ABCelectronique : portail d'information dans le domaine de l'électronique
 
 
Numéro de sérieMAX4971
CategoriePower Management => Protection and Isolation
DescriptionOvervoltage-Protection Controllers With A Low RON Internal FET
The MAX4970/MAX4971/MAX4972 family of overvoltage protection devices features a low 40m? (typ) RON internal FET and protect low-voltage systems against voltage faults up to +28V. These devices also drive an optional external pFET to protect against reverse-polarity input voltages. When the input voltage exceeds the overvoltage threshold, the internal FET is turned off to prevent damage to the protected components.
SociétéMaxim Integrated Products
DatasheetTélécharger MAX4971 datasheet
 
 
  • Description courte

  • The MAX4970/MAX4971/MAX4972 family of overvoltage protection devices features a low 40m (typ) RON internal FET and protect low-voltage systems against voltage faults to +28V. These devices also drive an optional external pFET to protect against reverse-polarity input voltages. When the input voltage exceeds the overvoltage threshold, the internal FET is turned off to prevent damage to the protected components. All switches feature a 2.3A (min) current-limit protection. During a short-circuit occurrence, the device operates in an autoretry mode where the internal MOSFET is turned on to check if the fault has been removed. The autoretry interval time is 15ms, and if the fault is removed, the MOSFET remains on. The MAX4970/MAX4971/MAX4972 feature an enable input (EN) that controls the operation of the internal nFET as well as the optional external pFET. The use of EN allows the external pFET to block reverse voltages independent of any signal present at the output. The overvoltage thresholds (OVLO) are preset 6.35V (MAX4971). The undervoltage thresholds (UVLO) are preset to 2.45V. When the input voltage drops below the UVLO, the devices enter a low-current standby mode. All devices are offered in a small 12-bump, WLP package and operate over the to +85°C extended temperature range.

    Features

    o Input Voltage Protection +28V o Integrated nFET Switch o Reverse Voltage Protection with External pFET o Enable Input o Preset Overvoltage Protection Trip Level (MAX4972) o Low-Current Undervoltage-Lockout Mode o Short-Circuit Protection (Autoretry) o Internal 15ms Startup Delay and Retry Times o Input-Voltage Power-Good Logic Output o Thermal-Shutdown Protection 1.5mm, 12-Bump WLP Package

    Applications
    Cell Phones Digital Still Cameras PDAs and Palmtop Devices MP3 Players

    PART MAX4971EWC+T MAX4972EWC+T PIN-PACKAGE 12 WLP 12 WLP 12 WLP TOP MARK AAB AAC PACKAGE CODE W121A2+1 UVLO (V) 2.45 OVLO (V) 6.35 4.65 ACOK ACTION UVLO only UVLO only UVLO and OVLO

    Note: All devices are specified over the to +85°C operating temperature range. +Denotes a lead-free/RoHS-compliant package. T = Tape-and-reel package.

    Typical Operating Circuit appears at end of data sheet.

    For pricing, delivery, and ordering information, please contact Maxim Direct 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.

    (Voltages referenced to GND.) OUT.............................................................-0.3V to +(IN + 0.3)V EN, to +30V Continuous Power Dissipation (TA = +70°C) for Multilayer Board: 12-Bump WLP (derate 8.5mW/°C above +70°C).....678mW WLP Package Junction-to-Ambient Thermal Resistance (JA) (Note 1)...........................................118°C/W Operating Temperature to +85°C Junction Temperature......................................................+150°C Storage Temperature to +150°C Lead Temperature (soldering).........................................+300°C

    Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.

    Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

    (VIN to +85°C, unless otherwise noted. Typical values are = +25°C.) (Note 2)

    PARAMETER Input Voltage Range SYMBOL VIN = 0V VIN 12V; GP clamp on Input Supply Current IIN = 0V VIN 5V (MAX4970), VIN 5.5V (MAX4971), VIN = 1.4V UVLO Supply Current IN Undervoltage Lockout IN Undervoltage Lockout Hysteresis MAX4970 VIN rising Overvoltage Trip Level VOVLO VIN falling IN Overvoltage Lockout Hysteresis MAX4971 MAX4972 IUVLO VUVLO VIN < VUVLO; VIN = 2.2V VIN falling VIN rising TA = TMIN to TMAX TA = TMIN to TMAX 50 60 CONDITIONS MIN 2.2 176 TYP MAX % µA UNITS V

    (VIN to +85°C, unless otherwise noted. Typical values are = +25°C.) (Note 2)

    PARAMETER Switch On-Resistance SYMBOL RON CONDITIONS VIN 5V (MAX4970), VIN 5.5V (MAX4971), VIN 3.8V (MAX4972); IOUT = 400mA VIN 5V (MAX4970), VIN 5.5V (MAX4971), VIN 3.8V (MAX4972) VIN - VGP, VIN EN = low, VGP = VIN 5V (MAX4970), VGP = VIN 5.5V (MAX4971), VGP = VIN EN = high, VIN 2.30 5.4 MIN TYP 40 MAX 90 UNITS m

    GP Pullup Resistor IN EN Input-Voltage High EN Input-Voltage Low EN Input Leakage Current ACOK Output-Low Voltage ACOK High Leakage Current Thermal Shutdown Thermal-Shutdown Hysteresis Maximum Output Capacitance

    COUT Time from VUVLO < VIN < VOVLO, RLOAD = 100, CLOAD 1µF to charge-pump enable VUVLO < VIN < VOVLO, RLOAD = 100, CLOAD = 1µF from EN low 90% of VOUT VUVLO < VIN to ACOK low (MAX4970/MAX4971) VUVLO < VIN < VOVLO to ACOK low (MAX4972) VIN < VUVLO to internal switch off VIN > VOVLO to internal switch off, RLOAD = 100 Overcurrent fault to internal switch off From overcurrent fault to internal switch turn-on, Figure 2

    TIMING CHARACTERISTICS (Figure 1) Debounce Time Switch Turn-On Time ACOK Assertion Time tINDBC tON tACOK µs ms

    Switch Turn-Off Time Current Limit Turn-Off Time Autoretry Time

    Note 2: All specifications are 100% production tested = +25°C, unless otherwise noted. Specifications are over to +85°C and are guaranteed by design.