ROHM BD9850FVM Technical data

TECHNICAL NOTE

Large Current External FET Controller Type Switching Regulators

Single-output High-frequency Step-down Switching Regulator

BD9850FVM

(Controller type)

Dual-output Step-up, Negative, Step-down

High temperature

operating

Now available

ESD

Resistance

Now available

Switching Regulator

(Controller type)

BD9851EFV

Description

The BD9850FVM is a 1-channel DC/DC step-down switching regulator controller, while the BD9851EFV is a 2-channel DC/DC

step-down switching regulator controller. The BD9850FVM is adaptable for a maximum switching frequency of 2 MHz and the

BD9851EFV for that of 3 MHz. Both provide space saving in all applications.

Features

1) Adaptable for 2-MHz switching frequency (externally variable) (BD9850FVM)

Adaptable for 3-MHz switching frequency (externally variable) (BD9851EFV)

2) FET direct drive

3) High-accuracy reference voltage (Accuracy: ±1%)

4) Built-in Under Voltage Lock Out circuit (UVLO)

5) Built-in Thermal Shutdown circuit (TSD)

6) The BD9851EFV provides two channels:

Channel 1 available for selection of step-down/step-up switching

Channel 2 available for selection of step-down/inverting switching.

7) Compact MSOP8 package (BD9850FVM) / HTSSOP-B20 package (BD9851EFV)

Applications

TFT panel, TA/ Router, digital consumer electronics, PC, and portable CD/DVD/DVC

Product lineup

BD9850FVM Input range Oscillation frequency range External synchronization Standby function Operating temperature Package

4V to 9V

100kHz to 2MHz

Not provided Not provided –40˚C to 85˚C

MSOP8

ROHM CO., LTD .

BD9851EFV

4V to 18V

10kHz to 3MHz

Not provided

Provided

–40˚C to 85˚C

HTSSOP-B20

Sep. 2008

Absolute maximum ratings (Ta=25˚C)

BD9850FVM

Item

Power supply voltage

Storage temperature

Operating temperature

Power dissipation

Maximum junction temperature

Reduce by 4.7 mW/ºC over 25ºC (When mounted on PCB of 70mm×70mm×1.6mm)

*

Symbol Rating Unit

Vcc

Tst g

Topr

Pd

Tjmax

10

–55 to +150

–40 to +85

*

587

+150

BD9851EFV

Item

Power supply voltage

(Between

Vcc and GND)

Between VREF and GND

Between OUT1 and PVcc1 Between OUT2 and PVcc2

Between OUT1, OUT2 and PGND

Power dissipation

Operating temperature

Maximum junction temperature

Storage temperature

Symbol Rating Unit

Vcc

REF

V

Vouth

Voutl

Pd

Topr

Tjmax

Tst g

20

7

20

(*)

1000

–40 to +85

+150

–55 to +150

(*)Reduce by 8.0 mW/ºC over 25ºC (When mounted on PCB of 70mm×70mm×1.6mm)

V

ºC

mW

ºC

V

mW

ºC

Recommended operating range

BD9850FVM

Item

Power supply voltage

Oscillation frequency

Operating temperature

BD9851EFV

Item

Power supply voltage

Oscillation frequency

Timing resistor

Timing capacitor

Symbol

Vcc

fosc

Topr

Symbol

Vcc

fosc

RT

R

CCT

4

100

–40

4

10

3.3

33

Limits

Typ. max.min.

7

–

Limits

Typ. max.min.

12

300

–

9

2000

+85

18

3000

47

10000

Unit

V

kHz

ºC

Unit

V

kHz

kΩ

pF

2/16

BD9850FVM

Electrical characteristics (Unless otherwise specied, Ta=25˚C, Vcc=7V, fosc=600kHz)

Item Symbol

Limits

Typ. max.min.

