MB3871 Fujitsu Microelectronics, Inc., MB3871 Datasheet
MB3871
Related parts for MB3871
MB3871 Summary of contents
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... Mobile Pentium MB3871 DESCRIPTION The FUJITSU MB3871 is a pulse width modulation (PWM) DC/DC converter IC chip that provides a selection of 1 2.0 V output voltages for Mobile Pentium The MB3871 utilizes synchronous rectification for high efficiency and features a soft-start/discharge control function for ease in designing power supplies in multi-supply systems, making it ideal for Mobile Pentium supply systems ...
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... MB3871 PIN ASSIGNMENT SGND : – ENB : 7 OUT1 : OUT2 : 11 PGND : 12 2 (Top view VREF CSCP 21 : PWRGOOD 20 : VSENSE 19 : CTL 18 : TEST 17 : VD3 16 : VD2 15 : VD1 14 : VD0 (FPT-24P-M03) ...
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... Outputs a “H” level signal when the output voltage is within the range from VTLOW to VTHIGH. 22 CSCP — Timer-latch short-circuit protection capacitor connection pin 23 V — Power supply pin for reference power and control circuit CC 24 VREF O Reference voltage output pin MB3871 Descriptions 3 ...
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... MB3871 BLOCK DIAGRAM VSENSE 20 CS Error Amp. –IN 5 – VD0 D/A 15 VD1 (4-bit) 16 VD2 17 VD3 OSC 18 TEST CT (40 pF) 4 PWRGOOD 21 POWERGOOD PWRGD ( 10%) Overvoltage protection (17.5%) OVP PWM Comp DTC – PWM VB Comp.2 + – + – Comp. SCP Comp. + SCP – ...
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... VD0 Output voltage setting (V) 0 2.000 1 1.950 0 1.900 1 1.850 0 1.800 1 1.750 0 1.700 1 1.650 0 1.600 1 1.550 0 1.500 1 1.450 0 1.400 1 1.350 0 1.300 1 0 (output OFF) MB3871 5 ...
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... MB3871 ABSOLUTE MAXIMUM RATINGS Parameter Power supply voltage V Bias voltage V Boot voltage V Control input voltage V PWRGOOD output voltage V Output current I O Peak output current I O Allowable dissipation P Storage temperature Tstg * : When mounted cm-square dual-sided epoxy base board WARNING: Semiconductor devices can be permanently damaged by application of stress (voltage, current, temperature, etc ...
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... PWRGOOD pin — Duty 5% –700 (t = 1/f Duty) OSC — 100 — 51 — — — — — — — — — — — –30 MB3871 Value Unit Typ. Max — — — V – 0 — — ...
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... MB3871 ELECTRICAL CHARACTERISTICS Parameter Output voltage Output voltage temperature regulation Reference voltage block Input stability (Ref) Load stability Short circuit output current Threshold voltage Under voltage lockout circuit Hysteresis voltage block (UVLO) Reset voltage Soft start block Charge current (CS) Threshold voltage ...
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... PWRGOOD = 5 V LEAK V 21 PWRGOOD = Discharge control ON IH Discharge control OFF I 7 ENB = 0 V ENB MB3871 ( Value Unit Min. Typ. Max. 1.2 1.3 — V — 1.86 2 — – 2.5 CB – 1.5 — 1 1.4 — ...
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... MB3871 (Continued) Parameter Threshold voltage Over voltage protection Hysteresis voltage comparator block (OVP) VSENSE pin input current D/A input voltage D/A (VD3 to VD0 D/A input voltage pin) (D/A) Input current Standby current General Power supply current 10 Pin Symbol Condition no VSENSE = , 1 — ...
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... Power supply voltage V Reference voltage, CTL pin current vs. Control voltage 5.0 4.0 3.0 2.0 1.0 80.0 100 5.0 10.0 Control voltage V ERR threshold (2.0 V setting) vs. Temperature characteristics 2. 2.02 2.00 1.98 196 1.94 –40.0 –20.0 0.0 MB3871 8.0 12.0 16.0 20.0 ( +25 C 500 REF 400.0 300.0 I CTL 200.0 100.0 0 15.0 20.0 25.0 (V) CTL = 130 k 20 ...
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... MB3871 (Continued) ERR threshold (1.3 V setting) vs. Temperature characteristics Error Amp. gain, Phase vs. Frequency characteristics –10 –20 –30 – 100 K Frequency 1. 130 k CC 1.32 1.30 1.28 1.26 1.24 –40.0 –20.0 0.0 20.0 40.0 60.0 Temperature +25 C 180 135 B 90 ...
