ROHM BD9853AFV Technical data

Large Current External FET Controller Type Switching Regulators

Single/Dual-output High-frequency
Step-down Switching Regulator(Controller type)

BD9853AFV

●Description

The BD9853AFV is a 2-ch synchronous DC/DC controller that can operate at a maximum switching frequency of 2MHz,
enabling the use of a smaller external coil than conventional lower-frequency switching regulators. This makes the
BD9853AFV a suitable choice for downsizing applications.

●Features

1) Synchronous Switching Regulator Controller 2channels

2) FET(Pch/Nch) Direct Drive

3) Adjustable Oscillator Frequency with External Resistor (Max. 2MHz)

4) Under Voltage Lockout Function (UVLO)

5) Thermal Shut Down Function (TSD)

6) Short Circuit Protection (SCP)

7) Independent ON/OFF Function in Each Channel with Soft Start Pin

8) SSOP-B16 Package

●Applications
TVSTB, PC, Portable CD・DVD,DVC etc.

●Absolute Maximum Ratings (Ta = 25℃)

Parameter Symbol Limits Unit

Supply Voltage (VCC-GND) Vcc 18 V

VREGA-GND Voltage VREGA 7 V

VCC-VREGB Voltage VREGB 7 V

Power Dissipation Pd 562(*1) mW
Operating Temperature Range Topr -40 to +85 ℃
Junction Temperature Tjmax +150 ℃
Storage Temperature Range Tstg -55 to +150 ℃

* Reduced by 4.49mW for each increase in Ta of 1℃ over 25℃ (When mounted on a board 70×70×1.6tmm grass-epoxy PCB)

●Recommended Operating Conditions

Parameter Symbol

Supply Voltage Vcc 4.5 12 16 V

Oscillator Frequency fosc 100 1000 2000 KHz

SSOPB16

Limits

Min. Typ. Max.

No.09028EAT05

Unit

www.rohm.com

© 2009 ROHM Co., Ltd. All rights reserved.

1/16

2009.05 - Rev.A

BD9853AFV

Technical Note

●Electrical Characteristics (Unless otherwise specified Ta=25℃,Vcc=12V,fosc=1000kHz,STB=3V)

Parameter Symbol

Min. Typ. Max.

Limits

Unit Conditions

【Whole Device】

Standby Current Iccst － 0 5 μASTB=0V
Circuit Current Icc － 3.2 5.2 mA INV1,INV2=2.5V

【Regulator for Driver REGA】

Output Voltage Vrega 4.5 5.0 5.5 V
Output Current Capability Irega － － -100 mA Vrega > 4.5V

【Regulator for Driver REGB】

Output Voltage Vregb VCC-5.5 VCC-5.0 VCC-4.5 V
Output Current Capability Iregb 100 － － mA Vregb < Vcc-4.5V

【Oscillator】

Oscillator Frequency fosc 900 1000 1100 kHz

RRT=8.2kΩ
OUTH=2200pF,OUTL=1000pF

Oscillator Frequency Coefficient1 Dfosc1 -2 0 2 % Vcc=4.5 to 5V

Oscillator Frequency Coefficient2 Dfosc2 -2 0 2 % Vcc=5 to 18V

【Error Amplifier】

Threshold Voltage Vthea 0.79 0.80 0.81 V
Input Bias Current Ibias -230 -115 － nA

Voltage Gain Av 60 80 100 dB DC GAIN
Max. Output Voltage Vfbh Vrega-0.85 － － V
Min. Output Voltage Vfbl － － 0.85 V

Output Sink Current Isink 2 11 - mA INV=2.5V, FB=2.5V

Output Source Current Isource - -15 -2 mA INV=0V, FB=2.5V

【PWM Comparator】

0% Threshold Voltage Vth0 1.4 1.5 1.6 V FB Voltage

100% Threshold Voltage Vth100 2.4 2.5 2.6 V FB Voltage

* This product is not designed for the protection against radioactive rays.

ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM

www.rohm.com

© 2009 ROHM Co., Ltd. All rights reserved.

