NJM2392
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1
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Ver.2008-08-29
PWM DC/DC Converter IC
■GENERAL DESCRIPTION ■PACKAGE OUTLINE
■FEATURES
● Operating Voltage 3.0V to 40V
● Wide Oscillator Frequency 1kHz to 150kHz
● Internal High Power Transistor 1.5A max.
● Internal Over Current Limit Circuit
● PWM switching control
● Bipolar Technology
● Package Outline NJM2392D : DIP8
NJM2392M : DMP8
■PIN CONFIGURATION ■BLOCK DIAGRAM
The NJM2392 is a PWM DC/DC converter IC.
It features fixed frequency type PWM control for better nois
e
handling and to avoid intermittent oscillation observed in
a
simplified controller.
It is suitable for Step-Up, Step-Down and Inverting applications.
In addition, it contains a pulse-by-pulse current limit circui
t
and can be set by an external resistance. NJM2392D NJM2392M
PIN FUNCTION
1. CS
2. ES
3. CT
4. GND
5. IN-
6. V+
7. SI
8. CD
NJM2392D
NJM2392M
1 8
2 7
3 6
4 5
1
1.5A
OSC Block
MAX
ON Duty
9:1
4
3
2
8
5
6
7
V+
ES
GND
PW M
Logic
R
S
Q
Vref
1.25V
CD
CT
CS
SI
IN-
300mV
Ipk Sense
PWM COMP
Error AMP
160
Ω
Buffer
NJM2392
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2
-Ver.2008-08-29
■ABSOLUTE MAXIMUM RATINGS (Ta=25°C)
PARAMETER SYMBOL MAXIMUM RATINGS UNIT
Maximum Supply Voltage V+ 40 V
Comparator Input Voltage VIR -0.3 ~ 40 (note) V
Output Driver Voltage VC(driver) 40 V
Output Switch Voltage VSW 40 V
Output Driver Current IC(driver) 100 mA
Output Switch Current ISW 1.5 A
Power Dissipation PD
DIP8
DMP8
875
580 (*1)
750 (*2)
mW
Operating Temperature Range Topr -40 ~ +85 °C
Storage Temperature Range Tstg -50 ~ +150 °C
(note) When supply voltage is less than 40V, the absolute maximum input voltage is equal to the supply voltage.
(*1) At on PC board : 114.3mm × 76.2mm × 1.6mm(2 layer FR-4) : Conform to EIA/JEDEC
(*2) At on PC board :114.3mm × 76.2mm × 1.6mm(4 layer FR-4) : Conform to EIA/JEDEC
■POWER DISSIPATION vs. AMBIENT TEMPERATURE
0
200
400
600
800
1000
0255075100
Ambient Temperature
Ta (oC)
Power Dissipation PD (mW)
Power Dissipation vs. Ambient Temperature
(Topr=-40~+85
oC, Tj= ~150oC)
DIP8
DMP8
At on 4 layer PC Board
At on 2 layer PC Board
NJM2392
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3
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Ver.2008-08-29
■ELECTRICAL CHARACTERISTICS
DC Characteristics (V+=5V, Ta=25°C)
PARAMETER SYMBOL TEST CONDITIONS MIN. TYP. MAX. UNIT
OSCILLATOR BLOCK
Oscillation Frequency fOSC IN-=0V, CT=1nF 18 27 36 kHz
Charge Current Ichg 11 18 27 µA
Discharge Current Idis 110 180 300 µA
Voltage Swing VOSC C
T=1nF – 0.5 – VP-P
Discharge to Charge
Current Ratio Iratio I
chg/Idis – 9 – –
CURRENT LIMIT
Peak Current
Sense Voltage Vipk 250 300 350 mV
OUTPUT SWITCH
Saturation Voltage 1 Vsat1 Darlington Connection
(CS=CD), ISW=0.7A – 1.0 1.3 V
Saturation Voltage 2 Vsat2 ISW=0.7A, IC(driver)=50mA
(Forced β≈14) – 0.5 0.7 V
Output Transistor
Bias Resistance Rbias – 160 – Ω
DC Voltage Gain hFE I
SW=0.7A,VCE=5.0V 35 120 – –
Collector Off-State Current IC(Off) V
CE=40V – 0.01 1 µA
ERROR AMPLIFIER
Threshold Voltage Vth 1.225 1.250 1.275 V
Input Bias Current IIB IN-=0V – 300 900 nA
GENERAL CHARACTERISTICS
Operating Current ICC C
T=1nF, SI=V+, IN->Vth, ES=GND – 2.8 4.0 mA
(note) Output switch tests are performed under pulsed conditions to minimize power dissipation.
