MB3882

Manufacturer Part NumberMB3882
Description2-channel DC/DC Converter IC with Synchronous Rectifier
ManufacturerFujitsu Media Devices
MB3882 datasheet
 


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FUJITSU SEMICONDUCTOR
DATA SHEET
ASSP For Power Management Applications
2-channel DC/DC Converter IC
with Synchronous Rectifier
MB3882
DESCRIPTION
The MB3882 is a 2-channel DC/DC converter IC using pulse width modulation (PWM) and synchronous rectifi-
cation, 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.
FEATURES
• Synchronous rectification for high efficiency
• Supply voltage range : 5.5 V to 18 V
• High-precision reference voltage : 2.5 V
• Error Amp. threshold voltage : 1.25 V
• 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
PACKAGE
1
1
(0 C to 85 C)
24-pin Plastic SSOP
(FPT-24P-M03)
DS04-27226-1E

MB3882 Summary of contents

  • Page 1

    ... Synchronous Rectifier MB3882 DESCRIPTION The MB3882 is a 2-channel DC/DC converter IC using pulse width modulation (PWM) and synchronous rectifi- cation, designed for down conversion applications. This device is a power supply with high output drive capacity. Synchronous rectification also provides for high efficiency. ...

  • Page 2

    ... MB3882 PIN ASSIGNMENTS SGND : 3 CS1 : 4 INE1 : 5 FB1 : 6 INC1 : 7 OUT1 VS1 : 9 CB1 : 10 OUT2 PGND : 12 2 (TOP VIEW VREF 23 : VCC 22 : CSCP 21 : CS2 20 : INE2 19 : FB2 18 : INC2 17 : OUT1 VS2 15 : CB2 14 : OUT2 (FPT-24P-M03) ...

  • Page 3

    ... INE2 I CH2 error Amp. inverted input terminal 21 CS2 CH2 soft start capacitor connection terminal. (Also used as channel control) 22 CSCP Timer latch short protection capacitor connection terminal 23 VCC Reference voltage, control circuit power supply terminal 24 VREF O Reference voltage output terminal MB3882 Description 3 ...

  • Page 4

    ... MB3882 BLOCK DIAGRAM 6 FB1 10 A Error Amp.1 5 INE1 4 CS1 1.25 V OVP Comp.1 7 INC1 VCC 1. FB2 10 A Error Amp.2 20 INE2 21 CS2 1.25 V OVP Comp.2 18 INC2 Latch1 VCC R 1. SCP Comp CSCP 4 VCC Reg. PWM Comp.1-1 PWM Comp.2-1 Latch1 PWM Comp.1-2 PWM Comp ...

  • Page 5

    ... 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. Conditions CC CB terminal Duty Duty) OSC 10cm). MB3882 Rating Unit Min. Max 120 mA 800 mA 740 125 C 5 ...

  • Page 6

    ... MB3882 RECOMMENDED OPERATING CONDITIONS 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 ...

  • Page 7

    ... 470 1 TH1 1 TH2 INE MB3882 0 mA, VREF 0 mA Value Unit Min. Typ. Max. 2.475 2.500 2.525 V 0. 4.95 5.05 5 ...

  • Page 8

    ... MB3882 Parameter Symbol Pin No. Frequency band width 7. Output voltage Error Amp Block Output source I [Error Amp.] current Output sink current 8. PWM Threshold Comparator voltage Block [PWM Comp.] 9. Dead time Maximum Adjustment duty cycle Block [DTC] I SOURCE1 Output current (main side) Output voltage (main side) 10 ...

  • Page 9

    ... OPEN OUT2 : OUT1 : 8, 11, 17 470 pF OUT1 OUT2 OPEN OUT1 : OUT2 : 7, 18 INC INC MB3882 0 mA, VREF 0 mA Value Unit Min. Typ. Max. 100 200 ns 100 250 ns 1.44 1.47 1.50 V 200 16 ...

  • Page 10

    ... MB3882 TYPICAL CHARACTERISTICS Supply Current vs. Supply Voltage 15.0 12.5 10.0 7.5 5.0 2.5 0 Supply voltage V Reference Voltage vs. Ambient Temperature 2.0 1.5 1.0 0.5 0.0 0.5 1.0 1.5 2 Ambient temperature Triangular Wave Upper/Lower Limit Voltage vs. Triangular Wave Oscillator Frequency 2.5 2.0 1.5 1.0 0 Triangular wave oscillator frequency fosc (Hz) 10 Reference Voltage vs. Supply Voltage 5 Ta ...

  • Page 11

    ... Ambient temperature 180 90 4 4.7 k 1.5 V 180 10 M MB3882 VCC 12 V CTL 5 V CTL 150 pF CTL 470 pF CTL 15000 100 VCC 470 pF 20 ...

  • Page 12

    ... MB3882 (Continued) 12 Power Dissipation vs. Ambient Temperature 800 740 700 600 500 400 300 200 100 Ambient temperature 100 ...

  • Page 13

    ... 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 the use of low on-resistor FET devices. MB3882 5 ) provides high gate-source capacitor, enabling 13 ...

