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FUJITSU SEMICONDUCTOR DATA SHEET
DS04-27227-1E
ASSP For Power Management Applications
1-channel DC/DC Converter IC
with Synchronous Rectifier
MB3885
s DESCRIPTION
The MB3885 is a 1-channel DC/DC converter IC using pulse width modulation (PWM) and synchronous rectification, designed for down conversion applications. This device is a power supply with high output drive capacity. Synchronous rectification also provides for high efficiency. In addition, a 5 V regulator is built in to reduce the number of system components. The result is an ideal built-in power supply for driving products with high speed CPU's such as home TV game devices and notebook PC's.
s FEATURES
* * * * * * * Synchronous rectification for high efficiency Supply voltage range : 5.5 V to 18 V Built-in high-precision reference voltage circuit : 2.5 V 1% Error Amp. threshold voltage : 1.25 V 1% (0 C to 85 C) Oscillator frequency range : 10 kHz to 500 kHz Built-in soft start circuit with error Amp. input control Totem pole type output for N-ch MOSFET
s PACKAGE
20-pin Plastic SSOP
(FPT-20P-M03)
MB3885
s PIN ASSIGNMENTS
(TOP VIEW)
N.C. : 1 N.C. : 2 CSCP : 3 CT : 4 RT : 5 CS : 6 FB : 7 -INE : 8 +INE : 9 VCC : 10
20 : N.C. 19 : N.C. 18 : VREF 17 : SGND 16 : PGND 15 : OUT2 14 : VS 13 : OUT1 12 : CB 11 : VB
(FPT-20P-M03)
2
MB3885
s PIN DESCRIPTIONS
Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Symbol N.C. N.C. CSCP CT RT CS FB -INE +INC VCC VB CB OUT1 VS OUT2 PGND SGND VREF N.C. N.C. I/O O I I O O O O No connection No connection Timer latch short protection capacitor connection terminal Triangular wave oscillator frequency setting capacitor connection terminal Triangular wave oscillator frequency setting resistor connection terminal Soft start capacitor connection terminal (Also used as output control) Error Amp. output terminal Error Amp. inverted input terminal Overvoltage comparator non-inverted input terminal Reference voltage, control circuit power supply terminal Output circuit bias output terminal Output bootstrap terminal Insert a capacitor between the CB and VS terminals, to bootstrap the IC internal output transistor. Totem pole output terminal (External main side FET gate drive) External main side FET source connection terminal Totem pole output terminal. (External synchronous rectifier side FET gate drive) Ground terminal Ground terminal Reference voltage output terminal No connection No connection Description
3
MB3885
s BLOCK DIAGRAM
VCC 10 5 V Reg. 11 VB
FB 7
10 A Error Amp. - + + 1.25 V OVP Comp. PWM Comp.1 + + - PWM Comp.2 + Latch R SQ - Drive2
12 CB
-INE 8 CS 6
DTC
Drive1
13 OUT1 14 VS
+INC 9
+ - VCC 1.47 V
15 OUT2 16 PGND
SCP Comp. 1 A
- + 2.1 V bias S R Latch
1.9 V 1.3 V
CSCP 3
bias Ref (2.5 V) 18 VREF
VCC
UVLO
OSC
Power
4 CT
5 RT
17 SGND
4
MB3885
s ABSOLUTE MAXIMUM RATINGS
Parameter Supply voltage Boot voltage Output current Peak output current Power dissipation Storage temperature Symbol VCC VCB IO IOP PD Tstg Conditions CB terminal Duty 5% (t = 1 / fOSC x Duty) Ta +25 C Rating Min. -55 Max. 20 25 120 800 555* +125 Unit V V mA mA mW C
* : The package is mounted on the dual-sided epoxy board (10cm x 10cm). 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.
