Fujitsu MB3817 Switching regulator controller Datasheet

FUJITSU SEMICONDUCTOR
DATA SHEET
DS04-27216-2E
ASSP For Power Supply Applications
BIPOLAR
Switching Regulator Controller
MB3817
■ DESCRIPTION
The MB3817 is a pulse width modulator (PWM) type switching regulator controller IC designed for low-voltage
and high-speed operation. This can be used in applications as down-conversion or down/up-conversion (Zeta
method).
With fewer external components and faster operating speed, the MB3817 enables reduction in power supply unit
size, making it ideal for use with internal power supplies in compact, high-performance portable devices.
■ FEATURES
•
•
•
•
•
•
•
•
•
Wide range of operating power supply voltages: 2.5 V to 18 V
Built-in high-precision reference voltage generator: 1.5 V ± 2%
High speed operation is possible: Max. 500 kHz
Wide input voltage range of error amplifier: 0 to VCC – 0.9 V
Built-in soft start function
Built-in timer/latch-actuated short-circuiting protection circuit
Totem-pole type output with adjustable on/off current (for PNP transistors)
Built-in standby function
Small package: SSOP-16P (FPT-16P-M05)
■ PACKAGE
16-pin Plastic SSOP
(FPT-16P-M05)
MB3817
■ PIN ASSIGNMENT
(TOP VIEW)
CT
1
16
VREF
RT
2
15
CTL
+IN
3
14
CSCP
−IN
4
13
CS
FB
5
12
GND
DTC
6
11
VE
CB1
7
10
OUT
CB2
8
9
V CC
(FPT-16P-M05)
2
MB3817
■ PIN DESCRIPTION
Pin no.
Pin name
I/O
Descriptions
1
CT
—
This pin connects to a capacitor for setting the triangular-wave frequency.
2
RT
—
This pin connects to a resistor for setting the triangular-wave frequency.
3
+IN
I
Error amplifier non-inverted input pin
4
–IN
I
Error amplifier inverted input pin
5
FB
O
Error amplifier output pin
6
DTC
I
Dead time control pin
7
CB1
—
Boot capacitor connection pin
8
CB2
—
Boot capacitor connection pin
9
VCC
—
Power supply pin
10
OUT
O
Totem-pole type output pin
11
VE
—
Output current setting pin
12
GND
—
Ground pin
13
CS
—
Soft start setting capacitor connection pin
14
CSCP
—
Short detection setting capacitor connection pin
15
CTL
I
Power supply control pin
When this pin is High, IC is inactive state
When this pin is Low, IC is standby state
16
VREF
O
Reference voltage output pin
3
MB3817
■ BLOCK DIAGRAM
CB1
OUT
7
FB
8
5
−IN
+IN
DTC
CB2
4
Error
− Amp.
3
+
PWM
9
+ Comp.
+
+
−
OFF current
setting
block
VCC
Q4
10
6
OUT
CS
CS
13
Q6
1µ
Soft Start
−
Comp.
+
Q1
(0.9 V)
−
D1
(0.5 V)
Q5
SCP
Comp.
11
VE
+
1.5 V
SCP
1µ
−1.4 V
−1.0 V
RS
Latch
OSC
1
2
CT
4
bias
RT
bias
UVLO
Q2
Q3
VCC
Power
Ref
(1.5 V) ON/OFF
14
16
CSCP VREF
12
GND
15
CTL
MB3817
■ ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Condition
Power supply voltage
VCC
—
Power dissipation
PD
Storage temperature
Tstg
Ta
+25°C
—
Rating
Unit
Min.
Max.
—
20
V
—
440*
mW
–55
+125
°C
* : The package is 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
Value
Min.
Typ.
Max.
Unit
Power supply voltage
VCC
—
2.5
6.0
18
V
Reference voltage output
current
IOR
—
–1
—
0
mA
Error amp. input voltage
VIN
—
0
—
VCC – 0.9
V
Control input voltage
VCTL
—
0
—
18
V
Output current
IO
—
3
—
30
mA
Timing capacitance
CT
—
150
—
1500
pF
Timing resistance
RT
—
5.1
—
100
kΩ
Oscillation frequency
fOSC
—
10
200
500
kHz
Soft start capacitance
CS
—
—
0.1
1.0
µF
Short detection capacitance
CSCP
—
—
0.1
1.0
µF
Boot capacitance
CB
—
—
—
0.1
µF
Operating temperature
Ta
—
–40
+25
+85
°C
WARNING: Recommended operating conditions are normal operating ranges for the semiconductor device. All
the device’s electrical characteristics are warranted when operated within these ranges.
