ROHM BD3550HFN Technical data

TECHNICAL NOTE

High-performance Regulator IC Series for PCs

Ultra Low Dropout
Linear Regulators for PC

BD3550HFN, BD3551HFN, BD3552HFN (0.5～2.0A)

● Description
BD3550HFN,BD3551HFN,BD3552HFN ultra low-dropout linear chipset regulator operates from a very low input supply, and
offers ideal performance in low input voltage to low output voltage applications. It incor porates a bui lt-in N-MOSFET power
transistor to minimize the input-to-output voltage differential to the ON resistance (R
lowering the dropout voltage in this way, the regulator realizes high current output (Iomax=2.0A <BD3552HFN>) with
reduced conversion loss, and thereby obviates the switching regulator and its power transistor, choke coil, and rectifier
diode. Thus, BD3550HFN,BD3551HFN,BD3552HFN is designed to ena ble significant package profile d ownsizing and cost
reduction. An external resistor allows the entire range of output voltage configurations bet ween 0.65 and 2.7V, while the
NRCS (soft start) function enables a controlled output voltage ramp-up, which can be programmed to whatever power
supply sequence is required.

● Features

1) Internal high-precision reference voltage circuit(0.65V±1%)

2) Built-in VCC undervoltage lockout circuit

3) NRCS (soft start) function reduces the magnitude of in-rush current

4) Internal Nch MOSFET driver offers low ON resistance (100mΩ <BD3552HFN typ>)

5) Built-in current limit circuit

6) Built-in thermal shutdown (TSD) circuit

7) Variable output (0.65～2.7V)

8) Small package HSON8 : 2.9×3×0.6(mm)

9) Tracking function

● Applications
Notebook computers, Desktop computers, LCD-TV, DVD, Digital appliances

● Line-up

It is available to select power supply voltage and maximum output voltage.

Maximum Output Voltage Package Vcc=5V

0.5A

1.0A BD3551HFN

2.0A BD3552HFN

HSON8

BD3550HFN

ON=100mΩ <BD3552HFN>) level. By

Oct. 2008

●Absolute maximum ratings

◎BD3550HFN,BD3551HFN,BD3552HFN

Parameter Symbol

BD3550HFN BD3551HFN BD3552HFN

Limit

Unit

Input Voltage 1 VCC +6.0 *1 V
Input Voltage 2 VIN +6.0 *1 V
Enable Input Voltage Ven -0.3～+6.0 V
Power Dissipation 1 Pd1 0.63 *2 W
Power Dissipation 2 Pd2 1.35 *3 W

Power Dissipation 3 Pd3 1.75 *4 W
Operating Temperature Range Topr -10～+100 ℃
Storage Temperature Range Tstg -55～+150 ℃
Maximum Junction Temperature Tjmax +150 ℃

*1 Should not exceed Pd.
*2 Reduced by 5.04mW/℃ for each increase in Ta≧25℃ (when mounted on a 70mm×70mm×1.6mm glass-epoxy board, 1-layer)
On less than 0.2% (percentage occupied by copper foil.
*3 Reduced by 10.8mW/℃ for each increase in Ta≧25℃ (when mounted on a 70mm×70mm×1.6mm glass-epoxy board, 1-layer)
On less than 7.0% (percentage occupied by copper foil.
*4 Reduced by 14.0mW/℃ for each increase in Ta≧25℃ (when mounted on a 70mm×70mm×1.6mm glass-epoxy board, 1-layer)

On less than 65.0% (percentage occupied by copper foil.

2/16

◎BD3550HFN,BD3551HFN,BD3552HFN

●Operating Voltage(Ta=25℃)

Parameter Symbol Min. Max. Unit
Input Voltage 1 VCC 4.3 5.5 V
Input Voltage 2 VIN 0.95 VCC-1 *5 V
Output Voltage Setting Range Vo VFB 2.7 V
Enable Input Voltage Ven 0 5.5 V
NRCS Capacity CNRCS 0.001 1 μF

*5 VCC and VIN do not have to be implemented in the order listed.

★This product is not designed for use in radioactive environments.

