ROHM BD6721FS Technical data

t

Datashee

DC Brushless Fan Motor Drivers

Multifunction Single-phase Full-wave
Fan Motor Driver

BD6721FS

●General description

BD6721FS is a 1chip driver that composes H-bridge of
power DMOS FET.
Moreover, because the level amplifier is installed, the
temperature control by the thermistor is also easy.

●Features

 Driver including power DMOS FET
 Speed controllable by DC / direct PWM input
 PWM soft switching
 Quick start
 Current limit
 Lock protection and automatic restart
 Rotation speed pulse signal (FG) output
 Lock alarm signal (AL) output

●Application

 Fan motors for general consumer equipment of desktop PC, and Projector, etc.

●Absolute maximum ratings

Parameter Symbol Limit Unit
Supply voltage Vcc 20 V
Power dissipation Pd 812.5
Operating temperature range Topr –40 to +100 °C
Storage temperature range Tstg –55 to +150 °C
Output voltage Vo 20 V
Output current Io 1.0
Rotation speed pulse signal (FG) output voltage Vfg 20 V
Rotation speed pulse signal (FG) output current Ifg 10 mA
Lock alarm signal (AL) output voltage Val 20 V
Lock alarm signal (AL) output current Ial 10 mA
Reference voltage (REF) output current Iref 8 mA
Junction temperature Tj 150 °C

*1 Reduce by 6.5mW/°C over Ta=25°C. (On 70.0mm×70.0mm×1.6mm glass epoxy board)
*2 This value is not to exceed Pd.

●Recommended operating conditions

Parameter Symbol Limit Unit
Operating supply voltage range Vcc 4.5 to 17.0 V
Operating input voltage range
(H+, H–, TH, MIN, LAIN) (more than Vcc=9V)
Operating input voltage range
(H+, H–, TH, MIN, LAIN) (less than Vcc=9V)

●Package W (Typ.) x D (Typ.) x H (Max.)
SSOP-A16 6.60mm x 6.20mm x 1.71mm

*1

mW

*2

A

0 to 7 V

Vin

0 to Vcc–2 V

SSOP-A16

○Product structure：Silicon monolithic integrated circuit ○This product is not designed protection against radioactive rays
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Datasheet

BD6721FS

●Pin configuration

GND

OSC

1

2

LAOUT

LAIN

MIN

OUT1

RNF

TH

3

4

5

6

7

8

Fig.1 Pin configuration

●Block diagram

●I/O truth table

Hall input Driver output

H+ H– OUT1 OUT2 FG

H L L H Hi-Z

L H H L L

H; High, L; Low, Hi-Z; High impedance
FG output is open-drain type.

Motor state AL

Rotating L

Locking Hi-Z

L; Low, Hi-Z; High impedance
AL output is open-drain type.

(TOP VIEW)

Datasheet

●Pin description

P/No. T/Name Function

1 GND Ground terminal (signal ground)

16

15

AL

FG

2 OSC
3 LAOUT Level amplifier output terminal

Oscillating capacitor connecting
terminal

4 LAIN Level amplifier input terminal

REF

14

5 TH Output duty controllable input terminal
6 MIN Minimum output duty setting terminal

13

12

11

H–

H+

Vcc

7 OUT1 Motor output terminal 1
8 RNF

Output current detecting resistor
connecting terminal (motor ground)

9 OUT2 Motor output terminal 2

10 CS Output current detection terminal

CS

10

9

OUT2

11 Vcc Power supply terminal
12 H+ Hall + input terminal
13 H– Hall – input terminal
14 REF Reference voltage output terminal
15 FG Speed pulse signal output terminal
16 AL Lock alarm signal output terminal

Vcl

OUT2

AL

FG

REF

H–

H+

Vcc

CS

16

15

14

13

12

11

10

9

GND

1

OSC

2

LA
OUT

3

TSD

OSC

LA
IN

4

LEVEL

AMP

5

TH

MIN

6

QUICK
START

OUT1

7

RNF

8

PWM
COMP

PWM

COMP

PWM SOFT

SWITCHING

CONTROL

LOGIC

PRE-

DRIVER

SIGNAL
OUTPUT

SIGNAL
OUTPUT

REF

HALL
AMP

HALL
COMP

LOCK

PROTECT

CURRENT
LIMIT COMP

Fig.2 Block diagram

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Datasheet

BD6721FS

●Electrical characteristics(Unless otherwise specified Ta=25°C, Vcc=12V)