[Oscillator block]

Oscillation frequency

Frequency regulation

Oscillator amplitude voltage

fosc

FDV

Vpptr

510

–5

–

600

0

0.5

690

5

–

[Soft start /SW block]

CTL /SS pin sink current

CTL /SS pin clamp voltage

CTL threshold voltage

ISS

VSS

VCTLTH

–1.90

2.2

1.2

–1.00

2.4

1.3

1.00

2.6

1.4

[PWM comparator block]

Unit

kHz

%

V

μA

V

Conditions

RT = 24kΩ

R

Vcc = 4V to 9V

*

VCTL/SS = 1.5V

0% threshold voltage

100% threshold voltage

[Error Amp block]

Threshold voltage

Frequency bandwidth

Voltage gain

Input bias current

Maximum output voltage

Minimum output voltage

Output source current

Output sink current

REF block]

[V

REF output voltage

V

REF load regulation

F

REF current capacitance

V

[Total device]

Standby current

Average supply current

[Output block]

D0

D100

V

IN

BW

Av

IIB

VCH

VCL

IOl

IOO

REF

V

ΔVREFl0

IVREF

ICCS

ICCA

1.5

2.0

0.98

1.5

–

–150

2.3

–

–3.1

12

2.475

–

–45

420

3.4

1.6

2.1

1.00

3.0

70

–70

2.4

0.03

–1.6

50

2.500

–

–16

610

5.0

1.7

2.2

1.02

–

2.6

0.20

–1.0

125

2.525

10

–1

960

7.8

V

MHz

dB

hA

V

mA

V

mV

mA

μA

mA

fosc = 600kHz

AV = 0dB

*

V

FB = 1.0V

V

I

VREF = 0mA

VREF = 0mA to –1mA

I

At no load

ON resistance

Output transient time

[Under voltage lockout block]

Threshold voltage

Hysteresis width

Design guarantee

*

Not designed to be radiation-resistant.

*

R

ON

Tr/ Tf

VUT

VUThy

0.9

–

3.7

0.05

2.5

20

3.8

0.10

3/16

8.0

–

3.9

0.15

Ω

nsec

V

Cout = 1000pF

Vcc sweep down

*

BD9851EFV

Electrical characteristics (Unless otherwise specied, Ta=25˚C, Vcc=12V, fosc=300kHz, STB=3V)

Item Symbol

Limits

Typ. max.min.

Unit

[Total device]

Standby mode circuit current

Operation mode circuit current

Iccst

Icc

1.5

–

2.5

5

4.1

μA

mA

[Reference voltage block]

REF

Output voltage

Input stability

V

DVli

2.475

–

2.500

–

2.525

10

V

mV

Conditions

STB=0V

FB1, FB2=0V

Io=–0.1mA

Vcc= 4Vto18V, Io=–0.1mA

Load stability

Short circuit mode output current

[Oscillator block]

Oscillation frequency

Oscillation frequency regulation

[Error Amp block]

Threshold voltage

Input oset voltage

Common-mode input voltage range

Input bias current

Voltage gain

Frequency bandwidth

Maximum output voltage

Minimum output voltage

Output sink current

Output source current

[PWM comparator block]

0% threshold voltage

100% threshold voltage

DTC bias current

[FET driver block]

ON resistance

DVlo

Ios

fosc

Dfosc

Vthea

Vofst

Vcm

Ibias

Av

Bw

Vfbh

Vfbl

Isink

Isource

Vth0

Vth100

Idtc

R

ONN

R

ONP

–45

270

–2

0.98

–10

0.3

–150

60

REF –0.1

V

1.6

–260

1.21

1.74

–1

1.5

–

3

–

1

–

–12

300

0

1.00

0

–

–70

75

6

–

6

–160

1.31

1.84

–

3

2

10

–3

330

2

1.02

10

2.0

–

90

13

REF

V

0.1

16

–90

1.41

1.94

1

3

2

mV

mA

kHz

%

mV

nA

dB

MHz

mA

μA

Ω

Io=–0.1mA to –1mA

R

RT=24kΩ, CCT=220pF

Vcc= 4Vto18V

Ch1

V

Ch2

V

DC

MHz

V

FB pin

FB voltage

V

FB voltage

V

When OUT=Lo

When OUT=Hi

*Design guarantee

SEL1 input voltage range

[Control block]

Threshold voltage

Sink current

[Short circuit protection circuit (SCP) block]

Timer start voltage

Threshold voltage

Standby mode voltage

Source current

Vthscp

Vstscp

Vsoscp

[Under voltage lockout block (UVLO)]

