Fujitsu MB39A105 User Manual

FUJITSU SEMICONDUCTOR

DATA SHEET

ASSP For Power Supply Applications
(General Purpose DC/DC Converter)

1-ch DC/DC Converter IC

for low voltage

MB39A105

DESCRIPTION

■■■■

The MB39A105 is 1-channel DC/DC converter IC using pulse width modulation (PWM). This IC is ideal for up
conversion.
The minimum operating voltage is lo w (1.8 V) , and the MB39A105 is best for built-in power supply such as LCD
monitors. Also the short-circuit protection detection output function prevents input/output short on a chopper type
up-converter .
This product is covered by US Patent Number 6,147,477.

DS04-27233-2E

FEATURES

■■■■

• Power supply voltage range : 1.8 V to 6 V

• Reference voltage accuracy : ± 1 %

• High-frequency operation capability : 1 MHz (Max)

• Built-in standby function: 0 µA (Typ)

• Built-in timer-latch short-circuit protection circuit

• Built-in short-circuit protection detection output function

• Built-in soft-start circuit independent of loads

• Built-in totem-pole type output for Nch MOS FET

• Package : TSSOP-8P (Thickness 1.1 mm Max)

PACKAGE

■■■■

8-pin plastic TSSOP

(FPT-8P-M05)

MB39A105

PIN ASSIGNMENT

■■■■

(TOP VIEW)

−INE

CSCP

VCC

SCPOD

1

2

3

4

(FPT-8P-M05)

8

7

6

5

FB

RT

GND

OUT

2

MB39A105

PIN DESCRIPTION

■■■■

Pin No. Symbol I/O Descriptions

1 −INE I Error amplifiers (Error Amp) inverted input terminal
2CSCP Timer-latch short-circuit protection capacitor connection terminal
3VCC Power supply terminal

Open drain output terminal for short-circuit protection detection

4SCPODO

5 OUT O External Nch FET gate drive terminal
6GND Ground terminal
7RT Triangular wave oscillation frequency setting resistor connection terminal
8 FB O Error Amplifier (Error Amp) output terminal

During timer-latch short-circuit protection operation : Output “High-Z”
During normal operation : Output “L”

3

MB39A105

BLOCK DIAGRAM

■■■■

1

−INE

FB

VREF

8

VREF

Error Amp

−
+

+

(0.5 V ± 1%)

SCP
Comp.

+

−

(0.9 V)

+

−

(0.7 V)

(0.3 V)

PWM
Comp.

SCPODVCC

43

I

O = 400 mA

at VCC = 3.3 V

Nch

Drive

OUT

65GND

CSCP

2

(1.0 V)

+

−

UVLO

L : UVLO release

SQ
R

±10%

OSC

RT

RT Current

bias

VREF
(1.27 V)

7

VREF

Power

ON/OFF

CTL

4

ABSOLUTE MAXIMUM RATINGS

■■■■

MB39A105

Parameter Symbol Condition

Unit

Min Max

Rating

Power supply voltage V
Output current I
Output peak current I
Power dissipation P
Storage temperature T

CC VCC terminal  7V
O OUT terminal  35 mA

OP Duty ≤ 5% (t = 1/fOSC×Duty)  700 mA

D Ta ≤ +25 °C  490* mW

STG −55 +125 °C

* : The packages are mounted on the epoxy board (10 cm × 10 cm).
WARNING: Semiconductor devices can be permanently damaged by application of stress (voltage, current,

temperature, etc.) in excess of absolute maximum ratings. Do not exceed these ratings.

RECOMMENDED OPERATING CONDITIONS

■■■■

Parameter Symbol Condition

Power supply voltage V
Input voltage V
SCPOD terminal output voltage V
SCPOD terminal output current I
Output current I

Min Typ Max

CC VCC terminal 1.8  6V
INE −INE terminal 0  VCC − 0.9 V

SCPOD SCPOD terminal 0  6V

SCPOT SCPOD terminal 0  2mA

O OUT terminal −30 +30 mA

Value

Unit

Oscillation frequency fosc  100 500 1000 kHz
Timing resistor R
Short-circuit detection capacitor C

T RT terminal 3.3 7.5 33 kΩ

SCP CSCP terminal  0.22 1.0 µF

Operating ambient temperature Ta −30 +25 +85 °C

WARNING: The recommended operating conditions are required in order to ensure the normal operation of the

semiconductor device. All of the device’s electrical characteristics are warranted when the device is
operated within these ranges.

Always use semiconductor devices within their recommended operating condition ranges. Operation
outside these ranges may adversely affect reliability and could result in device failure.

No warranty is made with respect to uses, operating conditions, or combinations not represented on
the data sheet. Users considering application outside the listed conditions are advised to contact their
FUJITSU representatives beforehand.

