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FUJITSU SEMICONDUCTOR DATA SHEET
DS04-27203-6E
ASSP
Switching Regulator Controller
MB3778
s DESCRIPTION
The MB3778 is a dual switching regulator control IC. It has a two-channel basic circuit that controls PWM system switching regulator power. Complete synchronization is achieved by using the same oscillator output wave. This IC can accept any two of the following types of output voltage: step-down, step-up, or voltage inversion (inverting voltage can be output to only one circuit). The MB3778's low power consumption makes it ideal for use in portable equipment.
s FEATURES
* * * * * * * * Wide input voltage range : 3.6 V to 18 V Low current consumption : 1.7 mA typ. operation, 10 A max. stand-by Wide oscillation frequency range:1 kHz to 500 kHz Built-in timer latch short-circuit protection circuit Built-in under-voltage lockout circuit Built-in 2.46 V reference voltage circuit : 1.23 V output can be obtained from RT terminal Variable dead-time provides control over total range Built-in stand-by function: power on/off function
s PACKAGES
16-pin, Plastic DIP 16-pin, Plastic SSOP
v
16-pin, Plastic SOP
(DIP-16P-M04)
(FPT-16P-M05)
(FPT-16P-M06)
MB3778
s PIN ASSIGNMENT
(TOP VIEW)
CT RT +IN1 -IN1 FB1 DTC1 OUT1 E/GND
1 2 3 4 5 6 7 8
16 15 14 13 12 11 10 9
VREF SCP CTL -IN2 FB2 DTC2 OUT2 VCC
(DIP-16P-M04) (FPT-16P-M05) (FPT-16P-M06)
2
MB3778
s PIN DESCRIPTION
No. 1 2 3 4 5 Pin CT RT +IN1 -IN1 FB1 Function Oscillator timing capacitor terminal (150 pF to 15,000 pF) . Oscillator timing resistor terminal (5.1 k to 100 k) . VREF x 1/2 voltage is also available at this pin for error amplifier reference input. Error amplifier 1 non-inverted input terminal. Error amplifier 1 inverted input terminal. Error amplifier 1 output terminal. A resistor and a capacitor are connected between this terminal and the -IN1 terminal to adjust gain and frequency. OUT1 dead-time control terminal. Dead-time control is adjusted by an external resistive divider connected to the VREF pin. A capacitor connected between this terminal and GND enables soft-start operation. Open collector output terminal. Output transistor has common ground independent of signal ground. This output can source or sink up to 50 mA. Power supply terminal (3.6 to 18 V) Open collector output terminal. Output transistor has common ground independent of signal ground. This output can source or sink up to 50 mA. Sets the dead-time of OUT2. The use of this terminal is the same as that of DTC1. Error amplifier 2 output terminal. Sets the gain and adjusts the frequency when a resistor and a capacitor are connected between this terminal and the -IN2 terminal. Voltage of VREF x 1/2 voltage is internally connected to the non-inverted input of error amplifier 2. Uses error amplifier 2 for positive voltage output. Error amplifier 2 inverted input terminal. Power control terminal. The IC is set in the stand-by state when this terminal is set "Low." Current consumption is 10 A or lower in the stand-by state. The input can be driven by TTL or CMOS. The time constant setting capacitor connection terminal of the timer latch short-circuit protection circuit. Connects a capacitor between this pin and GND. For details, see "How to set time constant for timer latch short-circuit protection circuit". 2.46 V reference voltage output terminal which can be obtained up to 1 mA. This pin is used to set the reference input and idle period of the error amplifiers.
