250mA 1.5A, Adjustable Current-Limit Switches programmable curren

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250mA 1.5A, Adjustable Current-Limit Switches programmable curren

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19-4814; 7/09
250mA 1.5A, Adjustable Current-Limit Switches
programmable current-limit switches feature internal current limiting prevent damage host devices faulty load conditions. These current-limit switches feature on-resistance operate from +1.7V +5.5V input voltage range. current limit adjustable from 250mA 1.5A, making these devices ideal SDIO (secure digital input/output) other load-switching applications. Each device family handles overcurrent event differently depending option selected. MAX14523A/MAX14523AL into autoretry mode, MAX14523B latches switch, MAX14523C features continuous current-limit mode. Additional safety features include thermal shutdown prevent overheating reverse-current blocking prevent current from being driven back into source. available tiny 8-pin, 3mm, TDFN package operate over -40°C +125°C automotive temperature range. Adjustable Current-Limit Threshold Low-Dropout Voltage (70mV Load Current) Short-Circuit Protection Thermal-Shutdown Protection Reverse-Current Protection 170µA (typ) Supply Current Shutdown Reverse Current, 0.6µA (max) +1.7V +5.5V Supply Voltage Range Tiny 8-Pin, 3mm, TDFN Package
Features
Accurate (±10%) Overload Current Limit
Typical Operating Circuit
BIAS VOLTAGE POWER SUPPLY CHARGE PUMP LOAD
Applications
SDIO Ports Ports Notebook Ports Cell Phones Players UTCA/ATCA Platforms
RSETI VPULLUP CURRENT REFERENCE
CONTROL LOGIC
FLAG ON(ON)* N.C.
MAX14523A MAX14523AL MAX14523B MAX14523C
Configuration appears data sheet.
MAX14523AL ONLY.
Ordering Information/Selector Guide
PART MAX14523AATA+ MAX14523ALATA+** MAX14523BATA+ MAX14523CATA+ PIN-PACKAGE TDFN-EP* TDFN-EP* TDFN-EP* TDFN-EP* MARK POLARTIY Active-High Active-Low Active-High Active-High OVERCURRENT RESPONSE Autoretry Autoretry Latch-Off Continuous
Note: devices specified over -40°C +125°C operating temperature range. +Denotes lead(Pb)-free package/RoHs-compliant package. Exposed pad. **Future product-contact factory availability.
Maxim Integrated Products
pricing, delivery, ordering information, please contact Maxim Direct 1-888-629-4642, visit Maxim's website www.maxim-ic.com.
250mA 1.5A, Adjustable Current-Limit Switches
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced GND.) FLAG, OUT, SETI .-0.3V Current into (Except OUT).20mA Short Circuit GND.Internally Limited Continuous Power Dissipation +70°C) multilayer board: 8-Pin TDFN (derate 24.4mW/°C above +70°C) .1952mW Junction-to-Case Thermal Resistance (JC) (Note .8.0°C/W Junction-to-Ambient Thermal Resistance (JA) (Note .41.0°C/W Operating Temperature Range .-40°C +125°C Junction Temperature .+150°C Storage Temperature Range .-65°C +150°C Lead Temperature (soldering, 10s) .+300°C
Note Package thermal resistances were obtained using method described JEDEC specification JESD51-7, using fourlayer board. detailed information package thermal considerations, refer
Stresses beyond those listed under "Absolute Maximum Ratings" cause permanent damage device. These stress ratings only, functional operation device these other conditions beyond those indicated operational sections specifications implied. Exposure absolute maximum rating conditions extended periods affect device reliability.
