitic diodes can result in mutual interference among
circuits, operational faults, or physical damage. Accordingly, methods by which parasitic diodes operate, such as applying a voltage that is
lower than the GND (P substrate) voltage to an input pin, should not be used.
Resistor
Transistor (NPN)
B
Pin A
Pin B
Pin B
C
E
Pin A
B
C
E
N
N
N
P+
P+
P+
P+
N
P
P
Parasitic
element
N
N
Parasitic
element
P substrate
P substrate
GND
GND
GND
GND
Parasitic element
Parasitic element
Fig. 36 Example of IC structure
Other adjacent elements
12. Ground Wiring Pattern
When using both small signal and large current GND patterns, it is recommended to isolate the two ground patterns, placing a single
ground point at the ground potential of application so that the pattern wiring resistance and voltage variations caused by large currents do
not cause variations in the small signal ground voltage. Be careful not to change the GND wiring pattern of any external components, either.
14/16
●Power Dissipation Reduction
The power dissipation of the IC shows the power consumption of the IC when the ambient temperature (Ta=25°C) is at room temperature.
The IC will generate heat when the IC consumes power, and the temperature of the IC chip will be higher than the ambient temperature.
The power consumption of the IC is limited. The power dissipation is determined by the thermal resistance (heat dissipation performance)
of the package at the permissible temperature (i.e., absolute maximum rating of the junction temperature) of the IC chip in the package.
Heat generated as a result of the power consumption of the IC is dissipated from the mold resin or lead frame of the package. A
parameter that obstruct the thermal dissipation is called thermal resistance and expressed by θj-a [°C/W]. From this thermal resistance,
the IC temperature in the package can be estimated. Fig. 36 shows a model of thermal resistance in the package. The thermal resistance
θj-a, ambient temperature Ta, chip temperature Tj, and power consumption P are obtained from the following formula:
θja ＝ (Tj－Ta) / Pd
[℃/W]
・・・・・ (Ⅰ)
The heat derating curve shows the permissible power consumption of the IC at ambient temperature. The possible power consumption of
the IC decreases with an increase in ambient temperature. This slope is determined by the thermal resistance θja.
The thermal resistance θja is dependent upon various conditions, such as the chip size, power consumption, package ambient
temperature, mounting conditions, and wind velocity. The derating curve shows reference values measured under specified conditions.
Fig. 37 shows the derating curves of the BA6878EFV and BA6868FM. If the BA6878EFV is used at an ambient temperature (Ta) of 25°C
or higher, the power will be reduced at the rate of 8.8 mW/°C. If the BA6868FM is used at an ambient temperature (Ta) of 25°C or higher,
the power will be reduced at the rate of 17.6 mW/°C, on the condition that the IC is mounted on the FR4 glass epoxy board of 70 mm x 70
mm x 1.6 mm in size (with a maximum cupper foil area of 3%).
θja = (Tj-Ta) / P [℃/W]
Ambient temperature Ta [°C]
Chip surface temperature Tj [°C]
Power consumption P [W]
Fig. 37 Thermal Resistance
BA6878EFV
BA6868FM
Pd(W)
1.5
Pd(W)
2.5
1.25
1.1
2.2
2.0
1.0
1.5
1.0
0.75
0.5
0.25
0.5
0
0
25
50
75
100
125
150 Ta(℃)
25
50
75
100
125
150 Ta(℃)
*Reduced by 8.8 mW/°C over 25°C, when mounted on
a glass epoxy board (70 mm x 70 mm x 1.6 mm)
*Reduced by 17.6mW/°C over 25°C, when mounted
on a glass epoxy board (70 mm x 70 mm x 1.6 mm)
Fig.38 Heat Derating Curve
15/16
●Selecting a Model Name When Ordering
Specify the model number when placing your order. Make sure that the combination of each item is correct, and left justify the items with
no space between adjacent items.
―
B
A
6
8
7
8
E
F
V
E
2
Package type
・EFV :HTSSOP-B24
ROHM model name
・BA6878EFV
E1 Reel-wound embossed taping
with pin 1 on the extraction side
E2 Reel-wound embossed taping
with pin 1 on the opposite side
of the extraction side.