Always use semiconductor devices within the recommended operating conditions. 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 representative beforehand.
5
MB3817
■ ELECTRICAL CHARACTERISTICS
(VCC = 6 V, Ta = +25°C)
Symbol
Pin
no.
Condition
VREF
16
∆VREF/
VREF
Input stability
Load stability
Parameter
Output voltage
Output temperature
stability
Reference
section (Ref)
Short circuit output
current
Under voltage
lockout
protection
section (UVLO)
Reset voltage
Unit
Min.
Typ.
Max.
—
1.47
1.50
1.53
V
16
Ta = –40°C to +85°C
—
0.5*
—
%
Line
16
VCC = 2.5 V to 18 V
—
2
10
mV
Load
16
IOR = 0 mA to –1 mA
—
2
10
mV
IOS
16
VREF = 1 V
–10
–5
–2
mA
VTH
13
VCC =
—
2.0
2.3
V
VTL
13
VCC =
1.5
1.8
—
V
VH
13
—
0.1
0.2
—
V
—
Threshold voltage
Hysteresis width
Value
VR
13
0.6
1.0
—
V
VT0
10
Duty cycle = 0 %
0.9
1.0
—
V
VT100
10
Duty cycle = 100 %
—
1.4
1.5
V
VSTB
13
—
—
50
100
mV
Charge current
ICHG
13
—
–1.4
–1.0
–0.6
µA
Threshold voltage
VTH
14
—
0.60
0.65
0.70
V
VSTB
14
—
—
50
100
mV
VI
14
—
—
50
100
mV
Input source current
II
14
—
–1.4
–1.0
–0.6
µA
Oscillator frequency
fOSC
10
CT = 330 pF
RT = 6.2 kΩ
450
500
550
kHz
∆f/fdv
10
VCC = 3.6 V to 16 V
—
1
10
%
∆f/fdt
10
Ta = –40°C to +85°C
—
1*
—
%
Threshold voltage
Soft start section
Input standby
(CS)
voltage
Input standby
Short circuit
detection section voltage
(SCP)
Input latch voltage
Triangular
waveform
Frequency voltage
oscillator section stability
(OSC)
Frequency
temperature stability
* : Standard design value.
(Continued)
6
MB3817
(Continued)
(VCC = 6 V, Ta = +25°C)
Parameter
Output section
(OUT)
Control section
(CTL)
Value
Min.
Typ.
Max.
Unit
3, 4 VFB = 1.2 V
—
—
10
mV
Input offset current
IIO
3, 4 VFB = 1.2 V
—
—
100
nA
Input bias current
II
3, 4 VFB = 1.2 V
–200
–100
—
nA
0
—
VCC – 0.9
V
VCM
3, 4
CMRR
5
DC
60
100
—
dB
Voltage gain
AV
5
DC
60
100
—
dB
Frequency
bandwidth
BW
5
AV = 0 dB
—
800*
—
kHz
VOM+
5
—
1.8
2.0
—
V
VOM–
5
—
—
50
500
mV
Output sink current
IO+
5
VFB = 1.2 V
60
120
—
µA
Output source
current
IO–
5
VFB = 1.2 V
—
–2.0
–0.6
mA
Common mode
rejection ratio
—
VT0
10
Duty cycle = 0 %
0.9
1.0
—
V
VT100
10
Duty cycle = 100 %
—
1.4
1.5
V
ON duty cycle
Dtr
10
VDTC = VREF × 0.88
CT = 330 pF,
RT = 6.2 kΩ
70
80
90
%
Input current
IDTC
6
VDTC = 0 V
–500
–250
—
nA
VT0
10
Duty cycle = 0 %
0.9
1.0
—
V
VT100
10
Duty cycle = 100 %
—
1.4
1.5
V
Input sink current
I
I+
5
—
60
120
—
µA
Input source current
II–
5
—
—
–2.0
–0.6
mA
Output sink current
IO+
10
RE = 15 kΩ
18
30
42
mA
Output source
current
IO–
10
Duty
—
–100
–50
mA
Standby leakage
current
ILO
10
VCC = 18 V,
VO = 18 V
—
—
10
µA
Input on condition
VON
11
—
2.1
—
18
V
Input off condition
VOFF
11
—
0
—
0.7
V
Threshold voltage
PWM
comparator
section (PWM
Comp.)