5
MB3885
s RECOMMENDED OPERATING CONDITIONS
Value Min. 5.5 -1 -1 0 0 -100 -700 10 6.8 150 1.0 -30 Typ. 12 200 10 470 0.1 0.1 4.7 0.1 0.01 +25 Max. 18 23 0 0 VCC - 1.8 VCC 100 700 500 12 15000 1.0 1.0 10 1 0.1 +85
Parameter Supply voltage Boot voltage Reference voltage output current Bias output current Input voltage Output current Peak output current Oscillator frequency Timing resistor Timing capacitor Boot capacitor Reference voltage output capacitor Bias output capacitor Soft start capacitor Short detection capacitor Operating ambient temperature
Symbol VCC VCB IOR IOB VIN VINC IO IOP fOSC RT CT CB CREF CVB CS CSCP Ta
Conditions CB terminal VREF terminal VB terminal -INE terminal +INC terminal Duty 5% (t = 1 / fosc x Duty) VREF terminal VB terminal
Unit V V mA mA V V mA mA kHz k pF F F F F F 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.
6
MB3885
s ELECTRICAL CHARACTERISTICS
(VCC = 12 V, VB = 0 mA, VREF = 0 mA, Ta = +25 C) Parameter Symbol Pin No. VREF Output voltage 1. Reference Input stability Voltage Block Load stability [Ref] Short output current 2. Bias Voltage Block [VB] 3. Undervoltage Lockout Circuit Block [UVLO] 4. Soft Start Block [CS] 5. Short Detection Comparator Block [SCP] 6. Triangular Wave Oscillator Block [OSC] VREF/ VREF Line Load Ios 18 18 18 18 18 Conditions Ta = +25 C Ta = 0 C to +85 C VCC = 5.5 V to 18 V VREF = 0 mA to -1 mA VREF = 2 V Value Min. 2.475 -28 Typ. 2.500 0.5* 1 3 -14 Max. 2.525 10 10 -7 Unit V % mV mV mA
Output voltage
VB
11
4.95
5.05
5.15
V
Threshold voltage Hysteresis width Reset voltage Charge current Threshold voltage Input source current Short detection time Oscillator frequency Frequency temperature variation rate
VTH VH VRST
10 10 10
VCC =
2.6 1.7 -14
2.9 0.2* 2.1 -10
3.2 2.5 -6
V V V A
ICS
6
VTH ICSCP tSCP fOSC fOSC/ fOSC VTH1 VTH2 IB AV
3 3 3 4
CSCP = 0.01 F RT = 10 k, CT = 470 pF
0.63 -1.4 4.5 170
0.68 -1.0 6.8 190
0.73 -0.6 12.2 210
V A ms kHz
4
Ta = 0 C to +85 C FB = 1.6 V, Ta = +25 C FB = 1.6 V, Ta = 0 C to +85 C -INE = 0 V DC
1*
%
7. Error Amp Block [Error Amp.]
Threshold voltage Input bias current Voltage gain
8 8 8 7
1.241 1.2375 -200 60
1.2500 1.2500 -20 100
1.259 1.2625
V V nA dB
* : Standard design value
(Continued)
7
MB3885
(VCC = 12 V, VB = 0 mA, VREF = 0 mA, Ta = +25 C) Parameter Frequency band width 7. Error Amp Block [Error Amp.] Output voltage Output source current Output sink current 8. PWM Comparator Threshold Block voltage [PWM Comp.1, PWM Comp.2] 9. Dead time Adjustment Block [DTC] Symbol Pin No. BW VFBH VFBL ISOURCE ISINK 7 7 7 7 7 FB = 1.6 V FB = 1.6 V Duty cycle = 0% Conditions AV = 0 dB Value Min. 2.2 1.5 Typ. 800* 2.5 0.8 -100 9.0 Max. 1.0 -45 Unit kHz V V A mA
VTL
7
1.2
1.3
V
VTH
7
Duty cycle = Dtr
1.81
2.0
V
Maximum duty cycle
Dtr
13
RT = 10 k, CT = 470 pF Duty 5% (t = 1 / fOSC x Duty) Duty 5% (t = 1 / fOSC x Duty) OUT1 = -100 mA, CB = 17 V, VS = 12 V OUT1 = 100 mA, CB = 17 V, VS = 12 V Duty 5% (t = 1 / fOSC x Duty) Duty 5% (t = 1 / fOSC x Duty) OUT2 = -100 mA OUT2 = 100 mA VB = 10 mA