6
DTC1
7 8 9 10
OUT1
E/GND Ground terminal. VCC OUT2
11
DTC2
12
FB2
13
-IN2 CTL
14
15
SCP
16
VREF
3
MB3778
s BLOCK DIAGRAM
9 2.46 V 16 14 1.9 V 1.3 V - + + PWM Comp1 - - + S.C.P. Comp - + + PWM Comp2 OUT2 10 1 2 1.23 V Reference Voltage 2.46 V Error Amp 1 + - Power Supply Control Triangular Oscillator OUT1
7
3 4 5 12 13
2.1 V Error Amp 2 - + 1.23 V 2.46 V 1 A
15 RS Latch R U. V. L. O. - - + 1.1 V 6 11
8
D.T.C. Comp.
4
MB3778
s OPERATION DESCRIPTION
1. Reference voltage circuit
The reference voltage circuit generates a temperature-compensated reference voltage ( = 2.46 V) from VCC (pin : 9) . The reference voltage is used as an operation power supply for internal circuit. The reference is obtained from the VREF terminal (pin 16).
2. Triangular wave oscillator
Triangular waveforms can be generated at any frequency by connecting a timing capacitor and resistor to the CT terminal (pin 1) and to the RT terminal (pin 2) . The amplitude of this waveform is from 1.3 V to 1.9 V. These waveforms are connected to the non-inverting inputs of the PWM comparator and can be output through the CT terminal.
3. Error amplifiers (Error Amp.)
The error amplifier detects the output voltage of the switching regulator and outputs PWM control signals.The in-phase input voltage range is from 1.05 V to 1.45 V.The reference voltage obtained by dividing the reference voltage output (recommended value : VREF/2) or the RT terminal voltage (1.23 V) is supplied to the non-inverting input. The VREF/2 voltage is internally connected to non-inverting input of the other error amplifier. Any loop gain can be chosen by connecting the feedback resistor and capacitor to the inverting input terminal from the output terminal of the error amplifier.Stable phase compensation is possible.
4. Timer latch short circuit protection circuit
This circuit detects the output levels of each error amplifier. If the output level of one or both of the error amplifiers is 2.1 V or higher, the timer circuit begins charging the externally connected protection enable-capacitor. If the output level of the error amplifier does not drop below the normal voltage range before the capacitor voltage reaches the transistor base-emitter voltage, VBE( = 0.65 V), the latch circuit turns the output drive transistor off : and sets the idle period to 100%.
5. Under voltage lock-out circuit
The transition state at power-on or a momentary drops in supply voltage may cause the control IC to malfunction, which may adversely affect or even destroy the system. The under voltage lockout circuit monitors VCC with reference to the internal reference voltage and resets the latch circuit to turn the output drive transistor off. The idle period is set to 100%. It also pulls the SCP terminal (pin 15) "Low".
6. PWM comparator unit
Each PWM comparator has one inverting input and two non-inverting inputs. This voltage-to-pulse-width converter controls the turning on time of the output pulse according to the input voltage. The PWM comparator turns the output drive transistor on while triangular waveforms from the oscillator are lower than the error amplifier output and the DTC terminal voltage.
7. Output drive transistor
The output drive transistors have open collector outputs with common source supply and common grounds independent of VCC and signal ground. The output drive transistors for switching can sink or source up to 50 mA.
8. Power control unit
The power control terminal (pin 14) controls power on/off modes(the power supply current in stand-by mode is 10 A or lower).
5
MB3778
s ABSOLUTE MAXIMUM RATINGS (See NOTE)
(Ta = 25 C) Parameter Power Supply Voltage Error Amp. Input Voltage Control Input Voltage Collector Output Voltage Collector Output Current Power Dissipation Operating Temperature Storage Temperature Symbol VCC VIN VCTL VOUT IOUT PD Top Tstg Condition Ta +25 C (SOP) Ta +25 C (SSOP) Ta +25 C (DIP) Rating Min. -0.3 -0.3 -30 -55 Max. 20 +10 +20 20 75 620* 444* +85 +125
1 2
Unit V V V V mA mW mW mW C C
1000
*1: The packages are mounted on the epoxy board (4 cm x 4 cm) *2: The packages are mounted on the epoxy board (10 cm x 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.