●Electrical Characteristics (Unless otherwise specified, Ta=25℃, VCC=5V, Ven=3V, VIN=1.8V, R1=3.9KΩ, R2=3.3KΩ)

Parameter Symbol

Bias Current ICC - 0.5 1.0 mA
VCC Shutdown Mode Current IST - 0 10 uA Ven=0V
Output Voltage VOUT - 1.200 - V
Output Voltage Temperature
Coefficient

Tcvo - 0.01 - %/℃

Feedback Voltage 1 VFB1 0.643 0.650 0.657 V
Feedback Voltage 2 VFB2 0.637 0.650 0.663 V Tj=-10 to 100℃

Load Regulation Reg.L - 0.5 10 mV
Line Regulation 1 Reg.l1 - 0.1 0.5 %/V VCC=4.3V to 5.5V

Line Regulation 2 Reg.l2 - 0.1 0.5 %/V VIN=1.2V to 3.3V

Standby Discharge Current Iden 1 - - mA Ven=0V, Vo=1V
[ENABLE]
Enable Pin
Input Voltage High
Enable Pin
Input Voltage Low

Enhi 2 - - V

Enlow 0 - 0.8 V

Enable Input Bias Current Ien - 7 10 μA Ven=3V
[FEEDBACK]
Feedback Pin Bias Current IFB -100 0 100 nA
[NRCS]
NRCS Charge Current Inrcs 14 20 26 μA Vnrcs=0.5V
NRCS Standby Voltage VSTB - 0 50 mV Ven=0V
[UVLO]
VCC Undervoltage Lockout
Threshold Voltage
VCC Undervoltage Lockout
Hysteresis Voltage

VccUVLO 3.5 3.8 4.1 V Vcc:Sweep-up

Vcchys 100 160 220 mV Vcc:Sweep-down

[AMP]
Gate Source Current I
Gate Sink Current I

Maximum output
current

Minimum dropout
voltage

BD3550HFN Io 0.5 - - A
BD3551HFN Io 1.0 - - A
BD3552HFN Io 2.0 - - A
BD3550HFN dVo - 200 300 mV Io=0.5A, VIN=1.2V, Ta=-10 to 100℃
BD3551HFN dvo - 200 300 mV Io=1.0A, VIN=1.2V, Ta=-10 to 100℃
BD3552HFN dVo - 200 300 mV Io=2.0A, VIN=1.2V, Ta=-10 to 100℃

- 1.6 - mA VFB=0, V

GSO

- 4.7 - mA VFB=VCC, V

GSI

Limit

Min. Typ. Max.

Unit Condition

Io=0 to 1A
(BD3550HFN Io=0A to 0.5A)

=2.5V

GATE

=2.5V

GATE

3/16

●Reference Data(BD3550HFN)

μ

v

v

v

v

v

v

v

v

μ

v

v

v

v

v

v

50mV/di

Vo

26mV

Vo

50mV/di

22mV

0.5A/di

Io

0.5A

0.5A/di

Io

0.5A

Io=0A→1A/μsec t(10μsec/div)

Fig.1 Transient Response

(0→0.5A)

Co=100μF, Cfb=1000pF

Io=0A→1A/μsec t(10μsec/div) Io=0A→1A/μsec t(10μsec/div)

Fig.2 Transient Response

(0→0.5A)

Co=47μF, Cfb=1000pF

50mV/di

Vo

14mV

50mV/div

Vo

23mV

Io

0.5A/di

0.5A

Io=1A→0A/μsec t(100μsec/div)

Fig.4 Transient Response

(0.5→0A)

Co=100

F, Cfb=1000pF

0.5A/div

Io

0.5A

Io=1A→0A/μsec t(100μsec/div)

Fig.5 Transient Response

(0.5→0A)

Co=47μF, Cfb=1000pF

50mV/di

0.5A/di

50mV/div

0.5A/div

Vo

40mV

Io

0.5A

Fig.3 Transient Response

(0→0.5A)

Co=22μF, Cfb=1000pF

Vo

33mV

Io

0.5A

Io=1A→0A/μsec t(100μsec/div)

Fig.6 Transient Response

(0.5→0A)

Co=22μF, Cfb=1000pF

●Reference Data(BD3551HFN)

Vo

50mV/di

35mV

Io

1.0A/di

Vo

50mV/div

1.0A

Io=0A→1A/μsec t(10μsec/div)

Fig.7 Transient Response

(0→1.0A)

Co=100μF, Cfb=1000pF

36mV

Fig.7 Transient Response (1.0→

0A)

F, Cfb=1000pF

1.0A/div

Io

1.0A

Co=100

Vo

50mV/div

46mV

Io

1.0A/div

1.0A

Io=0A→1A/μsec t(10μsec/div) Io=0A→1A/μsec t(10μsec/div)

Fig.8 Transient Response

(0→1.0A)

Co=47μF, Cfb=1000pF

Vo

50mV/div

46mV

Io=0A→1A/μsec t(10μsec/div)

Fig.8 Transient Response (0→

1.0A)

1.0A/div

Io

1.0A

Vo

50mV/di

55mV

Io

1.0A/di

1.0A

Fig.9 Transient Response

(0→1.0A)

50mV/di

Co=22μF, Cfb=1000pF

Vo

56mV

Io=0A→1A/μsec t(10μsec/div)

Fig.9 Transient Response (0→

1.0A)