85
90
95
%
Output current (main side)
ISOURCE1 ISINK1 VOH1 VOL1
13 13 13 13 15 15 15 15 12
CB - 2.5 2.5
-700* 900* CB - 0.9 VS + 0.9 -750* 900* 4.1 1.0 0.9
VS + 1.4 1.4 1.1
mA mA V V mA mA V V V
Output voltage (main side) 10. Output Block [Drive]
Output current ISOURCE2 (synchronous rectifier side) ISINK2 Output voltage (synchronous rectifier side) Diode voltage VOH2 VOL2 VD
* : Standard design value
(Continued)
8
MB3885
(Continued)
(VCC = 12 V, VB = 0 mA, VREF = 0 mA, Ta = +25 C) Symbol Pin No. Conditions RT = 10 k, CT = 470 pF OUT1 = OUT2 = OPEN, VS = 0 V OUT2 : - OUT1 : RT = 10 k, CT = 470 pF OUT1 = OUT2 = OPEN, VS = 0 V OUT1 : - OUT2 : +INC = Value Min. Typ. Max. Unit
Parameter
tD1 10. Output Block [Drive] Dead time tD2 13, 15
100
200
ns
100
250
ns
11. Overvoltage Detection Comparator Block [OVP] 12. General
Threshold voltage Input bias current Power supply current
VTH
9
1.44
1.47
1.50
V
IB
9
+INC = 0 V
-200
-30
nA
ICC
10
6.5
9.8
mA
9
MB3885
s TYPICAL CHARACTERISTICS
Supply Current vs. Supply Voltage
10 Reference voltage VREF (V) Ta = +25 C Supply current ICC (mA) 8 6 4 2 0 0 5 10 15 Supply voltage VCC (V) 20 5 4 3 2 1 0 0 5 10 15 Supply voltage VCC (V) 20
Reference Voltage vs. Supply Voltage
Ta = +25 C VREF = 0 mA
Reference Voltage vs. Ambient Temperature
2.0 Reference voltage VREF (%) 1.5 1.0 0.5 0.0 -0.5 -1.0 -1.5 -2.0 -40 -20 0 20 40 60 80 100 VCC = 12 V VREF = 0 mA
Ambient temperature Ta (C)
Triangular wave upper/lower limit voltage VCT (V)
Triangular wave upper/lower limit voltage VCT (V)
Triangular Wave Upper/Lower Limit Voltage vs. Triangular Wave Oscillator Frequency
2.5 Ta = +25 C VCC = 12 V CTL = 5 V Upper limit 1.5
Triangular Wave Upper/Lower Limit Voltage vs. Ambient Temperature
2.5 VCC = 12 V RT = 10 k CT = 470 pF Upper limit 1.5 Lower limit
2.0
2.0
1.0
Lower limit
1.0
0.5 1k
10 k 100 k 1M Triangular wave oscillator frequency fosc (Hz)
0.5 -40
-20
0
20
40
60
80
100
Ambient temperature Ta (C)
(Continued)
10
MB3885
Triangular Wave Oscillator Frequency vs. Timing Capacitor
Triangular wave frequency fOSC (Hz) Ta = +25 C VCC = 12 V CTL = 5 V RT = 10 k Triangular wave frequency fOSC (Hz) 10 M 10 M 1M 100 k
Triangular Wave Oscillator Frequency vs. Timing Resistor
Ta = +25 C VCC = 12 V CTL = 5 V CTL = 150 pF CTL = 470 pF 10 k 1k 100 1k CTL = 15000 pF
1M
100 k
10 k
1k 10
100
1000
10000
100000
Timing capacitor CT (pF)
10 k Timing resistor RT ()
100 k
Triangular Wave Oscillator Frequency vs. Supply Voltage
Triangular wave frequency fOSC (Hz) 240 230 220 210 200 190 180 170 160 150 0 5 10 15 Supply voltage VCC (V) 20 Ta = +25 C RT = 10 k CT = 470 pF Triangular wave frequency fOSC (Hz) 250 250 240 230 220 210 200 190 180 170 160
Triangular Wave Oscillator Frequency vs. Ambient Temperature
VCC = 12 V RT = 10 k CT = 470 pF
150 -40
-20
0 20 40 60 Ambient temperature Ta (C)
80
100
Error Amp Gain, Phase vs. Frequency
40 20 0 -20 -40 1k 10 k 100 k 1M Frequency f (Hz) Ta = +25 C 180 90 0 -90 -180 10 M
VCC = 12 V Phase (deg.) 240 k 4.7 k
- +
Gain AV (dB)