・FM : HSOP-M28
・BA6868FM
HTSSOP-B24
<Dimension>
<Tape and Reel information>
Embossed carrier tape
Tape
Quantity
2000pcs
E2
7.8 0.1
+6
4
−4
Direction
of feed
24
13
(The direction is the 1pin of product is at the upper left when you hold
reel on the left hand and you pull out the tape on the right hand)
+0.05
−0.03
1
12
0.17
0.08
0.325
S
0.65
+0.05
0.2
−0.04
M
0.08
Direction of feed
1pin
Reel
（Unit:mm)
※When you order , please order in times the amount of package quantity.
HSOP-M28
<Dimension>
<Tape and Reel information>
Tape
Embossed carrier tape
Quantity
1500pcs
18.5 0.2
28
15
E2
Direction
of feed
(The direction is the 1pin of product is at the upper left when you hold
reel on the left hand and you pull out the tape on the right hand)
1
14
0.25 0.1
5.15 0.1
0.8
0.35 0.1
0.1 S
M
0.08
16.0 0.2
Direction of feed
1Pin
Reel
(Unit:mm)
※When you order , please order in times the amount of package quantity.
Catalog No.05T347Be '05.10 ROHM C 1000 TSU
Appendix
Notes
No technical content pages of this document may be reproduced in any form or transmitted by any
means without prior permission of ROHM CO.,LTD.
The contents described herein are subject to change without notice. The specifications for the
product described in this document are for reference only. Upon actual use, therefore, please request
that specifications to be separately delivered.
Application circuit diagrams and circuit constants contained herein are shown as examples of standard
use and operation. Please pay careful attention to the peripheral conditions when designing circuits
and deciding upon circuit constants in the set.
Any data, including, but not limited to application circuit diagrams information, described herein
are intended only as illustrations of such devices and not as the specifications for such devices. ROHM
CO.,LTD. disclaims any warranty that any use of such devices shall be free from infringement of any
third party's intellectual property rights or other proprietary rights, and further, assumes no liability of
whatsoever nature in the event of any such infringement, or arising from or connected with or related
to the use of such devices.
Upon the sale of any such devices, other than for buyer's right to use such devices itself, resell or
otherwise dispose of the same, no express or implied right or license to practice or commercially
exploit any intellectual property rights or other proprietary rights owned or controlled by
ROHM CO., LTD. is granted to any such buyer.
Products listed in this document are no antiradiation design.
The products listed in this document are designed to be used with ordinary electronic equipment or devices
(such as audio visual equipment, office-automation equipment, communications devices, electrical
appliances and electronic toys).
Should you intend to use these products with equipment or devices which require an extremely high level
of reliability and the malfunction of which would directly endanger human life (such as medical
instruments, transportation equipment, aerospace machinery, nuclear-reactor controllers, fuel controllers
and other safety devices), please be sure to consult with our sales representative in advance.
It is our top priority to supply products with the utmost quality and reliability. However, there is always a chance
of failure due to unexpected factors. Therefore, please take into account the derating characteristics and allow
for sufficient safety features, such as extra margin, anti-flammability, and fail-safe measures when designing in
order to prevent possible accidents that may result in bodily harm or fire caused by component failure. ROHM
cannot be held responsible for any damages arising from the use of the products under conditions out of the
range of the specifications or due to non-compliance with the NOTES specified in this catalog.
Thank you for your accessing to ROHM product informations.
More detail product informations and catalogs are available, please contact your nearest sales office.
THE AMERICAS / EUROPE / ASIA / JAPAN
ROHM Customer Support System
Contact us : webmaster@ rohm.co.jp
www.rohm.com
TEL : +81-75-311-2121
FAX : +81-75-315-0172
Copyright © 2008 ROHM CO.,LTD.
21 Saiin Mizosaki-cho, Ukyo-ku, Kyoto 615-8585, Japan
Appendix1-Rev2.0
相关型号：
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