NJM2392
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4
-Ver.2008-08-29
■TYPICAL APPLICATIONS
Step-Down Converter
1
NJM2392
43
2
CT
8
6
7
D1
R2
L1
5
R1
RSC
CIN COUT
VIN
VOUT
C1
Step-Up Converter
1
NJM2392
43
2
RC
CT
8
6
7
D1
R2
L1
5
R1
RSC
CIN
COUT
VIN VOUT
C1
Inverting Converter
1
NJM2392
43
2
CT
8
6
7
D1
R2
L1
5
R1
RSC
CIN
COUT
VIN
VOUT
C1
D1 use to schottky diode.
NJM2392
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5
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Ver.2008-08-29
■ TYPICAL APPLICATIONS
Step-Down Converter (High Current)
Step-Up Converter (High Current)
D1 use to schottky diode.
1
NJM2392
4 3
2
CT
F
8
6
7
5
RSC
CIN
VIN RBE
RBC
D1
R2
L1
R1 COUT
VOUT
C1
1
NJM2392
4 3
2
RC2
CT
8
6
7
L1
5
RSC
CIN
VIN
RC1
RBE
D1
R2
R1
COUT
VOUT
C1
NJM2392
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■TIMING CHART
Oscillator
Waveform
Error AMP
Output
Switch Output
OFF
ON
OSC Block to
FF, NOR
HIGH
LOW
Ipk Sense
Output
HIGH
LOW
NJM2392
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Ver.2008-08-29
■TYPICAL CHARACTERISTICS
1
10
100
10 100 1000 10000 100000
Oscillator Frequency
fOSC (kHz)
Oscillator Frequency vs. Timing Capacitor
(V+=5V, SI=V+, Pin 5=GND, Ta=25
oC)
Timing Capacitor C
T (pF)
1
10
100
10 100 1000 10000
Switch ON/OFF Time
tON, tOFF (µs)
Switch ON/OFF TIme vs.Timing Capacitor
(V+=5V, SI=V+, Pin 5=GND, Ta=25
oC)
Timing Capacitor CT (pF)
tON
tOFF
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
Saturation Voltage 1 vs. Collector Current
(V+=5V, CS=CD, Ta=25oC)
Collector Current IC (A)
Saturation Voltage 1 Vsat1 (V)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
Saturation Voltage 2 vs. Collector Current
(V+=5V, Ic(driver)=50mA, β≅14, Ta=25oC)
Collector Current I
C (A)
Saturation Voltage2 Vsat2 (V)
0
100
200
300
400
500
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
Input Bias Current vs. IN- Terminal Voltage
(V+=5V, Ta=25oC)
IN- Terminal Voltage (V)
Input Bias Current IIB (nA)
0
1
2
3
4
010203040
Operating Current vs. Operating Voltage
(CT=1nF, SI=V+, IN->Vth, Es=GND, Ta=25oC)
Operating Voltage V
+ (V)
Operating Current ICC (mA)
NJM2392
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-Ver.2008-08-29
■TYPICAL CHARACTERISTICS
1.2
1.21
1.22
1.23
1.24
1.25
1.26
1.27
1.28
-50 -25 0 25 50 75 100 125 150
Ambient Temperature Ta (oC)
Threshold Voltage Vth (V)
Threshold Voltage vs. Temperature
(V+=5V)
8
9
10
11
12
-50 -25 0 25 50 75 100 125 150
Ambient Temperature Ta (
oC)
Discharge to Charge Current
Ratio Iratio
Discharge to Charge Ratio vs. Temperature
(V+=5V)
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 (oC)
Saturation Voltage 1 Vsat1 (V)
Saturation Voltage 1 vs. Temperature
(V+=5V, CS=CD, ISW =0.7A)
0
0.2
0.4
0.6
0.8
-50 -25 0 25 50 75 100 125 150
Ambient Temperature Ta (
oC)
Saturation Voltage 2 Vsat2 (V)
Saturation Voltage 2 vs. Temperature
(V+=5V, Isw=0.7A, Ic(driver)=50mA, β≅14)
240
260
280
300
320
340
360
-50 -25 0 25 50 75 100 125 150
Ambient Temperature Ta (
oC)
Current Limit Sense Voltage Vipk (mV)
Current Limit Sense Voltage vs. Temperature
(V+=5V)
0
1
2
3
4
5
-50 -25 0 25 50 75 100 125 150
Ambient Temperature Ta (
oC)
Operating Current ICC (mA)
Operating Current vs. Temperature
(V+=5V, CT=1nF, SI=V+, IN->Vth, Es=GND)
NJM2392
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9
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Ver.2008-08-29
MEMO
[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.