ELECTRICAL CHARACTERISTICS
(VIN +1.7V +5.5V, RSETI 94.2k, COUT 1µF, -40°C +125°C, unless otherwise noted. Typical values +3.3V, +25°C.) (Note
PARAMETER SUPPLY OPERATION Operating Voltage Quiescent Current Latchoff Current Shutdown Forward Current Shutdown Reverse Current INTERNAL Switch-On Resistance Forward-Current Limit (RSETI +2.48k ILIM Product Reverse Blocking Current Reverse Blocking Threshold FLAG Assertion Drop Voltage Threshold INPUT Input Leakage Input Logic-High Voltage Input Logic-Low Voltage ILEAK VON, VGND VOUT ILIM 3.3V, lower than ILIM RSETI 91.78k VOUT RSETI 563.12k VOUT ILIM 250mA 1500mA, VOUT VOUT 140mV, after reverse-currentlimit shutdown VOUT 300mV, falling until switch turns Increase (VIN VOUT) drop until FLAG asserts, limiting, 3.3V 1350 127.2 1500 141.4 1650 155.5 ILATCH SHDN IRSHDN switch 3.3V 3.3V, after overcurrent fault (MAX14523B) VIN, 5.5V, VOUT VIN, 1.7V, VOUT 5.5V (current into OUT) 0.01 SYMBOL CONDITIONS UNITS
250mA 1.5A, Adjustable Current-Limit Switches
ELECTRICAL CHARACTERISTICS (continued)
(VIN +1.7V +5.5V, RSETI 94.2k, COUT 1µF, -40°C +125°C, unless otherwise noted. Typical values +3.3V, +25°C.) (Note
PARAMETER FLAG OUTPUT FLAG Output Logic-Low Voltage FLAG Output Leakage Current DYNAMIC Turn-On Time Turn-Off Time Current-Limit Reaction Time Blanking Time Retry Time THERMAL PROTECTION Thermal Shutdown Thermal Shutdown Hysteresis Low-to-high +170 tLIM tBLANK tRETRY Time from ENABLE signal 3.3V, Figure Time from DISABLE signal VOUT 3.3V, Figure 3.3V, RSETI 91.78k 563.12k output high then short-circuit applied (Note MAX14523A/MAX14523AL (Note 14.5 ISINK VFLAG 5.5V, FLAG deasserted SYMBOL CONDITIONS UNITS
Note devices 100% tested 125°C. Electrical limits across full temperature range guaranteed design correlation. Note Blanking time retry time generated same oscillator. Therefore, ratio RETRY constant value tBLANK Figures
ON(ON)*
VOUT
tOFF
POLARITY SIGNAL REVERSED MAX14523AL ONLY.
Figure Timing Diagram Measuring Turn-On Time (tSS) Turn-Off Time (tOFF)
250mA 1.5A, Adjustable Current-Limit Switches
tBLANK tRETRY tBLANK tRETRY tBLANK tBLANK
CURRENT LIMIT LOAD CURRENT DEVICE GOES THERMAL-SHUTDOWN MODE
FLAG
Figure Autoretry Fault Diagram
tBLANK
tBLANK
CURRENT LIMIT LOAD CURRENT DEVICE GOES THERMAL-SHUTDOWN MODE
FLAG
Figure Latchoff Fault Diagram
250mA 1.5A, Adjustable Current-Limit Switches
Typical Operating Characteristics
(VIN +3.3V, 1µF, COUT 1µF, RSETI 94.2k, +25°C, unless otherwise noted.)
CURRENT LIMIT SUPPLY VOLTAGE
MAX14523A toc01
NORMALIZED CURRENT LIMIT TEMPERATURE
MAX14523A toc02
QUIESCENT SUPPLY CURRENT SUPPLY VOLTAGE
MAX14523A toc03
1.60
1.10
QUIESCENT SUPPLY CURRENT
1.55 CURRENT LIMIT
NORMALIZED CURRENT LIMIT
1.05
1.50
1.00
1.45
0.95
1.40 1.70 2.65 3.60 4.55 5.50 SUPPLY VOLTAGE
0.90 TEMPERATURE (°C)
1.70 2.65 3.60 4.55 5.50 SUPPLY VOLTAGE
QUIESCENT SUPPLY CURRENT TEMPERATURE
MAX14523A toc04
SHUTDOWN SUPPLY CURRENT TEMPERATURE
MAX14523A toc05
SHUTDOWN FORWARD CURRENT TEMPERATURE
SHUTDOWN FORWARD CURRENT +1.7V +5.5V VOUT
MAX14523A toc06
QUIESCENT SUPPLY CURRENT
QUIESCENT SUPPLY CURRENT
+3.3V TEMPERATURE (°C)
+3.3V
TEMPERATURE (°C)
TEMPERATURE (°C)
250mA 1.5A, Adjustable Current-Limit Switches
Typical Operating Characteristics (continued)
(VIN +3.3V, 1µF, COUT 1µF, RSETI 94.2k, +25°C, unless otherwise noted.)