Parameter Symbol

Circuit current Icc 4 7 10 mA Fig.3
Hall input hysteresis voltage Vhys ±5 ±10 ±15 mV Fig.4

Output voltage Vo - 0.6 0.9 V
Lock detection ON time Ton 0.3 0.5 0.7 s Fig.9

Lock detection OFF time Toff 3.0 5.0 7.0 s Fig.10
FG output low voltage Vfgl - 0.15 0.30 V Ifg=5mA Fig.11, 12
FG output leak current Ifgl - - 10 µA Vfg=17V Fig.13
AL output low voltage Vall - 0.15 0.30 V Ial=5mA Fig.11, 12
AL output leak current Iall - - 10 µA Val=17V Fig.13
OSC high voltage Vosch 2.3 2.5 2.7 V Fig.14
OSC low voltage Voscl 0.8 1.0 1.2 V Fig.14
OSC charge current Icosc –50 –32 –26 µA Fig.15
OSC discharge current Idosc 26 32 50 µA Fig.15
Level amplifier gain Gla 50 - - dB Fig.16, 17
Level amplifier output high voltage Vlaoh - 1.6 2.0 V For Vcc voltage Fig.18
Level amplifier output low voltage Vlaol - 0.2 0.3 V Fig.19

Output ON duty 1 Poh1 85 90 95 %

Output ON duty 2 Poh2 45 50 55 %

Output ON duty 3 Poh3 5 10 15 %
Reference voltage Vref 2.8 3.0 3.2 V Iref=–2mA Fig.20, 21

Current limit setting voltage Vcl 290 310 330 mV Fig.22
TH input bias current Ith - - –0.2 µA Vth=0V Fig.23
MIN input bias current Imin - - –0.2 µA Vmin=0V Fig.24

About a current item, define the inflow current to IC as a positive notation, and the outflow current from IC as a negative notation.

Limit

Min. Typ. Max.

Unit Conditions

Io=±300mA,
High and low side total

Vth=Vref x 0.383
Output 1kΩ, OSC=470pF
Vth=Vref x 0.583
Output 1kΩ, OSC=470pF
Vth=Vref x 0.783
Output 1kΩ, OSC=470pF

Datasheet

Ref.
data

Fig.5 to 8

-

-

-

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Datasheet

BD6721FS

–

–

–

–

●Typical performance curves(Reference data)

10

8

6

4

Circuit current: Icc[mA]

2

Operating range

0

0 5 10 15 20

Supply voltage: Vcc[V]

Fig.3 Circuit current

0.0

-0.2

-0.4

-0.6

Output high voltage: Voh[V]

-0.8

-1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Output source current: Io[A]

Fig.5 Output high voltage (Vcc=12V)

25°C

100°C

40°C

40°C

25°C

100°C

20

10

0

Operating range

-10

Hall input hysteresis voltage: Vhys[mV]

-20
0 5 10 15 20

Supply voltage: Vcc[V]

Fig.4 Hall input hysteresis voltage

0.0

-0.2

-0.4

-0.6

Output high voltage: Voh[V]

-0.8

-1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Output source current: Io[A]

Fig.6 Output high voltage (Ta=25°C)

Datasheet

100°C

25°C

40°C

40°C

25°C

100°C

17V

12V

5V

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Datasheet

BD6721FS

–

–

–

●Typical performance curves(Reference data)

1.0

0.8

0.6

0.4

Output low voltage: Vol[V]

0.2

0.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Output sink current: Io[A]

Fig.7 Output low voltage (Vcc=12V)

0.7

0.6

0.5

0.4

Lock detection ON time: Ton[s]

Operating range

0.3
0 5 10 15 20

Supply voltage: Vcc[V]

Fig.9 Lock detection ON time

100°C

25°C

40°C

100°C

40°C

25°C

1.0

0.8

0.6

0.4

Output low voltage: Vol[V]

0.2

0.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Output sink current: Io[A]

Fig.8 Output low voltage (Ta=25°C)

7.0

6.0

5.0

4.0

Lock detection OFF time: Toff[s]

Operating range

3.0
0 5 10 15 20

Supply voltage: Vcc[V]

Fig.10 Lock detection OFF time

Datasheet

5V

12V

17V

100°C

40°C

25°C

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© 2012 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001

5/13

TSZ02201-0H1H0B100170-1-2

28.JUL.2012 Rev.002