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19-1059; Rev 0; 11/07
Overvoltage-Protection Controller with USB ESD Protection
General Description
The MAX4987AE/MAX4987BE are overvoltage protection devices with built-in ESD protection for USB data lines. These devices feature a low 100m (typ) RON internal nFET switch and protect low-voltage systems against voltage faults up to +28V. When the input voltage exceeds the overvoltage threshold or decreases below the undervoltage threshold, the internal nFET switch is turned off to prevent damage to the protected components. All switches feature a minimum 1.5A current-limit protection. During a short-circuit occurrence, the switch operates in an autoretry mode where the internal nFET switch is turned on to check if the fault has been removed. The autoretry interval is 30ms, and if the fault is removed, the nFET switch remains on. The MAX4987AE/MAX4987BE feature low-capacitance (3pF) ESD protection for USB data lines that allow transmission of high-speed USB 2.0 signals. The overvoltage threshold (OVLO) is preset to 6.15V. The undervoltage thresholds (UVLO) are preset to 2.55V (MAX4987AE) or 4.2V (MAX4987BE). When the input voltage drops below the undervoltage (UVLO) threshold, the devices enter a low-current standby mode. All devices are offered in a small 2mm x 3mm, 8-pin TDFN package and operate over the -40C to +85C extended temperature range. o o o o
Features
Input Voltage Protection Up to +28V Integrated Low RON (100m) nFET Switch Internal Overcurrent Protection 1.5A (min) Overcurrent Protection (Autoretry)
MAX4987AE/MAX4987BE
o Enable Input o Internal 30ms Startup Delay o Low-Capacitance USB High-Speed Data Line ESD Protection (3pF) 15kV Human Body Model 15kV IEC61000-4-2 Air Gap 6kV IEC61000-4-2 Contact o Thermal-Shutdown Protection o 2mm x 3mm, 8-Pin TDFN Package
Pin Configuration
TOP VIEW
OUT ACOK 8 7 EN 6 VCC 5
Applications
Cell Phones Media Players
MAX4987AE/ MAX4987BE
*EP 1 IN 2 CD+ 3 GND 4 CD-
Typical Operating Circuit appears at end of data sheet.
*CONNECT EXPOSED PAD TO GND.
TDFN-EP 2mm x 3mm
Ordering Information/Selector Guide
PART MAX4987AEETA+ MAX4987BEETA+* PINPACKAGE 8 TDFN-EP** 8 TDFN-EP** TOP MARK AAI AAJ PACKAGE CODE T823-1 T823-1 UVLO (V) 2.55 4.2 OVLO (V) 6.15 6.15 OVERCURRENT MODE Autoretry Autoretry
Note: All devices are specified over the -40C to +85C operating temperature range. +Denotes a lead-free package. *Future product--contact factory for availability. **EP = Exposed paddle.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Overvoltage-Protection Controller with USB ESD Protection MAX4987AE/MAX4987BE
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND.) IN ............................................................................-0.3V to +30V OUT.............................................................-0.3V to +(IN + 0.3V) VCC, EN, ACOK, CD+, CD- ......................................-0.3V to +6V Continuous Power Dissipation (TA = +70C) for multilayer board: 8-Pin TDFN (derate 16.7mW/C above +70C) .........1333mW Package Junction-to-Ambient Thermal Resistance (JA) (Note 1) ................................................................60.0C/W Package Junction-to-Case Thermal Resistance (JC) (Note 1) ................................................................10.8C/W Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering) .........................................+300C
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a 4-layer board. For detailed information on package thermal considerations, go 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.
ELECTRICAL CHARACTERISTICS
(VIN = +2.2V to +28V, TA = -40C to +85C, unless otherwise noted. Typical values are at VIN = +5V and TA = +25C.)