SHUTDOWN REVERSE CURRENT TEMPERATURE
SHUTDOWN REVERSE CURRENT TEMPERATURE (°C) +1.7V, VOUT +5.5V
MAX14523A toc07
LATCHOFF CURRENT TEMPERATURE
MAX14523B LATCHOFF CURRENT +5.5V +3.3V
MAX14523A toc08
NORMALIZED ON-RESISTANCE SUPPLY VOLTAGE
1.15 NORMALIZED ON-RESISTANCE 1.10 1.05 1.00 0.95 0.90 0.85 0.80 1.70 2.65 3.60 VOLTAGE 4.55 5.50
MAX14523A toc09
1.20
TEMPERATURE (°C)
NORMALIZED ON-RESISTANCE SUPPLY TEMPERATURE
MAX14523A toc10
SWITCH TURN-ON TIME SUPPLY TEMPERATURE
MAX14523A toc11
SWITCH TURN-OFF TIME SUPPLY TEMPERATURE
SWITCH TURN-OFF TIME +3.3V +5.0V RLOAD
MAX14523A toc12
NORMALIZED ON-RESISTANCE
SWITCH TURN-ON TIME (ms)
RLOAD +5.0V
1000
+3.3V
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
250mA 1.5A, Adjustable Current-Limit Switches
Typical Operating Characteristics (continued)
(VIN +3.3V, 1µF, COUT 1µF, RSETI 94.2k, +25°C, unless otherwise noted.)
CURRENT LIMIT RESPONSE
MAX14523A toc13
CURRENT LIMIT RESPONSE
MAX14523A toc14
FLAG RESPONSE (OVERLOAD CONDITION)
MAX14523A toc15
SUDDEN SHORT APPLIED OUTPUT VOUT 2V/div
RLOAD 16.5 SUDDEN SHORT APPLIED OUTPUT VOUT 2V/div
RLOAD 16.5 SUDDEN SHORT APPLIED OUTPUT VFLAG 2V/div
IOUT 10A/div
IOUT 1A/div
IOUT 1A/div
2s/div
20ms/div
20ms/div
Description
MAX14523AL MAX14523A MAX14523B MAX14523C NAME FUNCTION
N.C. FLAG
Connection. internally connected. Connect N.C. leave unconnected. Open-Drain, Overload Indicator Output. FLAG goes when overload fault duration exceeds blanking time, reverse current detected, thermal shutdown mode active, SETI connected ground. Overload-Current Limit Adjust. Connect resistor from SETI program overcurrent limit. SETI connected switch turns FLAG asserted. SETI unconnected current limit 0mA. connect capacitance larger than 20pF SETI. Switch Output. Bypass with capacitor GND. Power Input. Bypass with ceramic capacitor GND. higher capacitance necessary prevent large load transients from pulling down supply voltage. Active-Low, Switch-ON Input. Drive turn switch. Active-High, Switch-ON Input. Drive high turn switch. Ground Exposed Pad. Internally connected GND. enhanced thermal dissipation, connect large copper ground plane. sole ground connection.
SETI
250mA 1.5A, Adjustable Current-Limit Switches
Functional Diagram
REVERSECURRENT PROTECTION THERMAL SHUTDOWN BUFFER
CONTROL LOGIC
FLAG
N.C.
TIMING CIRCUITRY
MAX14523A MAX14523AL MAX14523B MAX14523C
ON/(ON)*
BANDGAP REFERENCE
CURRENT LIMIT BUFFER SETI
MAX14523AL ONLY
Detailed Description
programmable current-limit switches operate from +1.7V +5.5V provide internal current limiting adjustable from 250mA 1.5A. These devices feature fixed blanking time, FLAG output that notifies processor when fault condition present.
Autoretry (MAX14523A/MAX14523AL)
When forward current reaches current threshold, tBLANK timer begins counting (Figure FLAG asserts overcurrent condition present tBLANK longer. timer resets overcurrent condition disappears before blanking time (tBLANK) elapsed. retry time delay (tRETRY) starts immediately after blanking time elapsed. During that time, switch latches off. tRETRY, switch turns again. fault still exists, cycle repeats. fault been removed, switch stays During this cycle, FLAG stays low. autoretry, temperature exceeds +170°C (typ) self heating, MAX14523A/MAX14523AL into thermal shutdown until temperature drops approximately 15°C (see Thermal Shutdown section.)
Programmable Current Limit/Threshold
resistor from SETI sets current limit/threshold switch (see Setting Current Limit/Threshold section). output current limited current threshold value time equal longer than tBLANK, output flag asserts MAX14523A/MAX14523AL enter autoretry mode, MAX14523B latches switch, MAX14523C enters continuous current-limit mode.
250mA 1.5A, Adjustable Current-Limit Switches
autoretry feature saves system power case overcurrent short-circuit condition. During tBLANK time, when switch supply current held current limit. During time tRETRY, when switch off, current through switch zero. Thus, average output current much less than programmed current limit. Calculate average output current using following equation: ILOAD ILIM [(tBLANK )/(tBLANK tRETRY)] With typical tBLANK 17.5ms typical tRETRY 560ms, duty cycle resulting power savings over switch being entire time.
Switch-On/Off Control
input MAX14523A/MAX14523B/ MAX14523C input MAX14523AL control switch, Table Toggle MAX14523B reset fault condition once short-circuit current detected device shuts down.