AV
2.4 k 8 6
IN 10 F 4.7 k 1.5 V
- + + 1.25 V
7 OUT Error Amp.
(Continued)
11
MB3885
(Continued)
Power Dissipation vs. Ambient Temperature
600 555 500 400 300 200 100 0 -40
Power dissipation PD (mW)
-20
0 20 40 60 80 Ambient temperature Ta (C)
100
12
MB3885
s FUNCTION DESCRIPTION
1. DC/DC Converter Function
(1) Reference Voltage Block The reference voltage circuit takes the voltage feed from the power supply terminal (pin 10) and generates a temperature compensated reference voltage (2.5 V typ.) , for use as the reference voltage for the power supply control unit. Also, an external load current can be obtained from the power supply at the VREF terminal (pin 18) , up to a maximum of 1 mA. (2) Triangular Wave Oscillator Block A triangular waveform with amplitude 1.3 V to 1.9 V can be generated by connecting a timing capacitor and resistor to the CT terminal (pin 4) and RT terminal (pin 5) , respectively. The triangular oscillator waveform can be input to the IC's internal PWM comparator, as well as supplied externally from the CT terminal. (3) Error Amp Block (Error Amp.) The error Amp. is an amplifier that detects the output voltage from the DC/DC converter and outputs a PWM control signal. The error Amp. has a broad in-phase input voltage range of 0 to Vcc-1.8 V that can be easily set by the external power supply. In addition, an arbitrary loop gain can be set up by connecting a feedback resistor and capacitor between the error Amp. output pin and inverter input pin, providing stable phase compensation to the system. Also, power-on rush current can be prevented by connecting a soft start capacitor between the error Amp. noninverted input pins CS terminal (pin 6) . The soft start function operates with a stable soft start time that is not dependent on the output load of the DC/DC converter. (4) PWM Comparator Block (PWM Comp.) This is a voltage - pulse width modulator that controls the output duty according to the input voltage. Main side : Turns the output FET on in the intervals in which the error Amp. output voltage is higher than the triangular wave voltage. Synchronous rectifier side : Turns the output FET on in the intervals in which the triangular wave voltage the is lower than error Amp. voltage. (5) Output Block The output block has totem pole configuration on both the main side and synchronous rectifier side, and can drive an external N-ch MOSFET. Also, the high output drive capability (700 mA Max. : duty 5%) provides high gate-source capacitor, enabling the use of low on-resistor FET devices.
13
MB3885
2. Control Functions
Output ON/OFF control is provided by using the CS terminal (pin 6) setting functions. Output On/Off Setting Functions CS terminal voltage level Output state GND Hi-Z OFF ON
3. Protective Functions
(1) Timer Latch Short Circuit Protection (SCP) The short circuit protection comparators read the output voltage levels. If the output voltage falls below the short detection voltage, the timer circuit is activated to start charging the external capacitor Cscp connected to the CSCP terminal (pin 3) . When capacitor voltage reaches approximately 0.68 V the output FET turns off, setting the idle interval to 100%. Once the protection circuit is activated, it can be reset by turning the power supply off and on again. (See "Setting the Timer Latch Short Circuit Protector Time Constant.") (2) Undervoltage Lockout Circuit Block (UVLO) Transient status during normal power-on or momentary drops in supply voltage can cause abnormal operation in an control IC, leading to damage or degradation of system components. The undervoltage lockout circuit prevents such abnormal operations by reading the internal reference voltage level and switching the output FET off, setting the idle interval to 100% and holding the CSCP terminal (pin 3) to "L" level. System operation is restored when the supply voltage rises back about the undervoltage lockout circuit threshold voltage. (3) Overvoltage Protection Block (OVP) The overvoltage protection circuit uses an overvoltage comparator (OVP Comp.) to read the output voltage levels from the DC/DC converter. If the output voltage exceeds the threshold voltage a latch is set, turning off the main side FET. Once the protector circuit is activated, it can be reset by switching the power supply off and on again.