s RECOMMENDED OPERATING CONDITIONS
Parameter Power Supply Voltage Error Amp. Input Voltage Control Input Voltage Collector Output Voltage Collector Output Current Timing Capacitor Timing Resistor Oscillator Frequency Operating Temperature Symbol VCC VIN VCTL VOUT IOUT CT RT fOSC Top Value Min. 3.6 1.05 0 0.3 150 5.1 1 -30 Typ. 6.0 25 Max. 18 1.45 18 18 50 15000 100 500 85 Unit V V V V mA pF k kHz 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
MB3778
s ELECTRICAL CHARACTERISTICS
(Ta = 25 C, VCC = 6 V) Parameter Reference Block Output Voltage Output Temp. Stability Input Stability Load Stability Short Circuit Output Current VREF VRTC Line Load IOS VtH VtL VHYS VR VtPC VSTB VIN Ibpc VtC fOSC fdev fdV fdT Ibdt Idt Vdt Vdt = 2.5 V Idt = 100 A No pull up No pull up Pin 5, Pin 12 CT = 330 pF, RT = 15 k CT = 330 pF, RT = 15 k VCC = 3.6 V to 18 V Ta = -30 C to +85 C IOR = -1 mA Ta = -30 C to +85 C VCC = 3.6 V to 18 V IOR = -0.1 mA to -1 mA VREF = 2 V IOR = -0.1 mA IOR = -0.1 mA IOR = -0.1 mA 2.41 -2 -30 80 1.5 0.60 -1.4 160 -4 150 2.46 0.2 2 1 -10 2.72 2.60 120 1.9 0.65 50 50 -1.0 2.1 200 5 1 0.2 500 2.51 2 10 7.5 -3 0.70 100 100 -0.6 240 +4 1 0.3 V % mV mV mA V V mV V V mV mV A V kHz % % % A A V Symbol Condition Value Min. Typ. Max. Unit
Under Voltage Lockout Protection Block Threshold Voltage Hysteresis Width Reset Voltage (VCC) Protection Circuit Block (S.C.P.) Input Thresold Voltage Input Stand by Voltage Input Latch Voltage Input Source Current Comparator Threshold Voltage Triangular Waveform Oscillator Block Oscillator Frequency Frequency Deviation Frequency Stability (VCC) Frequency Stability (Ta) Dead-Time Control Block (D.T.C.) Input Bias Current Latch Mode Sink Current Latch Input Voltage
7
MB3778
s ELECTRICAL CHARACTERISTICS (Continued)
(Ta = 25 C, VCC = 6 V) Parameter Error Amp. Block Input Offset Voltage Input Offset Current Input Bias Current Common Mode Input Voltage Range Voltage Gain Frequency Band Width Common Mode Rejection Ratio Max. Output Voltage Width Output Sink Current Output Source Current PWM Comparator Block Input Threshold Voltage (fOSC = 10 kHz) On duty Cycle Input Sink Current Input Source Current Control Block Input Off Condition Input On Condition Control Terminal Current Output Block Output Leak Current Output Saturation Voltage All Device Block Stand-by Current Average Supply Current ICCS ICCa VCTL = 0 V VCTL = VCC, No Output Load 1.7 10 2.4 A mA Leak VSAT VO = 18 V IO = 50 mA 1.1 10 1.4 A V VOFF VON ICTL VCTL = 10 V 2.1 200 0.7 400 V V A Vt100 Vt0 Dtr IIN+ IIN- Duty Cycle = 100% Duty Cycle = 0% Vdt = VREF/1.45 Pin 5, Pin 12 = 1.6 V Pin 5, Pin 12 = 1.6 V 1.05 55 1.9 1.3 65 1.0 -60 2.25 75 V V % mA A VIO IIO IB VICR AV BW CMRR VOM+ VOM- IOM+ IOM- VO = 1.6 VO = 1.6 VO = 1.6 V VO = 1.6 V VO = 1.6 V VCC = 3.6 V to 18 V RNF = 200 k AV = 0 dB -6 -100 -500 1.05 70 60 VREF - 0.3 -100 80 1.0 80 0.7 1.0 -60 6 100 1.45 0.9 mV nA nA V dB MHz dB V V mA A Symbol Condition Value Min. Typ. Max. Unit
8
MB3778
s TEST CIRCUIT
CTL TEST SW 4.7 k CPE OUTPUT 1 4.7 k OUTPUT 2 16 15 14 13 12 11 10 9 INPUT VCC = 6 V