5

MB39A105

ELECTRICAL CHARACTERISTICS

■■■■

Parameter

1. Under voltage
lockout
protection circuit
block [UVLO]

2. Short-circuit
protection block
[SCP]

3. Triangular
wave oscillator

[OSC]

block

4. Soft-start block
[CS]

5. Error amplifier
block [Error Amp]

6. PWM compar­ator block
[PWM Comp.]

7.Output block
[Drive]

8. General block

Threshold voltage V

Threshold voltage V
Short-circuit detection time

setting difference voltage
Input source current I
Reset voltage VRST 3VCC = 1.1 1.3 1.5 V
SCPOD terminal output

leak current
SCPOD terminal output on

resistor
Oscillation frequency fosc 5 RT = 7.5 kΩ 450 500 550 kHz
Frequency temperature

variation
Charge current I
Threshold voltage V

Input bias current IB 1 −INE = 0 V −120 −30  nA
Voltage gain AV 8DC  70*  dB
Frequency band width BW 8 A

Output voltage
Output source current I

Output sink current ISINK 8FB = 0.5 V 100 300 µA

Maximum duty cycle Dtr 5 RT = 7.5 kΩ 85 90 95 %

Output source current I

Output sink current I

Output ON resistor
Standby current ICCS 3RT = OPEN  010µA

Power supply current I

(VCC = 3.3 V, Ta = +25 °C)

Symbol

∆V

CSCP 2CSCP = 0.85 V −1.76 −0.88 −0.44 µA

I

LEAK 4SCPOD = 3.3 V  01.0µA

R

∆f

f

OSC

Pin

No

TLH 3VCC = 1.15 1.35 1.55 V

TH 2  0.95 1.00 1.05 V

CSCP 2  0.15 0.20 0.25 V

ON 4SCPOD = 1 mA  50 100 Ω

OSC/

CS 2CSCP = 0 V −16 −11 −6 µA

TH 1FB = 0.5 V 0.495 0.5 0.505 V

5Ta = 0 °C to +85 °C  1* %

Conditions

V = 0 dB  1.1*  MHz

Min Typ Max

Value

VOH 8  1.17 1.27 1.37 V

VOL 8 40 200 mV

SOURCE 8FB = 0.5 V −80 −50 µA

OUT = 0 V,

SOURCE 5

Duty ≤ 5%

−400*  mA

(t = 1/fosc×Duty)
OUT = 3.3 V,

SINK 5

Duty ≤ 5%

 400*  mA

(t = 1/fosc×Duty)

R

OH 5OUT = −15 mA  4.0* Ω

ROL 5OUT = 15 mA  3.0 6.0 Ω

CC 3RT = 7.5 kΩ1.2 1.8 mA

Unit

*: Standard design value.

6

TYPICAL CHARACTERISTICS

■■■■

MB39A105

Power Supply Current vs. Power Supply Voltage

5

4

3

2

1

0

Power supply current ICC (mA)

0246810

Power supply voltage V

Ta = +25 °C
RT = 7.5 kΩ

CC (V)

Error Amplifier Threshold Voltage vs.

Power Supply Voltage

1.0

0.9

0.8

0.7

0.6

VTH (V)

0.5

0.4

0.3

Voltage

0.2

0.1

Error Amplifier Threshold

0.0
0246810

Ta = +25 °C
VCC = 3.3 V

Power supply voltage VCC (V)

Power Supply Current vs. RT Terminal Current

5.0

4.5

4.0

CC (mA)

3.5

3.0

2.5

2.0

1.5

1.0

0.5

Power supply current I

0.0
0 1020304050

I

CC

Ta = +25 °C
VCC = 3.3 V

RT terminal current IRT (µA)

Error Amplifier Threshold Voltage vs.

Ambient Temperature

0.52

0.51

VTH (V)

0.50

0.49

Voltage

Error Amplifier Threshold

0.48

−40 −20 0 20 40 60 80 100

Ambient temperature Ta (°C)

VCC = 3.3 V
RT = 7.5 kΩ

Triangular Wave Oscillation Frequency vs.

Power supply voltage

600

550

fOSC (kHz)

500

450

Frequency

Triangular Wave Oscillation

400

1234567

Power supply voltage V

Ta = +25 °C
RT = 7.5 kΩ

CC (V)

(Continued)

7

MB39A105

Triangular Wave Oscillation Frequency

vs. Timing Resistor

10000

1000

OSC (kHz)

100

frequency f

Triangular wave oscillation

10

1 10 100

Timing resistor RT (kΩ)

Max On Duty vs.

Triangular Wave Oscillation Frequency

100

95

Ta = +25 °C
VCC = 3.3 V

Ta = +25 °C
VCC = 3.3 V

Triangular Wave Oscillation Frequency

vs. Ambient Temperature

600

550

OSC (kHz)

500

450

frequency f

Triangular wave oscillation

400

−40 −20 0 20 40 60 80 100

Ambient temperature Ta (°C)

VCC = 3.3 V
RT = 7.5 kΩ

90

85

80

Max On Duty (%)

75

70

10 100 1000 10000

Triangular wave oscillation frequency f

Error Amplifier Gain and Phase

vs. Frequency

40
30
20
10

V (dB)

−10

−20

Gain A

−30

−40

ϕ

0

Ta = +25 °C
VCC = 3.3 V

AV

OSC (kHz)

180

90

0

−90

Phase φ (deg)

−180

IN

10 kΩ

1 µF

+

10 kΩ

2.4 kΩ

10
11

240 kΩ

−
+

+

1.24 V

9

OUT

Error Amp

100 1 k 10 k 100 k 1 M 10 M

Frequency f (Hz)

(Continued)

8

(Continued)

Power Dissipation vs. Ambient Temperature

600

500
490

400

300

200

100

Power dissipation PD (mW)

0

−40 −20 0 20 40 60 80 100

Ambient temperature Ta ( °C)

MB39A105

9