2/16

2009.05 - Rev.A

BD9853AFV

Technical Note

●Electrical Characteristics (Unless otherwise specified, Ta=25℃,Vcc=12V,fosc=1000kHz,STB=3V)

Parameter Symbol

Min. Typ. Max.

Limits

Unit Conditions

【FET Driver】

On Resistance (OUT1H)

On Resistance (OUT1L)

On Resistance (OUT2H)

On Resistance (OUT2L)

RonP 1.6 3.2 4.8 Ω OUT=Hi
RonN 1.7 3.4 5.1 Ω OUT=Lo
RonP 1.6 3.2 4.8 Ω OUT=Hi
RonN 1.7 3.4 5.1 Ω OUT=Lo
RonP 1.6 3.2 4.5 Ω OUT=Hi
RonN 1.7 3.4 5.1 Ω OUT=Lo
RonP 1.6 3.2 4.8 Ω OUT=Hi

RonN 1.7 3.4 5.1 Ω OUT=Lo
Dead Time(Turn ON) tdtON 30 70 120 ns *OUTH,L H→L,OUTH=2200pF,OUTL=1000pF
Dead Time(Turn OFF) tdtOFF 25 60 115 ns *OUTH,L H→L,OUTH=2200pF,OUTL=1000pF

【Control Block】

Threshold Voltage Vstb 0.6 1.5 2.4 V
Sink Current Istb 6 15 30 μA

【Soft Start Block】

Soft Start Start-yo Voltage Vstasoft 0.2 0.3 0.4 V Output OFF when Vscp/SOFT＜Vstass
Standby Voltage Vstsoft － － 40 mV SCP/SOFT Voltage
Source Current Isosoft -3.2 -2.3 -1.4 μA Vscp/SOFT=0.6V

【Short Circuit Protection (SCP)】

Timer Start Voltage Vtime 0.50 0.56 0.62 V INV Voltage

Threshold Voltage Vthscp 2.2 2.3 2.4 V SCP/SOFT Voltage

Standby Voltage Vstscp 1.21 1.35 1.49 V SCP/SOFT Voltage (When soft start ends)
Source Current Isoscp -3.2 -2.3 -1.4 μA SCP/SOFT=1.8V

【Under Voltage Lockout (UVLO)】

Threshold Voltage Vuvlo 4.0 4.15 4.30 V Vcc sweep down

Hysteresis Voltage DVuvlo 0.05 0.1 0.15 V

* This product is not designed for the protection against radioactive rays.
* Measurement of dead time

Turn ON Turn OFF

OUTH

OUTL

2.5V

tdtON

VCC-2.5V

VCC-2.5V

OUTH

2.5V

OUTL

tdtOFF

www.rohm.com

© 2009 ROHM Co., Ltd. All rights reserved.

3/16

2009.05 - Rev.A

BD9853AFV

●Characteristic Data

100

90

80

70

60

50

ONDUTY[%]

40

30

20

10

0

1.31.41.51.61.71.81.92.02.12.22.32.42.52.6

OUTL

OUTH

FB VOLTAGE:VFB[V]

Fig.1 FB VOLTAGE VS ON DUTY

0

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

-11

-12

-13

-14

FB SOURCE CURRENT[mA]

-15

-16

-17

-18

-19

-20
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4 4.2 4.4

OUTL SINK CURRENT:IOUT[mA]

Fig.4 FB SOURCE CURRENT

1000

950
900
850
800
750
700
650
600
550
500
450
400
350
300
250
200
150
100

50

0

0.00.20.40.60.81.01.21.41.61.82.02.22.42.62.83.03.23.43.63.84.0

Fig.7 OUTL SINK CURRENT

FB VOLTAGE[V]

VCC=12V,18V

VCC=4.5V

(OU TL-GN D) VO LTAGE [V]

180
160
140
120
100

80
60
40
20

0

-20

-40

-60

-80

GAIN[dB]、PHASE[deg]

-100

-120

-140

-160

-180

0.01 0.1 1 10 100 1000 10000 100000

Phase

Gain

FREQUENCY[KHz]