MB3778 1 2 3 4 5 6 7 8
330 pF
15 k
TEST INPUT
s TIMING CHART (Internal Waveform)
Triangular waveform oscillator output Short circuit protection comparator Reference 2.1 V 1.9 V input 1.6 V Dead Time, PWM input voltage 1.3 V Error Amp. output PWM comparator output Output Transistor collector waveform S.C.P. Terminal waveform Short circuit protection comparator output Control Terminal voltage
"High" "Low" "High" "Low" 0.65 V 0.05 V "High" "Low" Power "ON" 2.1 V (VCTL : Min. Value) 0V 3.6 V (VCC : Min. Value) 0V Power "OFF" tPE DEAD TIME 100%
Power supply voltage
Protection Enable Time tPE
0.6 x 106 x CPE (s)
9
MB3778
s APPLICATION CIRCUIT
* Chopper Type Step Down/inverting
CTL VIN (10 V)
820 pF 1 8.2 k 2 1.8 k 3 4.7 k 150 k 4 MB3778 5 12 13 150 k 0.033 F 10 k 6 -+ 1 F 7 10 11 +- 1 F 220 F -+ 14 1.8 k 15 16 0.1 F 56 H
4.7 k
0.033 F
4.7 k
10 k
8
9
5.6 k 2.4 k
330 330 330 120 H 120 H -+ 220 F VO+ ( 5 V) 330
-+ 9.1 k VO- ( -5 V) 220 F
GND
10
MB3778
* Chopper Type Step Up/Inverting
CTL VIN (5 V)
820 pF 1 8.2 k 2 1.8 k 3 4.7 k 150 k 4 MB3778 5 12 13 150 k 0.033 F 10 k 6 -+ 1 F 7 10 11 +- 1 F 220 F -+ 14 1.8 k 15 16 0.1 F 56 H
4.7 k 0.033 F 4.7 k
10 k
8
9 16 k
4.7 k
330 3.9 k
330
120 H 100
120 H
220 F -+ 9.1 k VO- ( -5 V)
220 F +-
GND
VO+ ( 5 V)
11
MB3778
* Multi Output Type (Apply Transformer)
CTL VIN (10 V)
820 pF 1 8.2 k 2 15 16 0.1 F 56 H
3
14 1.8 k
4 MB3778 5
13 150 k 0.033 F 10 k 220 F -+
12
6
11
7
10
8
9 1.8 k
4.7 k
220
1000 pF 5.6 k
-+ 220 F
-+ 220 F
-+ 220 F
-+ 220 F
VO2- ( -12 V)
VO1- ( -5 V)
GND
VO2+ ( 5 V)
VO1+ ( 12 V)
12
MB3778
s HOW TO SET THE OUTPUT VOLTAGE
The output voltage is set using the connections shown in "Connection of error Amp. Output Voltage V0 0" and "Connection of Error Amp. Output Voltage V0 < 0". The error amplifier power is supplied by the reference voltage circuit as is that of the other internal circuits. The common mode input voltage range is from 1.05 V to 1.45 V. Set 1.23 V (VREF/2) as the reference input voltage that is connected to either inverting or non-inverting input terminals. * Connection of Error Amp. Output Voltage V0 0
VREF
VO+
R
R1 +
VO + =
VREF 2 x R2
(R1 + R2)
PIN 5 or PIN 12 - R R2 RNF
* Connection of Error Amp. Output Voltage V0 < 0
VREF
VO- = -
VREF 2 x R1
(R1 + R2) + VREF
R
R1 + PIN 5 -
R
R2
RNF
VO-
13
MB3778
s HOW TO SET TIME CONSTANT FOR TIMER LATCH SHORT-CIRCUIT PROTECTION CIRCUIT
Below Figure shows the configuration of the protection latch circuit. Each error amplifier output is connected to the inverting inputs of the short-circuit protection comparator and is always compared with the reference voltage (2.1 V) connected to the non-inverting input. When the load condition of the switching regulator is stable, the error amplifier has no output fluctuation. Thus, short-circuit protection control is also kept in balance, and the SCP terminal (pin 15) voltage is held at about 50 mV. If the load changes drastically due to a load short-circuit and if the inverting inputs of the short-circuit protection comparator go above 2.1 V, the short-circuit protection comparator output goes "Low" to