Condition
VIO
Maximum output
voltage width
Dead time
control section
(DTC)
Pin
no.
Input offset voltage
Common mode input
voltage range
Error amp.
section (Error
Amp.)
Symbol
Threshold voltage
5%
II
15
VCTL = 5 V
—
100
200
µA
Standby current
ICCS
9
VCTL = 0 V
—
—
10
µA
Power supply current
ICC
9
Output “H”
—
2.7
4.0
mA
Input current
* : Standard design value.
7
MB3817
■ TYPICAL CHARACTERISTICS
Power supply current vs. power supply voltage
Reference voltage vs. power supply voltage
5
2.0
Reference voltage VREF (V)
Power supply current ICC (mA)
Ta = +25 °C
4
3
2
1
0
0
2
4
6
8
10
12
14
16
18
Ta = +25 °C
IOR = 0 mA
1.5
1.0
0.5
0.0
20
0
2
4
Power supply voltage VCC (V)
6
8
10
12
14
16
18
20
Power supply voltage VCC (V)
Reference voltage vs. ambient temperature
1.55
VCC = 6 V
IOR = 0 mA
Reference voltage VREF (V)
1.54
1.53
1.52
1.51
1.50
1.49
1.48
1.47
1.46
1.45
−60
−40
−20
0
20
40
60
80
100
Ambient temperature Ta (°C)
Reference voltage vs. control voltage
Control current vs. control voltage
500
Reference voltage VREF (V)
Control current ICTL (µA)
VCC = 6 V
Ta = +25 °C
IOR = 0 mA
1.7
1.6
1.5
1.4
VCC = 6 V
Ta = +25 °C
400
300
200
100
1.3
0
0
1
2
3
Control voltage VCTL (V)
4
5
0
4
8
12
16
20
Control voltage VCTL (V)
(Continued)
8
MB3817
10 M
VCC = 6V
Ta = +25 °C
1M
100 k
CT = 150 pF
10 k
CT = 1500 pF
CT = 15000 pF
1k
1k
10 k
100 k
1M
Timing resistance RT (Ω)
Triangular wave maximum amplitude voltage vs.
timing capacitance
Triangular wave maximum amplitude voltage VCT (V)
Triangular wave frequency fOSC (Hz)
Triangular wave frequency vs.
timing resistance
1.8
1.4
1.2
1.0
0.8
0.6
10
103
104
105
Triangular wave cycle vs. timing capacitance
100
VCC = 6 V
Ta = +25 °C
RT = 6.2 kΩ
VDTC = VREF × 0.88
60
40
20
10 k
100 k
1M
10 M
Triangular wave cycle tOSC (µsec)
1000
80
100
VCC = 6 V
Ta = +25 °C
RT = 6.2 kΩ
10
1
0.1
10
102
Triangular wave frequency fOSC (Hz)
103
104
105
Timing capacitance CT (pF)
Frequency stability vs. ambient temperature
10.00
Frequency stability (%)
Duty Dtr (%)
102
Timing capacitance CT (pF)
Duty vs. triangular wave frequency
0
1k
VCC = 6 V
Ta = +25 °C
RT = 6.2 kΩ
1.6
VCC = 6 V
fOSC = 500 kHz
(CT = 330 pF, RT = 6.2 kΩ)
5.00
0.00
−5.00
−10.00
−60
−40
−20
0
20
40
60
80
100
Ambient temperature Ta (°C)
(Continued)
9
MB3817
(Continued)
Error amp. frequency
50
Ta = +25 °C
40
30
180
VCC = 6 V
135
φ
10
11 kΩ
90
45
Av
0
φ (deg)
20
Av (dB)
• Measurement circuit
225
0
−10
−45
−20
−90
−30
−135
−40
−180
−50
1k
240 kΩ
− +
2.4 kΩ
4 −
10 µF
5
3 +
VREF
11 kΩ
Error Amp.