Threshold voltage

Hysteresis width

Design guarantee

*

DVuvlo

Vselh

Vsell

Vstb

Istb

Vtime

Vuvlo

Vcc– 0.2

0

0.6

6

2.2

1.4

–

–3.2

3.58

0.05

–

1.5

15

2.3

1.5

10

–2.0

3.7

0.11

4/16

–

1.5

15

2.3

1.5

10

–2.0

3.7

0.11

V

μA

V

mV

μA

V

In step-down switching

STB=3V

FB voltage

SCP voltage

SCP=0.75V

Vcc sweep down

Characteristic data

(BD9850FVM)

1.02

1.015

1.01

1.005

1

0.995

0.99

0.985

0.98 –40 –20 0 20 40 60 80

ERROR-AMP. THRESHOLD VOLTAGE : VINV(V )

AMBIENT TEMPERATURE : Ta(˚C) FB VOLTAGE : VFB(V )

100

90

87

70

60

50

40

30

ON DUTY : DON(%)

20

10

0

1.5 1.6 1.7 1.8 1.9 2 2.1 2.2

Fig.1 Error Amp threshold voltage vs. Ambient temperature Fig.2 FB voltage vs. ON Duty

1000

900

800

700

600

500

400

300

200

100

OUT SOURCE CURRENT : IOUT [mA]

0

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2

(VCC-OUT)VOLTAGE : VO(V)

Vcc=10V

Vcc=7V

Vcc=4V

1000

900

800

700

600

500

400

300

200

100

OUT SINK CURRENT : IOUT [mA]

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2

Vcc=10V

OUT VOLTAGE : VO(V )

Vcc=7V

Vcc=4V

Fig.3 (Vcc-OUT) Voltage vs. Output source current

2.53

2.52

2.51

[V]

REF

2.5

2.49

VOLTAGE:V

REF

V

2.48

2.47

–40 –20 0 20 40 60 80 –40 –20 0 20 40 60 80

AMBIENT TEMPERATURE : Ta [˚C] AMBIENT TEMPERATURE : Ta [˚C]

Fig.5 V

REF vs. Ambient temperature Fig.6 Oscillation frequency vs. Ambient temperature

Fig.4 Output voltage vs. Output sink current

650

640

630

620

610

RT=24kΩ

600

590

580

570

560

OSCILLATING FREQUENCY : FOSC [kHz]

550

5/16

(BD9851EFV)

1.02

1.015

1.01

1.005

1

0.995

0.99

0.985

0.98 –40 –20 0 20 40 60 80

ERROR-AMP. THRESHOLD VOLTAGE : VEATH (V)

AMBIENT TEMPERATURE : Ta(˚C)

Fig.7 Error Amp threshold voltage vs. Ambient temperature

1000

900

800

700

600

500

400

300

200

100

OUT SOURCE CURRENT : IOUT (mA)REFERENCE VOLTAGE : VREF (V )

0

0 0.5 1 1.5 2 2.5 3 3.5 4

Vcc=20V

Vcc=12V

Vcc=4V

(Vcc-OUT) VOLTAGE : VO(V)

Fig.9 (Vcc-OUT) Voltage vs. Output source current

100

90

80

70

60

50

40

30

ON DUTY : DON (%)

fosc=1MHz

20

10

0

1.2 1.3 1.4 1.5 1.6 1.7 1.8 19

fosc=300kHz

DTC VOLTAGE : VDTC (V)

Fig.8 FB voltage vs. ON Duty

1000

900

800

700

600

OUT (mA)

500

400

300

200

100

0

0 0.5 0 1.5 2 2.5 3 3.5 4

Vcc=20V

Vcc=12V

Vcc=4V

OUT VOLTAGE : VO (V )

Fig.10 Output voltage vs. Output sink current

2.55

2.54

2.53

2.52

2.51

2.5

2.49

2.48

2.47

2.46

2.45 –40 –20 0 20 40 60 80

320

315

310

305

300

295

290

285

OSCILLATING FREQUENCY : FOSC (kHz) OUT SINK CURRENT : I

280

–40 –20 0 20 40 60 80

AMBIENT TEMPERATURE : Ta(˚C) AMBIENT TEMPERATURE : Ta(˚C)

Fig.11 V

REF vs. Ambient temperature

Fig.12 Oscillation frequency vs. Ambient temperature

RRT=24kΩ CCT=220pF

6/16