turn off transistor Q1. The SCP terminal voltage is discharged, and then the short-circuit protection comparator charges the protection enable capacitor CPE according to the following formula : VPE = 50 mV + tPE x 10 - 6 / CPE 0.65 = 50 mV + tPE x 10 - 6 / CPE CPE = tPE / 0.6 (F) When the protection enable capacitor is charged to about 0.65 V, the protection latch is set to enable the under voltage lockout circuit and the output drive transistor is turned off. The idle period is also set to 100% at the same time. Once the under voltage lockout circuit is enabled, the protection enable is released; however, the protection latch is not reset if the power is not turned off. The inverting inputs (pin 6 or 11) of the D.T.C. comparator are compared to the reference voltage (about 1.1 V) connected to the non-inverting input. To prevent malfunction of the short-circuit protection-circuit when the soft-start operation is done by using the DTC terminal, the D.T.C. comparator outputs a "High" level while the DTC terminal goes up to about 1.1 V, and then closes the SCP terminal by turning transistor Q2 on. * Protection Latch Circuit
2.46 V 1 A S.C.P. Comp. R1 Error Amp. 1 Error Amp. 2 2.1 V - - + 15 CPE Q1 Q2 Q3 SR Latch U.V.L.O.
- - + D.T.C. Comp. 1.1 V
6 11
DTC1 DTC2
14
MB3778
s SETTING THE IDLE PERIOD
When voltage step-up, fly-back step-up or inverted output are set, the voltage at the FB terminal may go higher than the triangular wave voltage due to load fluctuation, etc. In this case the output transistor will be in full-on state(ON duty 100%). This can be prevented by setting the maximum duty for the output transistor. This is done by setting the DTC1 terminal (pin 6) voltage using resistance division of the VREF voltage as illustrated below. When the DTC1 terminal voltage is higher than the triangular waveform voltage, the output transistor is turned on. If the triangular waveform amplitude specified by the maximum duty calculation formula is 0.6 V, and the lower voltage limit of the triangular waveform is 1.3 V, the formula would be as follows (other channels are similar) : Duty (ON) max (%) = (Vdt - 1.3 V) / 0.6 V x 100, Vdt (V) = Rb / (Ra + Rb) x VREF : Also, if no output duty setting is required, the voltage should be set greater than the upper limit voltage of the triangular waveform, which is 1.9 V. * Setting the idle time at DTC1 (DTC2 is similar)
VREF 16 Ra DTC1 6 Rb Vdt
15
MB3778
s SETTING THE SOFT START TIME
When power is switched on, the current begins charging the capacitor (CDTC1) connected the DTC1 terminal (pin 6). The soft start process operates by comparing the soft start setting voltage, which is proportional to the DTC1 terminal voltage, with the triangular waveform, and varying the ON-duty of the OUT terminal (pin 7). The soft start time until the ON duty reaches 50% is determined by the following equation: Soft start time (time until output ON duty = 50%) . ts (s) = - CDTC1 x Ra x Rb / (Ra + Rb) x ln (1 - 1.6 (Ra + Rb) / (2.46 Rb) ) : For example, if Ra = 4.7 k and Rb = 10 k, the result is: ts (s) = 0.1 x CDTC1 (F) : * Soft Start on DCT1 terminal (DTC2 is similar)
