NJM2374AM-(T2) - New Japan Radio Co., Ltd.

NJM2374A

Ver 2.

0

- 1 -

PWM DC/DC CONVERTER IC

■GENERAL DESCRIPTION ■PACKAGE OUTLINE

■FEATURES

●Operating Voltage (2.5V to 40V)

●Wide Oscillator Frequency (100Hz to 100kHz)

●Internal High Power Transistor 1.5A (max.)

●Internal Over Current Limit Circuit

●PWM form Switching Power Supply Control

●Bipolar Technology

●Package Outline DIP8, DMP8, SSOP14

■PIN CONFIGURATION

NJM2374AD NJM2374AM

NJM2374AV

The NJM2374A is a PWM DC/DC converter IC.

It features fixed frequency type PWM control for better

noise handling and to avoid intermittent oscillation observed

in a simplified controller.

It is suitable for Step-Up, Step-Down and Inverting

applications for EMI sensitive application.

NJM2374AD

NJM2374AM

1.C

S

2.E

S

3.C

T

4.GND

5.IN

+

6.V

+

7.S

I

8.C

D

PIN FUNCTION

1.C

S

2.NC

3.E

S

4.NC

5.C

T

6.NC

7.GND

8.IN

+

9.NC

10.V

+

11.NC

12.S

I

13.NC

14.C

D

PIN FUNCTION

NJM2374AV

1

4

3

2

8

5

6

7

1

4

3

2

5

7

6

14

11

12

13

10

8

9

NJM2374A

- 2 -

■BLOCK DIAGRAM

1

1.5A

Maximum

ON duty 9:1

OSC BLOCK

4

3

2

8

5

6

7

V

+

E

S

GND

PWM

Logic

R

SQ

Vref

1.25V

±2%

C

D

C

T

C

S

I

IN

+

Vth=300mV

Ipk Sense

PWM COMP

ERR.AMP

160Ω

(DIP8, DMP8: PACKAGE)

1

1.5A

7

5

3

14

8

10

12

V

+

E

S

GND

R

SQ

Vref

1.25V

±2%

C

D

C

T

C

S

I

IN

+

Vth=300mV

Ipk Sense

PWM COMP

ERR.AMP

2

NC

4

NC

6NC 9 NC

11 NC

13 NC

160Ω

Maximum

ON duty 9:1

OSC BLOCK

PWM

Logic

(SSOP14: PACKAGE)

NJM2374A

-

3

-

■ABSOLUTE MAXIMUM RATINGS (Ta=25°C )

PARAMETER SYMBOL RATINGS UNIT

Maximum Supply Voltage V

+

40 V

Output Switch Current I

SW

1.5 A

Output Switch Voltage V

SW

40 V

Comparator Input Voltage V

IR

-0.3 ~ 40 V

Power Dissipation

P

D

(DIP8) 875

(DMP8) 750 (note1)

(SSOP14) 375

mW

Operating Temperature Range Topr -40 ~ +85 °C

Storage Temperature Range Tstg -50 ~ +150 °C

(note1) At on PC board.

■POWER DISSIPATION vs. AMBIENT TEMPERATURE

In the case of SSOP packaging, the power dissipation should carefully

be considered when designing this parts.

0

200

400

600

800

1000

25 50 75 100

Ambient Temperature Ta (°C)

Power Dissipation P

D

(mW)

(Topr=-40 to +85°C,Tj= to +150°C)

NJM2374AM

At on PC board

NJM2374AD

NJM2374AV

NJM2374A

- 4 -

■ELECTRICAL CHARACTERISTICS

DC Characteristics (V

+

=5V, Ta=25°C)

PARAMETER SYMBOL TEST CONDITIONS MIN. TYP. MAX. UNIT

Operating Current I

CC

C

T

=1nF, S

I

=V

+

, IN

+

> V

th

, E

S

=GND – 2.8 4.0 mA

Charge Current I

chg

12 20 30 µA

Discharge Current I

dis

110 180 300 µA

Voltage Swing V

OSC

– 0.5 – V

P-P

Discharge to Charge

Current Ratio

I

ratio

S

I

=V

+

– 9 – –

Peak Current

Sense Voltage

V

ipk

I

chg

=I

dis

250 300 350 mV

Saturation Voltage 1 V

sat1

Darlington Connection

(C

S

=C

D

), I

SW

=0.7A

– 1.0 1.3 V

Saturation Voltage 2 V

sat2

I

SW

=0.7A, Ic(driver)=50mA

(Forced β≈14)

– 0.5 0.7 V

Output Transistor

Bias Resistance

R

bias

– 160 – Ω

DC Voltage Gain h

FE

I

SW

=0.7A, V

CE

=5.0V 35 120 – –

Collector Off-State

Current

I

C(Off)

V

CE

=40V – 10 – nA

Threshold Voltage V

th

1.225 1.250 1.275 V

Input Bias Current I

IB

IN

+

=0V – 40 400 nA

(note) Output switch tests are performed under pulsed conditions to minimize power dissipation.