−225
10 k
100 k
1M
10 M
Frequency fOSC (Hz)
1.0
500
VCC = 6 V
Ta = +25 °C
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0
−10
−20
−30
−40
Output current setting pin current IE (mA)
10
Power dissipation vs. ambient temperature
Power dissipation PD (mW)
Output current setting pin voltage VE (V)
Output current setting pin voltage vs.
output current setting pin current
−50
440
400
300
200
100
0
−40
−20
0
20
40
60
80
Ambient temperature Ta (°C)
100
120
MB3817
■ FUNCTIONAL DESCRIPTION
1. Switching Regulator Functions
(1) Reference voltage circuit (Ref)
The reference voltage circuit generates a temperature-compensated stable voltage (.=.1.50 V). This reference
voltage is used as the reference voltage and bias level for the power control unit.
(2) Triangular-wave oscillator circuit
By connecting a timing capacitor and a resistor to the CT (pin1) and the RT (pin2) terminals, it is possible to
generate any desired triangular oscillation waveform.
(3) Error amplifier
The error amp. is an amplifier circuit that detects the output voltage from the switching regulator and produces
the PWM control signal. The broad in-phase input voltage range of 0 V to Vcc – 0.9 V provides easy setting
from external power supplies and enables use with applications such as DC motor speed control systems.
Also, it is possible to provide stable phase compensation for a system by setting up any desired level of loop
gain, by connecting feedback resistance and a capacitor between the error amp. output pin (FB pin (pin 5))
and the inverse input pin (–IN pin (pin 4)).
(4) PWM comparator (PWM Comp.)
This is a voltage comparator with one inverted input and three non-inverted inputs, and operates as a voltagepulse width modulator controlling output duty in relation to input voltage.
The output transistor is turned on during the interval in which the triangular waveform is lower than any of three
voltages: the error amp. output voltage (FB pin (pin 5)), soft start set voltage (CS pin (pin 13)), or dwell time
setting voltage (DTC pin (pin 6)).
(5) Output circuits (OUT)
The output circuit has totem pole type configuration, and can drive an external PNP transistor.
The on current value can be set up to a maximum of 30 mA using the resistance (RE) connected to the VE pin
(pin 11).
The off current is set by connecting a bootstrap capacitor CB between the CP1 pin (pin 7) and CP2 pin (pin 8).
2. Power Supply Control Functions
The output is switched on and off according to the voltage level at the CTL pin (pin 15).
CTL pin voltage level
Channel on/off status
L(
0.7 V)
Standby mode*
H(
2.1 V)
Operating mode
* : Supply current in standby mode is 10 µA or less.
3. Protective Circuit Functions
(1) Soft start and short protection circuits (CS, SCP)
Soft starting, by preventing a rush current at power-on, can be provided by connecting a capacitor CS to the
CS pin (pin 13).
After the soft start operation is completed, the CSCP pin (pin 14) is held at “L” level (standby voltage VSTB),
which functions as short detection standby mode. If an output short causes the error amp. output to rise above
1.5 V, capacitor CSCP begins charging, and after reaching threshold voltage VTH of 0.65 V causes the OUT pin
(pin 10) to be fixed at “H” level and the dwell time to be set to 100%, and the CSCP pin (pin 14) is held at “L” level.
Once the protection circuit has been activated, the power supply must be reset to restore operation.
11
MB3817
(2) Low input voltage error prevention circuit (UVLO)
Power-on surges and momentary drops in power supply voltage can cause errors in control IC operation, which
can destroy or damage systems. The low input voltage error protection circuit compares the supply voltage to
the internal reference voltage, and sets the OUT pin (pin 10) to “H” level in the event of a drop in supply voltage.
Operation is restored when the power supply voltage returns above the threshold voltage of the low input
voltage error prevention circuit.
12
MB3817
■ SETTING OUTPUT VOLTAGE
• Output voltage VO is plus
V0+
R1
Error Amp.
−IN
4
−
3
+
+IN
R2
V0+ =
VREF
R2
(R1 + R2)
VREF
• Output voltage VO is minus
VREF
R2
R
Error Amp.
−IN
4
−
3
+
+IN
R1
V0− = −
VREF
2 × R2
(R1 + R2) + VREF
R
V0−
13
MB3817
■ METHOD OF SETTING THE OUTPUT CURRENT
The output circuit is comprised of a totem-pole configuration. Its output current waveform is such that the ONcurrent value is set by constant current and the OFF-current value is set by a time constant. These output
currents are set using the equations below.