VREF 16 Ra DTC1 6 Rb CDTC1
16
MB3778
s USING THE RT TERMINAL
The triangular waves, as shown in Figure "No VREF/2 connection to external circuits from RT terminal", act to set the oscillator frequency by charging and discharging the capacitor connected to the CT terminal using the current value of the resistor connected to the RT terminal. In addition, when voltage level VREF/2 is output to external circuits from the RT terminal, care must be taken in making the external circuit connections to adjust for the fact that I1 is increased by the value of the current I2 to the external circuits in determining the oscillator frequency (see Figure "VREF/2 connection to external circuits from RT terminal"). * No VREF/2 connection to external circuits from RT terminal
Triangular wave oscillator ICT = IRT = VREF 2RT
( VREF ) 2
2 IRT RT CT 1 ICT
* VREF/2 connection to external circuits from RT terminal
Triangular wave oscillator
ICT = IRT = I1 + I2 VREF = + I2 2RT
( VREF ) 2
2 IRT To external circuits I2 I1 RT CT 1 ICT
17
MB3778
s SYNCHRONIZATION OF ICs
A fixed condenser and resistor are inserted in the CT and RT terminals of IC which becomes a master when synchronizing by using plurality of MB3778. As a result, the slave ICs oscillate automatically. The RT terminals (pin 2) of the slave ICs are connected to the VREF terminal (pin 16) to disable the charge/discharge circuit for triangular wave oscillation. The CT terminals of the master and slave ICs are connected together. * Connection of Master, Slave
MB3778 (MASTER)
VCC
CT
RT
MB3778 (SLAVE)
MB3778 (SLAVE)
18
MB3778
s TYPICAL CHARACTERISTICS
Power supply voltage vs. Reference voltage
Average supply current ICCa (mA) 5.0 Reference voltage VREF (V) Ta = +25 C 2.0
Power supply voltage vs. Average supply current
Ta = +25 C
2.5
1.0
0 0 4 8 12 16 20 Power supply voltage VCC (V)
0 0 4 8 12 16 20 Power supply voltage VCC (V)
Reference voltage vs. Temperature
VCC = VCTL = 6 V IOR = -1 mA Triangular waveform Upper / Lower Limit voltage (V) 2.47 2.46 Reference voltage VREF (V) 2.45 2.44 2.43 2.42 2.41 2.40 -40
Timing capacitor vs. Triangular waveform Upper/Lower Limit voltage
2.2 2.0 1.8 1.6 1.4 1.2
Upper limit
Lower limit
1.0 0.8 102 103 Timing capacitor CT (pF)
VCC = 6 V RT = 15 k Ta = +25 C 104
-20
0
20
40
60
80
100
Temperature Ta (C)
Collector saturation voltage vs. Sink Current
Error Amp. Max. output voltage (V) 5.0 Collector saturation voltage (V) VCC = 6 V Ta = +25 C 4.0 3.0
Error Amp. Max. output voltage vs. Frequency
VCC = 6 V Ta = +25 C 2.0
3.0
1.0
2.0
1.0
0 100
500 1 k
5 k 10 k Frequency (Hz)
50 k 100 k
500 k
0 0 100 200 300 400 Sink current (mA) 500
19
MB3778
(Continued)
Timing resistor vs. Oscillation frequency
VCC = 6 V Ta = +25 C Triangular waveform cycle (s)
Triangular waveform cycle vs. Timing capacitor
100
VCC = 6 V RT = 15 k Ta = +25 C
Oscillation frequency fOSC (Hz)
1M
10
100 k CT = 150 pF
10 k
CT = 1500 pF
1 102 103 104 Timing capacitor CT (pF) 105
CT = 15000 pF 1k 1k 5 k 10 k 50 k100 k Timing resistor RT () 500 k