14
MB3885
s SETTING THE TIMER LATCH SHORT CIRCUIT PROTECTOR TIME CONSTANT
The error Amp. output level constantly compares operation with the short circuit protection comparator as the reference voltage. When the DC/DC comparator load conditions are stable, the short circuit protection comparator output is at "H" level, transistor Q1 is on, and the CSCP terminal (pin 3) is held at input standby voltage (VSTB : = 50 mV) . If load conditions change rapidly, such as during a load short, causing output voltage to drop, the short circuit protection comparator output goes to "L" level. This causes the transistor Q1 to shut off, charging the short circuit protection capacitor Cscp (connected to the CSCP terminal) at 1 A. Short detection time tscp (s) = 0.68 x Cscp (F) : When the capacitor Cscp is charted to the threshold voltage (VTH : = 0.68 V) a latch is set, turning the external FET off (setting the idle interval to 100%) . At this time the latch input is closed and the CSCP terminal is held at the input latch voltage (VI : = 50 mV) .
10 A FB 7 Error Amp. 13 OUT1
-INE
8
- + +
1.25 V
Drive
CS CS
6
Q2
Drive
15 OUT2
SCP Comp. 1 A
- +
2.1 V
CSCP
bias 3 S R
CSCP
Latch Q1 Q4
UVLO
< Timer Latch Short Circuit Protection Circuit >
15
MB3885
s PROCESSING WITHOUT USING THE CSCP TERMINAL
When the timer latch short circuit protection circuit is not used, the CSCP terminal (pin 3) should be shorted to SGND using the shortest possible connection.
17 SGND
CSCP 3
< Operation Without Using the CSCP Terminal >
16
MB3885
s SOFT START TIME SETTING
The soft start function prevents rush current events when the IC power is turned on, by connecting soft start capacitors (Cs) to the CS terminal (pin 6) . When the IC is activated (Vcc UVLO threshold voltage) , Q2 is off and the CS terminals begin charging the externally connected soft start capacitors (Cs) at 10 A. Because the error Amp. output (FB) is determined by the ratio of the lower of the two non-inverted input terminals (1.25 V, CS terminal voltage) to the inverted input terminal voltage (-INE) , the soft start interval (when CS terminal voltage < 1.25 V) FB is determined by the ratio of the -INE terminal voltage and CS terminal voltage. Thus the DC/DC converter output voltage is in proportion to the rise in the CS terminal voltage as the soft start capacitor connected to the CS terminal charges. The soft start time is determined by the following formula. Soft start time (time to output 100%) ts (s) = 0.125 x Cs (F) :
CS terminal voltage 2.3 V Error. amp block comparison voltage to -INE voltage
1.25 V
0V
Soft start time ts
17
MB3885
VREF
10 A
10 A
FB -INE
7 8
- + +
1.25 V Q2
Error Amp.
CS CS
6
UVLO
< Soft Start Block
>
18
MB3885
s PROCESSING WITHOUT USING THE CS TERMINALS
When the soft start function is not used, the CS terminal (pin 6) should be left open.
"Open" CS
< Operation Without Soft Start Setting >
s OSCILLATOR FREQUENCY SETTING
The oscillator frequency can be set by connecting a timing capacitor (CT) to the CT terminal (pin 4) and a timing resistor (RT) to the RT terminal (pin 5) . Oscillator frequency 893000 fosc (kHz) = CT (pF) *RT (k) :
s OUTPUT VOLTAGE SETTING
VO FB R1 -INE R2 CS 6 1.25 V 8 7 VO = Error Amp. 1.25 V R2
(R1 + R2)
- + +
19
MB3885
s OVERVOLTAGE PROTECTION CIRCUIT VOTAGE SETTING
Overvoltage conditions in the DC/DC converter output voltage can be detected by connecting external resistance from the DC/DC converter output voltage to the +INC terminal (pin 9) on the respective overvoltage protection comparator circuits (OVP comp.) . When the output voltage of the DC/DC converter rises above the detection voltage, the overvoltage protection comparator (OVP Comp.) output goes to "H" level, setting a latch and shutting off. Detection voltage VOVP (V) = 1.47 x (R3 + R4) /R4 : Once the protection circuit has been activated, it can be reset by lowering the VCC voltage below the reset voltage (1.7 V Min.) .
VO VCC R3 +INC1 R4 9
+ -
1.47 V
OVP Comp.