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... Triangular wave oscillator frequency vs. Temperature characteristics 220 210 200 190 180 –40.0 –20.0 Triangular wave oscillator frequency vs. Timing resistance characteristics 1000 100 10 10 Timing resistance ( 130 k CC 0.0 20.0 40.0 60.0 80.0 100.0 Temperature MB3871 100 1000 13 ...
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... MB3871 FUNCTION DESCRIPTION 1. Switching Regulator Function (1) Reference voltage circuit (Ref) The reference voltage circuit uses the voltage supply from the V compensated reference voltage ( 3.5 V) for use as the reference voltage for the internal circuits of the IC chip also possible to supply a reference voltage output external circuits through the VREF pin (pin 24) ...
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... CC Power surges at power-on, or momentary under-voltage situations can cause abnormal operation in the MB3871, which may lead to damage or deterioration in systems. This circuit prevents abnormal operation during times of low voltage by using the supply voltage to detect the level of the internal reference voltage, and fixes output pins OUT1 (pin 8) and OUT2 (pin 11) to “L” level. Once the supply voltage recovers to a level above the threshold voltage of the under voltage lockout circuit, operation is restored ...
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... DC/DC converter. The resulting voltage instability may cause an “L” level from the PWRGOOD block, activating the OVP protection and shutting off the output from the DC/DC converter. To switch VD3 to VD0 pin settings, first input an “L” level control signal to the CTL pin to place the MB3871 in standby status. ...
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... PWRGOOD COMPARATOR CIRCUIT, OVP CIRCUIT OPERATION TIMING CHART CTL signal VD DC/DC VD 0.9 output voltage PWRGOOD signal OUT1 signal OUT2 signal VD 1.175 DC/DC VD 1.1 output voltage VD 0.9 PWRGOOD OUT2 VD 1.175 1.1 Hysteresis voltage 30 mV Hysteresis voltage 30 mV Hysteresis voltage 30 mV MB3871 VD 0.9 Operation when ENB signal is “High”. 17 ...
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... MB3871 CTL LOGIC CIRCUIT OPERATION TIMING CHART CTL signal ENB signal V output voltage REF CS pin voltage DC/DC output voltage DC/DC CONVERTER INPUT VOLTAGE (Vin) AND VB VOLTAGE SETTING The voltage at the CB pin is bootstrapped from the VS pin voltage by an amount equivalent to the VB pin voltage result of the bootstrap capacitance (C ...
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... expansion OUT1 OUT2 100 0.2 0.6 0.8 1 Synchronous rectifier length: 180 ns (typ) OUT1 tr (typ) OUT2 tf (typ) MB3871 VD3 – VD0 = 0100 (1.8 V) load fosc = 200 kHz setting 500 mV VS OUT1 OUT2 100 ns 0.4 0.6 0.8 1 ...
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... MB3871 APPLICATION EXAMPLE 20 signals setting voltage Output ...
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... REFERENCE DATA Conversion efficiency vs Load current characteristics 100 95 90 Vin Vin 0.1 (Output voltage = 1.8 V) Vin 22 V Vin 15 V 1.0 10.0 Load current (A) MB3871 (Continued) 21 ...
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... MB3871 (Continued CTL 100 Transient response for CTL ON/OFF (Output = 2.0 V, nonload 2ms Transient response for load abrupt change (Output = 2 100 200 400 ...
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... Working surfaces, tools and instruments should be properly grounded. • Workers should be grounded by a ground line with 250 resistance in series between the worker and ground. ORDERING INFORMATION Part number MB3871 PFV-G-BND Package 24-pin Plastic SSOP (FPT-24P-M03) MB3871 Remarks ...
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... MB3871 PACKAGE DIMENSION 24-pin Plastic SSOP (FPT-24P-M03) * 7.75±0.10(.305±.004) INDEX 0.65±0.12(.0256±.0047) 7.15(.281)REF 1994 FUJITSU LIMITED F24018S-2C These dimensions do not include resin protrusion. +0.20 1.25 –0.10 (Mounting height) +.008 .049 –.004 0.10(.004) * 5.60±0.10 7.60±0.20 6.60(.260) (.220±.004) (.299± ...
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... Tel: (65) 281-0770 Fax: (65) 281-0220 http://www.fmap.com.sg/ F9903 FUJITSU LIMITED Printed in Japan MB3871 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 ...