Temperature vs. Frequency stability
10 Frequency stability fdT (%) VCC = 6 V CT = 330 pF RT = 15 k Duty Dtr (%) 100 80 60 40 20 -10 -40 -20 0 20 40 60 80 100 120 0
Oscillation frequency vs. Duty
VCC = 6 V CT = 330 pF RT = 15 k Ta = +25 C
0
5k
10 k
50 k 100 k Oscillation frequency (Hz)
500 k 1 M
Temperature Ta (C)
Control voltage vs. Reference voltage
Reference voltage VREF (V) 5.0 VCC = 6 V Ta = +25 C Control current ICTL (A) 500
Control input current
VCC = 6 V Ta = +25 C
2.5
250
0
0
1
2
3
4
5
0
0
4
Control voltage VCTL (V)
8 12 16 Control voltage ICTL (V)
20
20
MB3778
(Continued)
Frequency vs. Gain/Phase Frequency vs. Gain/Phase (Actual Data)
180 90 0 40 AV Phase (deg) Phase (deg) Phase (deg) Gain AV (dB) Gain AV (dB) 20 0 -20 -40 10 100 1k 10 k 100 k 20 0 -20 -40 10 100 1k 10 k Frequency f (Hz) 100 k 90 0 CNF = 0.047 F 180
40
CNF = OPEN AV
-90
-90
-180 1M
-180 1M
Frequency f (Hz)
Frequency vs. Gain/Phase (Actual Data)
CNF = 470 pF 40 Phase (deg) 20 0 -20 -40 10
Frequency vs. Gain/Phase (Actual Data)
CNF = 4700 pF AV 90 0 180
40 20 0
180 90 0 -90 -180
Gain AV (dB)
AV
Gain AV (dB)
-20 -40 10 100
-90 -180
1k 10 k Frequency f (Hz)
100 k
1M
100
1k 10 k Frequency f (Hz)
100 k
1M
Actual Circuit
VREF VREF CNF
4.7 k 4.7 k - 10 F -+ 4.7 k 4.7 k OUT + Error Amp. 240 k
IN
21
MB3778
(Continued)
Power Dissipation vs. Ambient Temperature (SOP)
700 500 620 600 500 400 300 200 100 0 -40 -20 0 20 40 60 80 100 444 400 300 200 100 0 -40
Power Dissipation vs. Ambient Temperature (SSOP)
Power dissipation PD (mW)
Power dissipation PD (mW)
-20
0
20
40
60
80
100
Ambient temperature Ta (C)
Ambient temperature Ta (C)
Power Dissipation vs. Ambient Temperature (DIP)
1100 1000 900 800 700 600 500 400 300 200 100 0 -40 -20 0 20 40 60 Ambient temperature Ta (C) 80 100
22
Power dissipation PD (mW)
MB3778
s APPLICATION
1. Equivalent series resistor and stability of smoothing capacitor
The equivalent series resistor (ESR) of the smoothing capacitor in the DC/DC converter greatly affects the loop phase characteristic. The stability of the system is improved so that the phase characteristic may advance the phase to the ideal capacitor by ESR in the high frequency region (see "Gain vs. Frequency" and "Phase vs. Frequency"). A smoothing capacitor with a low ESR reduces system stability. Use care when using low ESR electrolytic capacitors (OS CONTM) and tantalum capacitors. Note: OS CON is the trademark of Sanyo Electnic Co., Ltd. DC/DC Converter Basic Circuit
Tr
L
RC VIN D C RL
Gain vs. Frequency
Phase vs. Frequency
20
0
Phase (deg)
Gain AV (dB)
0 -20 -40 -60 10
(2) -90
(2)
(1) : RC = 0 (2) : RC = 31 m 100
(1) 100 k
-180 10
(1) : RC = 0 (2) : RC = 31 m
(1)
1k 10 k Frequency f (Hz)
100
1k 10 k Frequency f (Hz)
100 k
23
MB3778
Reference data If an aluminum electrolytic smoothing capacitor (RC 1.0 ) is replaced with a low ESR electrolytic capacitor(OS CONTM : RC 0.2 ), the phase margin is reduced by half(see Fig. 37 and 38). DC/DC Converter AV vs. characteristic Test Circuit
VOUT VO+
CNF
AV vs. characteristic Between these points - + -IN +IN R1 VIN R2
FB
VREF/2 Error Amp.