R S
Q
20
MB3885
s PRECAUTIONS RELATED TO SUPPLY VOLTAGE RANGE
Although the supply voltage range listed under recommended operating requirements is 5.5V-18V, generation of heat limits the maximum operating supply voltage since the IC's internal loss varies with the frequency of oscillation and FET's total gate charge. When using the MB 3885 in an application, caution must be taken in relation to supply voltage range. As shown below, IB (average current) can be determined from the total gate charge Qg1, Qg2, charged from the gate capacitance (Ciss1, Ciss2, Crss1, Crss2) of the external FET Q1, Q2, by the following formula. IB (A) = I1 + I2 = Ibias1 x T1 Qg1 T2 Qg2 + + Ibias2 x + T T T T (Ibias1 = Ibias2 = 2 mA) :
Because IC current consumption other than IB is 6.5 mA, power consumption can be determined from the following formula. Power consumption : Pc Pc (W) = 0.0065 x VCC + VCC x IB - 1 / 2 x VB x IB :
21
MB3885
Vin
VCC 10 5V
IB 11
VB CVB CB Q1 OUT1 VS Ciss2 Crss1 Ciss1 Crss2 Q2 A L1 VO1
12 I1 Drive 1 I2 Drive 2 13 14
15 16
OUT2 PGND
T VOUT1
VOUT2
I1 T1 I2 T2
Bias current Ibias1 2 mA
Bias current Ibias2 2 mA
t
Using the above formulas to determine power consumption, settings should be made with reference to the "Power Consumption vs. Input Voltage" on the following page, as well as the "Power dissipation vs. Ambient Temperature."
22
MB3885
Power Consumption vs. Input Voltage (Qg Parameters)
1.00 Power consumption PC (W) 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Input voltage Vin (V) Qg1 = Qg2 = 70 nC Qg1 = Qg2 = 50 nC Qg1 = Qg2 = 30 nC Qg1 = Qg2 = 20 nC Qg1 = Qg2 = 10 nC Ta = +25 C fOSC = 200 kHz SW1 = OFF
Power Consumption vs. Input Voltage (fosc Parameters)
1.00 Power consumption PC (W) 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 fOSC = 500 kHz fOSC = 300 kHz fOSC = 200 kHz fOSC = 100 kHz fOSC = 10 kHz Ta = +25 C Qg1 = Qg2 = 20 nC SW1 = OFF
0.00 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Input voltage Vin (V)
23
24
MB3885
s APPLICATION CIRCUIT
Vin 10
C12 0.1 F VCC VB 5 V Reg. FB C3 0.022 F R1 R6 2 k 2.7 k -INE R3 10 k 7 11 D2 10 A Error Amp. - + + OVP Comp. + - Latch VCC R SQ 1.47 V PWM Comp.1 DTC + + - PWM Comp.2 + - Drive2 OUT1 Drive1 13 VS 14 OUT2 PGND 16 C1 + 22 F C2 0.1 F Q2 D1 C8 CB 4.7 F C9 0.1 F A Q1 L1 2.7 H C10 + 68 F x3 C11 2.2 F Vo (2 V)
12
A Output On/Off signal SW1
R2 3.3 k 0.1 F +INC R5 10 k
8 CS 6 C4 1.25 V 9
R4 6.2 k
15
SCP Comp. 1 A CSCP C5 0.01 F
- + 2.1 V bias S R Latch
1.9 V 1.3 V
3
bias UVLO
VCC
OSC 4 CT C6 470 pF 5 RT
Ref (2.5 V) Power 18 17 VREF SGND C7 0.1 F
R7 10 k
MB3885
s COMPONENT LIST
COMPONENT Q1, Q2 D1 D2 L1 C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 R1 R2 R3 R4 R5 R6 R7 ITEM FET Diode Diode Coil OS Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser Electrolytic Condenser Ceramics Condenser Ceramics Condenser Resistor Resistor Resistor Resistor Resistor Resistor Resistor SPECIFICATION VDS = 30 V, Qg = 23 nC (Max.) VF = 0.35 V (Max.) , at IF = 1 A VF = 0.3 V (Max.) , at IF = 10 mA 2.7 H 22 F 0.1 F 0.022 F 0.1 F 0.01 F 470 pF 0.1 F 4.7 F 0.1 F 68 F 2.2 F 0.1 F 2 k 3.3 k 10 k 6.2 k 10 k 2.7 k 10 k 12 A, 4.5 m 25 V 25 V 25 V 25 V 10 V 50 V 25 V 10 V 25 V 6.3 V 6.3 V 25 V 1/4 W 1/4 W 1/4 W 1/4 W 1/4 W 1/4 W 1/4 W VENDOR IR ROHM ROHM TDK PARTS No. IRF7811 RB051L-40 RB495D RLF12545T -2R7N8R7

Notes : IR : International Rectifier Corp. ROHM : Rohm, Ltd. TDK : TDK, Ltd.