ON current: IO+ [mA] .=.
500 (Voltage on output current-setting pin VE = 0.5 V)
RE [Ω]
OFF current: OFF-current time constant = proportional to the value of CB
• Output circuit
CB1
CB
7
8
CB2
Outside putting PNP transistor
9
OFF current
setting
block
Q4
VCC
OFF
current
10
Q6
Q5
D1
(0.5 V)
OUT
ON current
11
RE
VE
• Output current waveform
Output current
ON current
0
OFF current
t
14
MB3817
• Voltage and current waveforms on output pin
VCC = 3 V
4
VO (V)
2
0
−2
−4
20
0
IO (mA)
40
−20
0
2
4
6
8
10
t (µs)
• Measuring circuit diagram
7
8
9
CB1
CB
1000 pF
CB2
VCC
VCC
2S81121S
U1FWJ44N
(5.0 V)
OUT
RE 22 µF
VE 16 Ω
VO
35 kΩ
10
22 µF
15 kΩ
11
Pin 4
15
MB3817
■ METHOD OF SETTING THE SHORT DETECTION TIME
The error amp. output is connected to the inverted input of the short detector comparator circuit (SCP Comp.),
where it is constantly compared to the reference voltage of approximately 1.5 V that is connected to the noninverted input.
If the switching regulator load conditions are stabilized, the short detector comparator output is at “H” level,
transistor Q3 is on, and the CSCP pin (pin14) holds the input standby voltage VSTB which is 50 mV.
If load conditions change rapidly due to a cause such as a load short, so that output voltage falls, the short
detector comparator circuit output changes to “L” level. When this happens, transistor Q3 turns off and the short
detector capacitor CSCP connected externally to the CSCP pin starts charging from the input source current II,
which is –1.0 µA.
Short detection time (tPE)
tPE [s] .=. 0.65 × CSCP [µF]
When the short detector capacitor CSCP has been charged to the threshold voltage VTH, which is 0.65 V, the SR
latch is set, and the external PNP transistor is turned off (setting dwell time to 100%). At this time, the SR latch
input is closed, and the CSCP pin is set to input latch voltage VI which is 50 mV.
• Short protection circuit
FB
5
−IN
+IN
4
−
3
+
Outside putting
PNP transistor
Error Amp.
+
+
+
−
PWM Comp.
9
OFF current
setting
block
VCC
Q4
10
OUT
Q6
−
Q5
SCP Comp.
+
1.5 V
1µ
bias
RS
Latch
UVLO
Q2
Q3
14
CSCP
16
D1
(0.5V)
RE
11
VE
MB3817
■ TREATMENT WHEN NOT USING CSCP
When you do not use the timer/latch-actuated short-circuiting protection circuit, connect the CSCP terminal (pin
14) to GND.
• Treatment when not using CSCP
14
CSCP
17
MB3817
■ METHOD OF SETTING SOFT START TIME
To protect against surge currents when the IC is turned on, a soft start setting can be made by connecting a
soft start capacitor (CS) to the CS pin (pin 13).
When the IC starts up (CTL pin (pin 15) to “H” level, Vcc UVLO threshold voltage VTH) the transistor Q1 turns
off and the soft start capacitor (CS) connected to the CS pin begins charging from the charge current ICHG which
is –1.0 µA.
At this time, if the CS pin voltage is less than 0.9 V, the soft start comparator circuit output goes to “H” level,
transistor Q2 turns on and the CSCP pin (pin 14) holds input standby voltage VSTB which is 50 mV so that the
short protection circuit is not activated. When the CS pin voltage is greater than or equal to 0.9 V, transistor Q2
turns off, the PWM comparator circuit compares the CS pin voltage with the triangular wave and changes the
ON duty of the OUTPUT pin, thus achieving a soft start. Note that the soft start time is determined by the following
formula.
Soft start time (time before output ON duty reaches 50%)
tS [ms] .=. 1.2 × CS [µF]
• Soft start circuit
Outside putting
PNP transistor
+
+
+
−
PWM Comp.
9
OFF current
setting
block
VCC
Q4
10
OUT
1µ
Q6
CS
13
Q5
Q1
−
Soft Start Comp.