DC/DC Converter +5 V output Gain vs. Phase
60 40 AV Gain AV (dB) 20 0 -20 -40 10 62 VCC = 10 V RL = 25 CP = 0.1 F
180 90 0 -90 Phase (deg)
VO+ + - AI Capacitor 220 F (16 V) RC 1.0 : fOSC = 1 kHz GND
100
1k
10 k
-180 100 k
Figure 38
60 AV 40 Gain AV (dB) 20
DC/DC Converter +5 V output Gain vs. Phase
VCC = 10 V RL = 25 CP = 0.1 F
180 90 Phase (deg)
VO+ + - OS CONTM 22 F (16 V) RC 0.2 : fOSC = 1 kHz GND
0 -20 -40 10 27 0
-90 -180 100 k
100
1k Frequency f (Hz)
10 k
24
MB3778
s ORDERING INFORMATION
Part number MB3778P MB3778PFV MB3778PF Package 16-pin Plastic DIP (DIP-16P-M04) 16-pin Plastic SSOP (FPT-16P-M05) 16-pin Plastic SOP (FPT-16P-M06) Remarks
25
MB3778
s PACKAGES DIMENSION
16-pin, Plastic DIP (DIP-16P-M04)
19.55 -0.30 .770
+.008 -.012 +0.20
INDEX-1 INDEX-2 6.200.25 (.244.010)
4.36(.172)MAX
0.51(.020)MIN 0.250.05 (.010.002)
3.00(.118)MIN
0.460.08 (.018.003)
+0.30 +.012 -0 +0.30 +.012 -0
0.99 -0 .039 1.27(.050) MAX
1.52 -0
.060 2.54(.100) TYP
7.62(.300) TYP
15MAX
C
1994 FUJITSU LIMITED D16033S-2C-3
Dimensions in mm (inches) .
(Continued)
26
MB3778
(Continued) 16-pin, Plastic SSOP (FPT-16P-M05)
* 5.000.10(.197.004)
16 9
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 8
+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 F16013S-3C-5
Dimensions in mm (inches) . (Continued)
27
MB3778
(Continued) 16-pin, Plastic SOP (FPT-16P-M06)
2.25(.089)MAX 10.15
+0.25 -0.20
.400
+.010 -.008
0.05(.002)MIN (STAND OFF)
INDEX
5.300.30 (.209.012) "B"
7.800.40 (.307.016)
6.80 -0.20 +.016 .268 -.008
+0.40
1.27(.050) TYP
0.450.10 (.018.004)
O0.13(.005)
M
0.15 -0.02 +.002 .006 -.001 Details of "A" part 0.40(.016)
+0.05
0.500.20 (.020.008)
Details of "B" part 0.15(.006) 0.20(.008)
"A" 0.10(.004) 8.89(.350)REF
0.20(.008) 0.18(.007)MAX 0.68(.027)MAX 0.18(.007)MAX 0.68(.027)MAX
C
1994 FUJITSU LIMITED F16015S-2C-4
Dimensions in mm (inches) .
28
MB3778
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.
F0012 (c) FUJITSU LIMITED Printed in Japan

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