25
MB3885
s REFERENCE DATA
Conversion Efficiency vs. Load Current Characteristics
100 Ta = +25 C 2 V output SW1 = OFF
95 Conversion efficiency (%)
90
85
Vin = 6 V Vin = 8.5 V Vin = 10 V
80
75
70 0 1 2 3 4 5 6 7 8 9 10 Load current IL (A)
26
MB3885
s PRECAUTIONARY INFORMATION
* Printed circuit board ground lines should be designed with consideration for common impedance. * * * * * Take sufficient countermeasures should be taken to protect against static electricity. Always place semiconductors in containers that have anti-static provisions, or are conductive. After mounting, PC boards should be placed in conductive bags or containers for storage and handling. Working surfaces, tools, and measurement equipment should be grounded. Persons handling semiconductors should be grounded directly with resistance of 250 k to 1 M.
* Do not apply negative voltages. * Application of negative voltage of -0.3 V or greater can create parasitic transistor effects on an LSI device, leading to abnormal operation.
s ORDERING INFORMATION
Part Number MB3885PFV Package Plastic SSOP 20-pin (FPT-20P-M03) Remarks
27
MB3885
s PACKAGE DIMENSION
20-pin, Plastic SSOP (FPT-20P-M03)
* 6.500.10(.256.004)
20 11
* Dimensions include resin remainder.
0.170.03 (.007.001)
* 4.400.10
INDEX
6.400.20 (.173.004) (.252.008)
Details of "A" part 1.25 -0.10 .049 -.004 LEAD No.
1 10
+0.20 +.008
(Mounting height)
0.65(.026)
"A" 0.240.08 (.009.003) 0.13(.005)
M
0~8 0.100.10 (Stand off) (.004.004) 0.25(.010)
0.10(.004)
0.500.20 (.020.008) 0.45/0.75 (.018/.030)
C
1999 FUJITSU LIMITED F20012S-3C-5
Dimensions in mm (inches) .
28
MB3885
FUJITSU LIMITED
For further information please contact: Japan FUJITSU LIMITED Corporate Global Business Support Division Electronic Devices Shinjuku Dai-Ichi Seimei Bldg. 7-1, Nishishinjuku 2-chome, Shinjuku-ku, Tokyo 163-0721, Japan Tel: +81-3-5322-3347 Fax: +81-3-5322-3386 http://edevice.fujitsu.com/ North and South America FUJITSU MICROELECTRONICS, INC. 3545 North First Street, San Jose, CA 95134-1804, U.S.A. Tel: +1-408-922-9000 Fax: +1-408-922-9179 Customer Response Center Mon. - Fri.: 7 am - 5 pm (PST) Tel: +1-800-866-8608 Fax: +1-408-922-9179 http://www.fujitsumicro.com/ Europe FUJITSU MICROELECTRONICS EUROPE GmbH Am Siebenstein 6-10, D-63303 Dreieich-Buchschlag, Germany Tel: +49-6103-690-0 Fax: +49-6103-690-122 http://www.fujitsu-fme.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/ Korea FUJITSU MICROELECTRONICS KOREA LTD. 1702 KOSMO TOWER, 1002 Daechi-Dong, Kangnam-Gu,Seoul 135-280 Korea Tel: +82-2-3484-7100 Fax: +82-2-3484-7111
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. The contents of this document may not be reproduced or copied without the permission of FUJITSU LIMITED. FUJITSU semiconductor devices are intended for use in standard applications (computers, office automation and other office equipments, industrial, communications, and measurement equipments, 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 inherently a certain rate 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 Control Law of Japan, the prior authorization by Japanese government should be required for export of those products from Japan.
F0011 (c) FUJITSU LIMITED Printed in Japan

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