+
(0.9 V)
1µ
bias
RS
Latch
UVLO
Q2
Q3
14
CSCP
18
D1
(0.5V)
RE
11
VE
MB3817
■ TREATMENT WHEN NOT USING CS
When not using the soft start function, the CS pin (pin 13) should be left open.
• When no soft start time is set
Open
13 CS
19
MB3817
■ METHOD OF SETTING THE DEAD TIME
When the device is set for step-up inverted output based on the flyback method, the output transistor is fixed to
a full-on state (ON-duty = 100 %) at power switch-on. To prevent this problem, you may determine the voltages
on the DTC terminals (pin 6) from the VREF voltage so you can easily set the output transistor’s dead time
(maximum ON-duty) independently for each channel as shown below.
When the voltage on the DTC terminals (pin 6) is lower than the triangular-wave output voltage from the oscillator,
the output transistor turns off. The dead time calculation formula assuming that triangular-wave amplitude ≅
0.4 V and triangular-wave minimum voltage ≅ 1.4 V is given below.
Duty (ON)MAX .=. Vdt – 1.0 V × 100 [%]
0.4
When you do not use these DTC terminals, connect them to VREF terminal.
• When using DTC to set dead time
16 VREF
Ra
6
Vdt
Rb
• When not using DTC to set dead time
16 VREF
6
20
DTC
DTC
MB3817
■ EQUIVALENT SERIES RESISTOR AND STABILITY OF SMOOTHING CAPACITOR
The equivalent series resistance (ESR) of a smoothing capacitor in a DC/DC converter greatly affects the phase
characteristics of the loop depending on its value.
System stability is improved by ESR because it causes the phase to lead that of the ideal capacitor in highfrequency regions. (See Figures 2 and 3) Conversely, if a low-ESR smoothing capacitor is used, system stability
deteriorates. Therefore, use of a low-ESR semiconductor electrolytic capacitors (ex. OS–CON) or tantalum
capacitors calls for careful attention.
• Figure 1 Basic circuit of stepdown DC/DC converter
L
Tr
RC
V IN
D
RL
C
• Figure 2 Gain-Frequency characteristic
• Figure 3 Phase-Frequency characteristic
0
20
−20
−40
−60
10
(2)
(1) : RC = 0 Ω
(2) : RC = 31 mΩ
100
(1)
1k
10 k
Frequency f (Hz)
Phase φ (deg)
Gain AV (dB)
0
(2)
−90
−180
100 k
10
(1) : RC = 0 Ω
(2) : RC = 31 mΩ
100
(1)
1k
10 k
100 k
Frequency f (Hz)
21
MB3817
(Reference Data)
The phase margin is halved by changing the smoothing capacitor from an aluminium electrolytic capacitor (RC
~ 1.0 Ω) to a small-ESR semiconductor electrolytic capacitor (OS – CON; RC ~ 0.2 Ω). (See Figure 5 and 6.)
• Figure 4 DC/DC converter AV – φ characteristic measuring circuit
VOUT
VO +
CNF
AV − φ characteristic
between this interval
−
FB
+
−IN
VIN
+IN
R2
R1
VREF
Error amp.
• Figure 5 Gain-Frequency characteristic
Gain - frequency and phase frequency characteristics of Al electrolytic capacitor (DC/DC converter +5 V output)
60
VCC = 10 V
RL = 25 Ω
CP = 0.1 µF
AV
180
VO
φ
20
90
62 °
0
0
−90
−20
−40
10
100
1k
Phase φ (deg)
Gain AV (dB)
40
+
+ Al electrolytic capacitor
220 µF (16 V)
− RC ≅ 1.0 Ω : FOSC = 1 kHz
GND
−180
100 k
10 k
Frequency f (Hz)
• Figure 6 Phase-Frequency characteristic
Gain - frequency and phase frequency characteristics of OS − CON (DC/DC converter +5 V output)
60
VCC = 10 V
RL = 25 Ω
CP = 0.1 µF
AV
VO
20
90
φ
27 °
0
−20
−40
10
0
−90
100
1k
Frequency f (Hz)
22
180
10 k
−180
100 k
Phase φ (deg)
Gain AV (dB)
40
+
+ OS − CON
22 µF (16 V)
− RC ≅ 0.2 Ω : fOSC = 1 kHz
GND
VIN
13
1000 pF
0.1 µF
CS
6
DTC
15 kΩ
10 kΩ
5
0.047 µF
4
−IN
3
+IN
FB
18 kΩ
1
CT
OSC
Q1
CS
1µ
+
−
2
RT
6.2 kΩ
1.0 V
1.4 V
(0.9 V)
+
+
−
1.5 V
RS
Latch
bias
Soft Start
Comp.