■TIMING CHART

Oscillator

Waveform

Reference

Voltage

Output

Voltage

Collector-Emitter

Voltage

High Voltage

Detect

Current-Limit

A

ctive Point

OFF

ON

OSC Block to

FF Reset

HIGH

LOW

NJM2374A

-

5

-

■TIPICAL CHARACTERISTICS

Operating Current vs. Operating Voltage

(CT=1nF,SI=V+,IN+>Vth,ES=GND,Ta=25°C)

0

1

2

3

4

0 5 10 15 20 25 30 35 40

Operating Voltage V+ (V)

Operating Current ICC (mA)

Oscillator Frequency vs. Timing Capacitor

(V+=5V,SI=V+,Pin5=GND,Ta=25°C)

1

10

100

1000

100 1000 10000

Timing Capacitor CT (pF)

Oscillator Frequency

fOSC (kHz)

Saturation Voltage 1 vs. Collector Current

(V+=5V,CS=CD,Ta=25°C)

0

0.5

1

1.5

2

00.511.52

Collector Current IC (A)

Saturation Voltage 1 Vsat1 (V)

Switch ON/OFF Time vs. Timing Capacitor

(V+=5V,SI=V+,Pin5=GND,Ta=25°C)

1

10

100

1000

100 1000 10000

Timing Capacitor CT (pF)

Switch ON/OFF Time

tON / tOFF (μS)

tON

tOFF

Saturation Voltage 2 vs. Collector Current

(V+=5V,Ic(driver)=50mA,β=14,Ta=25°C)

0

0.5

1

1.5

2

0 0.5 1 1.5 2

Collector Current IC (A)

Saturation Voltage 2 Vsat2 (V)

NJM2374A

-

6

-

■TIPICAL CHARACTERISTICS

Saturation Voltage 2 vs. Temperature

(V+=5V,ISW=0.7A,Ic(driver)=50mA,β=14)

0

0.2

0.4

0.6

0.8

-50 -25 0 25 50 75 100 125 150

Ambient Temperature Ta (°C)

Saturation Voltage 2 Vsat2 (V)

Discharge to Charge Current Ratio vs.

Temperature (V+=5V,SI=V+)

6

7

8

9

10

-50 -25 0 25 50 75 100 125 150

Ambient Temperature Ta (°C)

Discharge to Charge Current

Ratio Iratio

Saturation Voltage 1 vs. Temperature

(V+=5V,CS=CD,ISW=0.7A)

0.6

0.7

0.8

0.9

1

1.1

1.2

-50 -25 0 25 50 75 100 125 150

Ambient Temperature Ta (°C)

Saturation Voltage 1 Vsat1 (V)

Operating Current vs Temperature

(V+=5V,CT=1nF,SI=V+,IN+>Vth,ES=GND)

0

1

2

3

4

5

-50 -25 0 25 50 75 100 125 150

Ambient Temperature Ta (°C)

Operating Current ICC

(mA)

Threshold Voltage vs. Temperature

(V+=5V)

1.22

1.24

1.26

1.28

1.3

-50 -25 0 25 50 75 100 125 150

Ambient Temperature Ta (°C)

Threshold Voltage Vth (V)

NJM2374A

-7 -

■TYPICAL APPLICATIONS

Step-Down Converter

In the case of Step-Down Conversion with the internal power transistor,

the Output Voltage must be set lower than 6V.

Step-Up Converter

Inverting Converter

D1 use to schottky diode.

In the case of SSOP packaging, the power dissipation should carefully

be considered when designing this parts.

1

NJM2374A

4 3

2

CT

470pF

8

6

7

D1

R2 3.6kΩ

L1 220µH

5

R1

1.2kΩ

RSC

0.22Ω

CIN

100µF

COUT

470µF

VIN=25V

VOUT=5.0V

1

NJM2374A

4 3

2

RC

180Ω

CT

1500pF

8

6

7

D1

R2

46kΩ

L1 180µH

5

R1

2kΩ

RSC

0.22Ω

CIN

100µF

COUT

150µF

VIN=14V VOUT=30V

1

NJM2374A

43

2

C

T

1300pF

8

6

7

D1

R2 953Ω

L1

90µH

5

R1

8.2kΩ

R

SC

0.22Ω

C

IN

100µF

C

OUT

1000µF

V

IN

=5V

V

OUT

=-12V

NJM2374A

-

8

-

Step-Down Converter (High Current)

Step-Up Converter (High Current)

D1 use to schottky diode.

[CAUTION]

The specifications on this databook are only

given for information , without any guarantee

as regards either mistakes or omissions. The

application circuits in this databook are

described only to show representative usages

of the product and not intended for the

guarantee or permission of any right including

the industrial rights.

1

NJM2374A

43

2

C

T

330pF

8

6

7

D1

R2 70kΩ

L1 33µF

5

R1

10kΩ

R

SC

0.05Ω

C

IN

300µF

C

OUT

300µF

V

IN

=20V

V

OUT

=10V

R

BE

75Ω

R

BC

300Ω

2SA1010

1

NJM2374A

4 3

2

RC2

680Ω

CT

330pF

8

6

7

D1

R2

46kΩ

L1 22µH

5

R1

10kΩ

RSC

0.075Ω

CIN

940µF

COUT

940µF

VIN=5V VOUT=7V

RC1

100Ω

2SC3255

RBE

220Ω