Fig.2 ERROR AMP OPEN LOOP

1000

950
900
850
800
750
700
650
600
550
500
450
400
350
300
250
200
150

OUTH SINK CURRENT:IOUT[mA]

100

50

0

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0

VCC=12V,18V

4

VCC=4.5V

(REGB-OUTH) VOLTAGE[V]

Fig.5 OUTH SINK CURRENT

1000

950
900
850
800
750
700
650
600
550
500
450
400
350
300
250
200
150
100

OUTL SOURCE CURRENT:IOUT[mA]

50

0

0.0 0.2 0.4 0.6 0.8 1. 0 1.2 1.4 1.6 1. 8 2.0 2.2 2.4 2.6 2.8 3. 0 3.2 3.4 3. 6 3.8 4.0

VCC=12V,18V

VCC=4.5V

(REGA-OUTL) VOLTAGE[V]

Fig.8 OUTL SOURCE CURRENT

Technical Note

20
19
18
17
16
15
14
13
12
11
10

9
8
7
6
5

FB SINK CURRENT[mA]

4
3
2
1
0

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4

Fig.3 FB SINK CURRENT

1000

950
900
850
800
750
700
650
600
550
500
450
400
350
300
250
200
150
100

50

OUTH SOURCE CURRENT:IOUT[mA]

0

0.00.20.40.60.81.01.21.41.61.82.02.22.42.62.83.03.23.43.63.84.0

Fig.6 OUTH SOURCE CURRENT

FB VOLTAGE[V]

VCC=12V,18V

VCC=4.5V

(VCC-OUTH) VOLTAGE:[V]

www.rohm.com

© 2009 ROHM Co., Ltd. All rights reserved.

4/16

2009.05 - Rev.A

BD9853AFV

●Block Diagram

VOUT1

VCC

VCC

FB1

REGA

REGB

both channel

ON/OFF

5V

VCC-5V

Technical Note

STB

REGA

VCC

REGB

SCP/SOFT1

VOUT2

SCP/SOFT2

INV1

FB2

INV2

RT

SOFT1

0.8V

(Push-Pull)

SOFT2

0.8V

(Push-Pull)

OSC

Timer
Latch

0.56V

TSD

⊿ ｔ

⊿ ｔ

VREF

REGA

REGA

GND

REGB

GND

REGB

VCC

VCC

OUT1H

OUT1L

OUT2H

OUT2L

GND

VCC

Pch

VOUT1

Nch

VCC

Pch

VOUT2

Nch

Fig. 9

www.rohm.com

© 2009 ROHM Co., Ltd. All rights reserved.

5/16

2009.05 - Rev.A

BD9853AFV

●Pin Configuration

Fig. 10

●Pin Description

Pin Number Pin Name Pin Descriptions

Technical Note

1 VCC Input Supply Voltage

2 OUT1H High Side (Main) FET Driver Output Pin (CH1)

3 OUT1L Low Side (Synchronous) FET Driver Output Pin (CH1)

4 REGA Internal Regulator Output Pin (5V Output, 1uF Ceramic Capacitor necessary)

5 RT Oscillator Frequency Adjustment Pin with external Resistor

6 FB1 Error Amplifier Output Pin (CH1)

7 INV1 Error Amplifer Negative Input Pin (CH1)
8 SCP/SOFT1 Short Circuit Protection・Soft Start Delay Time Setting Pin with External Capacitor (CH1)
9 SCP/SOFT2 Short Circuit Protection・Soft Start Delay Time Setting Pin with External Capacitor (CH2)

10 INV2 Error Amplifer Negative Input Pin (CH2)

11 FB2 Error Amplifier Output Pin (CH2)

12 GND Ground Pin

13 STB ON/OFF Control Pin

14 OUT2L Low Side (Synchronous) FET Driver Output Pin (CH2)

15 OUT2H High Side (Main) FET Driver Output Pin (CH2)

16 REGB Internal Regulator Output Pin (VCC-5V Output, 1uF Ceramic Capacitor necessary)

www.rohm.com

© 2009 ROHM Co., Ltd. All rights reserved.

6/16

2009.05 - Rev.A