−
Error Amp1
UVLO
SCP
Comp.
+
+
+
−
11
10
9
VE
47 Ω
OUT 22 µF
VCC
CB2
CB1
1000 pF
22 µH
4.7 µF
VO
(3.3 V)
15 Ω
2SB1121S: SANYO Electric Co., Ltd.
UIFWJ44N: TOSHIBA CORPORATION
U1FWJ44N
22 µF
2SB1121S
CTL
15 (note)
Output ON/OFF signal
ON : CTL = 5 V
OFF : CTL = 0 V
12
GND
VCC
Power
ON/OFF
1.5 V
Ref
bias
14
16
CSCP VREF
Q3
SCP
1µ
Q6
Q4
(0.5 V)
OFF current
setting
block
Q5
OUT
0.1 µF
Q2
PWM
Comp.
8
7
MB3817
■ APPLICATION EXAMPLE
1. Step-down scheme
23
24
VIN
15 kΩ
18 kΩ
CS
13
6
1000 pF
0.1 µF
10 kΩ
DTC
5
0.047 µF
4
−IN
3
+IN
FB
1
CT
OSC
Q1
CS
1µ
+
−
2
RT
6.2 kΩ
1.0 V
RS
Latch
bias
1.5 V
(0.9 V)
1.4 V
+
−
+
Soft Start
Comp.
−
Error Amp1
UVLO
SCP
Comp.
+
+
+
−
Q5
VCC
12
9
15
11
10
GND
Power
ON/OFF
1.5 V
Ref
bias
Q6
(0.5 V)
OFF current
setting
block
14
16
CSCP VREF
Q3
SCP
1µ
0.1 µF
Q2
PWM
Comp.
OUT
8
7
22 µF
4.7 µF
VO
(3.3 V)
15 Ω
2SB1121S: SANYO Electric Co., Ltd.
UIFWJ44N: TOSHIBA CORPORATION
U1FWJ44N
22 µH
2SB1121S 4.7 µF 22 µH
(note)
Output ON/OFF signal
ON : CTL = 5 V
OFF : CTL = 0 V
CTL
VE
47 Ω
OUT 22 µF
VCC
CB2
CB1
1000 pF
MB3817
2. Zeta scheme
VIN
15 kΩ
35 kΩ
R2
+IN
−IN
FB
6
3
4
5
1 µF
13
+
CS
CT
OSC
Q1
1µ
1
1000 pF
CS
13 kΩ
1.2 kΩ DTC
0.047 µF
R1
2
6.2 kΩ
RT
1.5 V
(0.9 V)
−1.0 V
RS
Latch
bias
+
+
−1.4 V
−
Soft Start
−
Comp.
Error Amp.
UVLO
SCP
Comp.
+
+
+
−
bias
VCC
D1
(0.5 V)
Q6
Q4
12
9
8
7
15
11
10
GND
Power
Ref
(1.5 V) ON/OFF
Q5
OFF current
setting
block
14
16
CSCP VREF
Q3
1µ
SCP
2.2 µF
Q2
PWM
Comp.
OUT
1000 pF
22 µF
VO
(5.0 V)
2SB1121S: SANYO Electric Co., Ltd.
UIFWJ44N: TOSHIBA CORPORATION
22 µF
2SB1121S U1FWJ44N
CTL
(note)
Output ON/OFF signal
ON : CTL = 5 V
OFF : CTL = 0 V
VE
OUT 22 µF
RE
16 Ω
VCC
CB2
CB1
CB
MB3817
3. Flyback scheme
25
MB3817
■ USAGE PRECAUTIONS
1. Never use setting exceeding maximum rated conditions.
Exceeding maximum rated conditions may cause permanent damage to the LSI.
Also, it is recommended that recommended operating conditions be observed in normal use.
Exceeding recommended operating conditions may adversely affect LSI reliability.
2. Use this device within recommended operating conditions.
Recommended operating conditions are values within which normal LSI operation is warranted.
Standard electrical characteristics are warranted within the range of recommended operating conditions and
within the listed conditions for each parameter.