Reverse-Current Protection
feature reverse-current protection circuit that limits backflow current when reverse-current protection circuitry tripped. switch turns FLAG asserts without waiting tBLANK elapse. switch turns back FLAG deasserts when drops below reverse-current threshold 95mV (typ).
Latchoff (MAX14523B)
When forward current reaches current threshold, tBLANK timer begins counting (Figure FLAG asserts overcurrent condition present greater than tBLANK time. timer resets overcurrent condition disappears before BLANK elapsed. switch turns overcurrent condition continues beyond blanking time. Reset switch either toggling control logic cycling input voltage. temperature exceeds +170°C (typ) self heating, MAX14523B goes into thermal shutdown until temperature drops approximately 15°C (see Thermal Shutdown section).
FLAG Indicator
FLAG open-drain fault indicator output requires external pullup resistor supply. FLAG goes when following conditions occur: blanking time elapsed reverse-current protection tripped temperature exceeds +170°C SETI connected ground.
Thermal Shutdown
Thermal-shutdown circuitry protects devices from overheating. switch turns FLAG goes immediately when junction temperature exceeds +170°C (typ). switch turns again after device temperature drops approximately 15°C (typ).
Continuous Current Limit (MAX14523C)
When forward current reaches forward-current threshold, MAX14523C limits output current programmed current limit. FLAG asserts current limit present tBLANK deasserts when overload condition removed. this mode, temperature exceeds +170°C (typ) self heating, MAX14523C goes into thermal shutdown until temperature drops approximately 15°C (see Thermal Shutdown section).
Applications Information
Setting Current Limit/Threshold
resistor from SETI ground programs current limit/threshold value MAX14523A/MAX14523AL/ MAX14523B/MAX14523C. Table lists various current limit/thresholds different resistor values SETI. Leaving SETI unconnected selects current limit/threshold. Connecting SETI ground asserts FLAG. following formula calculate current limit: RSETI(k) 141400(V) 2.48(k) ILIM (mA)
Table Switch Truth Table
MAX14523A MAX14523B MAX14523C MAX14523AL SWITCH STATUS
250mA 1.5A, Adjustable Current-Limit Switches
Table Current Limit/Threshold Resistor Values
RSETI 91.78 563.12 (Open) TYPICAL CURRENT LIMIT/THRESHOLD (mA) 1500 1145
short possible reduce effect undesirable parasitic inductance. Place input output capacitors close possible device more than 5mm). must connected with wide short traces power bus. During normal operation, power dissipation small package temperature change minimal. output continuously shorted ground maximum supply voltage, operation switches with autoretry option does cause problems because total power dissipated during short scaled duty cycle: P(MAX) VIN(MAX) IOUT(MAX) tBLANK tRETRY tBLANK
RSETI value smaller than 91.78k. Note: Connecting capacitance larger than 20pF SETI cause instability.
Bypass Capacitor
Connect minimum capacitor from limit input voltage drop during momentary output short-circuit conditions. Larger capacitor values further reduce voltage undershoot input.
Attention must given MAX14523C continuous current-limit version when power dissipation during fault condition cause device reach thermal shutdown threshold.
Chip Information
PROCESS: BiCMOS
Bypass Capacitor
stable operation over full temperature range over full-programmable current-limit range, ceramic capacitor from ground. Excessive output capacitance cause false overcurrent condition decreased dv/dt across capacitor. Calculate maximum capacitive load (CMAX) value that connected using following formula: CMAX (µF) ILIM (mA) tBLANK(MIN) (ms)
Configuration
N.C. FLAG SETI
MAX14523A MAX14523AL MAX14523B MAX14523C
ON(ON)** N.C.
example, 3.3V, tBLANK 10ms, ILIM 300mA, CMAX equals 909µF.
TDFN
*CONNECT EXPOSED GND. MAX14523AL ONLY.
Layout Thermal Dissipation
optimize switch response time output shortcircuit conditions, very important keep traces
Package Information
latest package outline information land patterns, www.maxim-ic.com/packages. PACKAGE TYPE TDFN-EP PACKAGE CODE T833+2 DOCUMENT 21-0137
Maxim cannot assume responsibility circuitry other than circuitry entirely embodied Maxim product. circuit patent licenses implied. Maxim reserves right change circuitry specifications without notice time.
_Maxim Integrated Products, Gabriel Drive, Sunnyvale, 94086 408-737-7600 2009 Maxim Integrated Products Maxim registered trademark Maxim Integrated Products, Inc.

250mA 1.5A, Adjustable Current-Limit Switches programmable curren

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