  • Page 14

    ... MB3882 2. Channel Control Functions Channel ON/OFF control is provided by using the CS1 terminal (pin 4) and CS2 terminal (pin 21) setting functions. CS terminal voltage level CS1 GND GND Hi-Z Hi-Z 3. Protective Functions (1) Timer Latch Short Circuit Protection (SCP) The short circuit protection comparators read the output voltage levels. If the output voltage on either channel falls below the short detection voltage, the timer circuit is activated to start charging the external capacitor Cscp connected to the CSCP terminal (pin 22) ...

  • Page 15

    ... 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 ( mV) . (When a short circuit is detected on either of the two channels, both I channels are shut off.) MB3882 : 0. latch is set, turning the external TH 15 ...

  • Page 16

    ... MB3882 FB1 6 5 INE1 4 CS1 FB2 19 20 INE2 21 CS2 CSCP 22 C SCP Q1 Q4 Timer Latch Short Circuit Protection Circuit 16 Error Amp.1 1.25 V Error Amp.2 1.25 V SCP Comp. 2.1 V bias S R UVLO Latch Drive 8 OUT1-1 11 Drive OUT2-1 17 Drive OUT1-2 14 Drive ...

  • Page 17

    ... PROCESSING WITHOUT USING THE CSCP TERMINAL When the timer latch short circuit protection circuit is not used, the CSCP terminal (pin 22) should be shorted to GND using the shortest possible connection. Operation Without Using the CSCP Terminal 3 GND CSCP 22 MB3882 17 ...

  • Page 18

    ... MB3882 SOFT START TIME SETTING The soft start function prevents rush current events when the IC power is turned on, by connecting soft start capacitors ( the CS1 terminal (pin 4) for channel 1, and the CS2 terminal (pin 21) for channel When the IC is activated (Vcc begin charging the externally connected soft start capacitors (Cs Because the error Amp ...

  • Page 19

    ... VREF (FB2) 19 FB1 6 Error ( INE2) 20 Amp. 5 INE1 21 (CS2) 4 CS1 1. (Q3) Soft Start Block MB3882 UVLO 19 ...

  • Page 20

    ... MB3882 PROCESSING WITHOUT USING THE CS TERIMNALS When the soft start function is not used, the CS1 terminal (pin 4) and CS2 terminal (pin 22) should be left open. "Open" OSCILLATOR FREQUENCY SETTING The oscillator frequency can be set by connecting a timing capacitor (C resistor ( the RT terminal (pin 2) . ...

  • Page 21

    ... Comp output goes to “H” level, setting a latch and shutting off the corresponding channel. Each of the overvoltage protection circuit latches operates independently. Detection voltage V ( 1.47 (R3 R4) /R4 OVP Once the protection circuit has been activated, it can be reset by lowering the VCC voltage below the reset voltage (1.7 V min INC2) INC1 R4 VCC 18 OVP R Comp 1.47 V MB3882 Q 21 ...

  • Page 22

    ... MB3882 PRECAUTIONS RELATED TO INTERNAL IC POWER CONSUMPTION The internal power dissipation in the IC is greatly affected by the oscillator frequency and the FET total gate charge. When using the MB 3882 in an application, caution must be taken in relation to internal IC power consumption. As shown below, I (average current) can be determined from the total gate charge Qg ...

  • Page 23

    ... Consumption vs. Input Voltage” on the following page, as well as the “Power dissipation vs. Ambient Temperature.” CB1 Crss Crss 1 2 OUT1 Ciss 1 VS1 Ciss 2 OUT2-1 11 PGND 12 T Bias current Ibias1 Bias current Ibias2 MB3882 ...

  • Page 24

    ... MB3882 Power Consumption vs. Input Voltage (Qg Parameters) 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00 Power Consumption vs. Input Voltage (fosc Parameters) 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0. 200 kHz OSC SW1 OFF SW2 OFF Input voltage Vin (V) ...

  • Page 25

    ... APPLICATION CIRCUIT MB3882 25 ...

  • Page 26

    ... MB3882 COMPONENT LIST COMPONENT ITEM FET D1, D2 Diode D3, D4 Diode L1, L2 Coil C1 Ceramics Condenser C2 Ceramics Condenser C3 Ceramics Condenser C4 Ceramics Condenser C5 Ceramics Condenser C6, C7 Ceramics Condenser C8 Electrolytic Condenser C9 Ceramics Condenser C10 OS Condenser C11 Electrolytic Condenser C12 Ceramics Condenser C13 Ceramics Condenser ...

  • Page 27

    ... REFERENCE DATA Conversion Efficiency vs. Load Current Characteristics (Channel 1) 100 output SW1 OFF SW2 Load current IL (A) MB3882 Vin 6 V Vin 8.5 V Vin ...

  • Page 28

    ... Persons handling semiconductors should be grounded directly with resistance of 250 k • Do not apply negative voltages. • Application of negative voltage of 0 greater can create parasitic transistor effects on an LSI device, leading to abnormal operation. ORDERING INFORMATION Part Number MB3882PFV 28 Package Plastic SSOP 24-pin (FPT-24P-M03 ...

  • Page 29

    ... NOM "A" +0.10 +0.05 0.22 0.15 Ð0.05 Ð0.02 +.004 +.002 .009 .006 Ð.002 Ð.001 MB3882 Details of "A" part 0.10±0.10(.004±.004) (STAND OFF) 0 10¡ 0.50±0.20 (.020±.008) Dimensions in mm (inches ...

  • Page 30

    ... MB3882 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. 3545 North First Street, San Jose, CA 95134-1804, U ...