3. Printed circuit board ground lines should be set up with consideration for common
impedance.
4. Take appropriate static electricity measures.
•
•
•
•
26
Containers for semiconductor materials should have anti-static protection or be made of conductive material.
After mounting, printed circuit boards should be stored and shipped in conductive bags or containers.
Work platforms, tools, and instruments should be properly grounded.
Working personnel should be grounded with resistance of 250 kΩ to 1 MΩ between body and ground.
MB3817
■ ORDERING INFORMATION
Part number
MB3817PFV
Package
Remarks
16-pin Plastic SSOP
(FPT-16P-M05)
27
MB3817
■ PACKAGE DIMENSION
16-pin Plastic SSOP
(FPT-16P-M05)
*: These dimensions do not include resin protrusion.
+0.20
* 5.00±0.10(.197±.004)
1.25 –0.10
+.008
.049 –.004
(Mounting height)
0.10(.004)
INDEX
* 4.40±0.10
(.173±.004)
0.65±0.12
(.0256±.0047)
4.55(.179)REF
C
28
1994 FUJITSU LIMITED F16013S-2C-4
+0.10
6.40±0.20
(.252±.008)
5.40(.213)
NOM
"A"
+0.05
0.22 –0.05
0.15 –0.02
+.004
–.002
.006 –.001
.009
Details of "A" part
+.002
0.10±0.10(.004±.004)
(STAND OFF)
0
10°
0.50±0.20
(.020±.008)
Dimensions in mm (inches)
MB3817
FUJITSU LIMITED
For further information please contact:
Japan
FUJITSU LIMITED
Corporate Global Business Support Division
Electronic Devices
KAWASAKI PLANT, 4-1-1, Kamikodanaka
Nakahara-ku, Kawasaki-shi
Kanagawa 211-8588, Japan
Tel: 81(44) 754-3763
Fax: 81(44) 754-3329
http://www.fujitsu.co.jp/
North and South America
FUJITSU MICROELECTRONICS, INC.
Semiconductor Division
3545 North First Street
San Jose, CA 95134-1804, USA
Tel: (408) 922-9000
Fax: (408) 922-9179
Customer Response Center
Mon. - Fri.: 7 am - 5 pm (PST)
Tel: (800) 866-8608
Fax: (408) 922-9179
http://www.fujitsumicro.com/
Europe
FUJITSU MIKROELEKTRONIK GmbH
Am Siebenstein 6-10
D-63303 Dreieich-Buchschlag
Germany
Tel: (06103) 690-0
Fax: (06103) 690-122
http://www.fujitsu-ede.com/
Asia Pacific
FUJITSU MICROELECTRONICS ASIA PTE LTD
#05-08, 151 Lorong Chuan
New Tech Park
Singapore 556741
Tel: (65) 281-0770
Fax: (65) 281-0220
http://www.fmap.com.sg/
F9812
 FUJITSU LIMITED Printed in Japan
All Rights Reserved.
The contents of this document are subject to change without
notice. Customers are advised to consult with FUJITSU sales
representatives before ordering.
The information and circuit diagrams in this document are
presented as examples of semiconductor device applications,
and are not intended to be incorporated in devices for actual use.
Also, FUJITSU is unable to assume responsibility for
infringement of any patent rights or other rights of third parties
arising from the use of this information or circuit diagrams.
FUJITSU semiconductor devices are intended for use in
standard applications (computers, office automation and other
office equipment, industrial, communications, and measurement
equipment, personal or household devices, etc.).
CAUTION:
Customers considering the use of our products in special
applications where failure or abnormal operation may directly
affect human lives or cause physical injury or property damage,
or where extremely high levels of reliability are demanded (such
as aerospace systems, atomic energy controls, sea floor
repeaters, vehicle operating controls, medical devices for life
support, etc.) are requested to consult with FUJITSU sales
representatives before such use. The company will not be
responsible for damages arising from such use without prior
approval.
Any semiconductor devices have an inherent chance of
failure. You must protect against injury, damage or loss from
such failures by incorporating safety design measures into your
facility and equipment such as redundancy, fire protection, and
prevention of over-current levels and other abnormal operating
conditions.
If any products described in this document represent goods or
technologies subject to certain restrictions on export under the
Foreign Exchange and Foreign Trade Law of Japan, the prior
authorization by Japanese government will be required for
export of those products from Japan.
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