1.0A/di

Io

1.0A

Io=1A→0A/μsec t(100μsec/div)

Fig.10 Transient Response

(1.0→0A)

Co=100μF, Cfb=1000pF

Io=1A→0A/μsec t(100μsec/div)

Fig.11 Transient Response

(1.0→0A)

Co=47μF, Cfb=1000pF

Io=1A→0A/μsec t(100μsec/div)

Fig.12 Transient Response

(1.0→0A)

Co=22μF, Cfb=1000pF

4/16

●Reference Data(BD3552HFN)

v

v

v

v

v

v

v

v

v

μ

v

v

v

v

v

v

v

Vo

50mV/di

2.0A/di

50mV/di

2.0A/di

26mV

Io

Io=0A→1A/μsec t(10μsec/div)

2.0A

Fig.13 Transient Response

(0→2.0A)

Co=100μF, Cfb=1000pF

Vo

54mV

Io

2.0A

Io=1A→0A/μsec t(100μsec/div)

Fig.16 Transient Response

(2.0→0A)

Co=100

F, Cfb=1000pF

●Reference Data(BD3551HFN)

Ven

2V/di

VNRCS

2V/di

Vo

1V/di

Fig.19 Waveform at output

t(200μsec/div)

start

VCC

Ven

VIN

Vo

VIN→VCC→Ven

Fig.22 Input sequence

Vo

50mV/di

89mV

Io

2.0A/di

Io=0A→1A/μsec t(10μsec/div)

2.0A

Fig.14 Transient Response

(0→2.0A)

Vo

50mV/di

2.0A/di

Co=47μF, Cfb=1000pF

83mV

Io

2.0A

Io=1A→0A/μsec t(100μsec/div)

Fig.17 Transient Response

(2.0→0A)

Co=47μF, Cfb=1000pF

Ven

2V/di

VNRCS

2V/div

Vo

1V/di

t(2msec/div)

Fig.20 Waveform at output OFF

VCC

Ven

VIN

Vo

Ven→VCC→VIN

Fig.23 Input sequence

50mV/di

2.0A/di

50mV/di

2.0A/div

VCC

Vo

117mV

Io

Io=0A→1A/μsec t(10μsec/div)

2.0A

Fig.15 Transient Response

(0→2.0A)

Co=22μF, Cfb=1000pF

Vo

117mV

Io

2.0A

Io=1A→0A/μsec t(100μsec/div)

Fig.18 Transient Response

(2.0→0A)

Co=22μF, Cfb=1000pF

VCC

Ven

VIN

Vo

Fig.21 Input sequence

Ven

VIN

Vo

VCC→Ven→VIN

Fig.24 Input sequence

VCC→VIN→Ven

5/16

●Reference Data(BD3551HFN)

1.25

VCC

Ven

VIN

Vo

Fig.25 Input sequence

0.80

0.75

0.70

0.65

0.60

0.55

ICC(mA)

0.50

0.45

0.40

0.35

0.30

-10 10 30 50 70 90
Ta(℃)

VCC

Ven

VIN

Vo

VIN→Ven→VCC Ven→VIN→VCC

Fig.26 Input sequence

1.2

1.0

0.8

0.6

ICC(uA)

0.4

0.2

100

0.0

-60 -30 0 30 60 90 120 150
Ta(℃)

1.23

1.21

Vo(V)

1.19

1.17

1.15

-101030507090
Ta(℃)

Fig.27 Ta-Vo (Io=0mA)

2.0

1.9

1.8

1.7

1.6

1.5

IIN(mA)

1.4

1.3

1.2

1.1

1.0

-101030507090

Ta(℃)

100

100

Fig.28 Ta-ICC

30

25

20

15

IIN(uA)

10

5

0

-60 -30 0 30 60 90 120 150
Ta(℃)

Fig.31 Ta-IINSTB

10

9
8
7
6
5

Ien(uA)

4
3
2
1
0

-101030507090
Ta(℃)

100

Fig.29 Ta-ISTB

25
24
23
22
21
20
19

INRCS(uA)

18
17
16
15

-101030507090
Ta(℃)

Fig.32 Ta-INRCS

150

140

130

)

Ω

120

RON(m

110

100

90

-10 10 30 50 70 90
Ta(℃)

Fig.30 Ta-IIN

20
15
10

5
0

IFB(nA)

-5

-10

-15

100 100

-20

-10 10 30 50 70 90
Ta(℃)

Fig.33 Ta-IFB

150

140

130

)

Ω

120

RON(m

110

100

90

100

2468

Vcc(V)

Fig.34 Ta-Ien

Fig.35 Ta-RON

(VCC=5V/Vo=1.2V)

6/16

Fig.36 VCC-RON