PARAMETER ANALOG SWITCH Input-Voltage Range VCC Input Voltage Input Supply Current UVLO Supply Current VIN VCC IIN IUVLO EN = 0V, VIN > VUVLO EN = 5V, VIN > VUVLO VIN < VUVLO (VIN falling) IN Undervoltage Lockout VUVLO (VIN rising) IN Undervoltage Lockout Hysteresis Overvoltage Trip Level IN Overvoltage Lockout Hysteresis Switch On-Resistance Overcurrent Protection Threshold Maximum Output Capacitance CD+ and CD- Leakage Current CD+ and CD- Capacitance DIGITAL SIGNALS ACOK Output Low Voltage ACOK High-Leakage Current EN Input-Voltage High EN Input-Voltage Low EN Input-Leakage Current VIH VIL ILEAK VEN = 5.5V -1 VOL ISINK = 1mA VACOK = 5.5V, flag deasserted 1.4 0.4 +1 0.4 1 V A V V A ILKG_CD CCD RON ILIM VIN = 5V, no overcurrent shutdown VCC = 5.5V, VCD_ = 0V, 3.3V f = 1MHz, VCD_ = 0.5P-P -300 3 VIN = 5V, IOUT = 500mA 1.5 1000 +300 VOVLO (VIN rising) (VIN falling) 5.55 5.5 1 100 200 4.2 MAX4987AE MAX4987BE MAX4987AE MAX4987BE 2.3 3.8 2.35 3.85 2.55 4.2 1 6.15 6.45 2.75 4.45 % V % m A F nA pF V 60 50 2.2 28 5.5 150 100 40 V V A A SYMBOL CONDITIONS MIN TYP MAX UNIT
2
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Overvoltage-Protection Controller with USB ESD Protection
ELECTRICAL CHARACTERISTICS (continued)
(VIN = +2.2V to +28V, TA = -40C to +85C, unless otherwise noted. Typical values are at VIN = +5V and TA = +25C.)
PARAMETER TIMING CHARACTERISTICS (Note 2) Debounce Time ACOK Assertion Time Switch Turn-On Time Switch Turn-Off Time Current-Limit Turn-Off Time Autoretry Time THERMAL PROTECTION Thermal Shutdown Thermal-Shutdown Hysteresis ESD PROTECTION Human Body Model CD+ and CDAll Other Pins IEC61000-4-2 Air Gap IEC61000-4-2 Contact Human Body Model 15 15 6 2 kV kV TSHDN 150 40 C C tINDBC tACOK tON tOFF tBLANK tRETRY Time from VUVLO < VIN < VOVLO to charge-pump enable VUVLO < VIN < VOVLO, to ACOK low VUVLO < VIN < VOVLO, RLOAD = 100, from 10% to 90% of VOUT VIN < VUVLO or VIN > VOVLO to internal switch off, RLOAD = 100 Overcurrent fault to internal switch off From overcurrent fault to internal switch turn-on 10 30 30 30 3 10 ms ms ms s s ms SYMBOL CONDITIONS MIN TYP MAX UNIT
MAX4987AE/MAX4987BE
Note 2: All timing is specified using 20% and 80% levels, unless otherwise noted.
Typical Operating Characteristics
(TA = +25C, unless otherwise noted.)
IN SUPPLY CURRENT vs. IN VOLTAGE
MAX4987AE
MAX4987AE/BE toc01
SWITCH ON-RESISTANCE vs. TEMPERATURE
MAX4987AE/BE toc02
NORMALIZED UVLO THRESHOLD vs. TEMPERATURE
1.008 NORMALIZED UVLO THRESHOLD (V) 1.006 1.004 1.002 1.000 0.998 0.996 0.994 0.992 0.990
MAX4987AE/BE toc03
80 70 IN SUPPLY CURRENT (A) 60 50 40 30 20 10 0 2
200 180 160 140 RON (m) 120 100 80 60 40 20 0
1.010
6
10
18 IN VOLTAGE (V)
14
22
26
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (C)
TEMPERATURE (C)
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Overvoltage-Protection Controller with USB ESD Protection MAX4987AE/MAX4987BE
Typical Operating Characteristics
(TA = +25C, unless otherwise noted.)
NORMALIZED OVLO THRESHOLD vs. TEMPERATURE
MAX4987AE/BE toc04
NORMALIZED CURRENT LIMIT vs. TEMPERATURE
1.16 1.12 CURRENT LIMIT (%) 1.08 1.04 1.00 0.96 0.92 0.88 0.84 0.80 0 -40 -15 10 35 60 85 -40 -15
MAX4987AE/BE toc05
TURN-ON TIME vs. TEMPERATURE
MAX4987AE/BE toc06
1.010 1.008 NORMALIZED OVLO THRESHOLD (V) 1.006 1.004 1.002 1.000 0.998 0.996 0.994 0.992 0.990 -40 -15 10 35 60
1.20
5.0
4.0 TURN ON TIME (ms)
3.0
2.0
1.0
85
10
35
60
85
TEMPERATURE (C)
TEMPERATURE (C)
TEMPERATURE (C)
DEBOUNCE TIME vs. TEMPERATURE
MAX4987AE/BE toc07
POWER-UP RESPONSE
MAX4987AE/BE toc08
OVERVOLTAGE FAULT RESPONSE
MAX4987AE/BE toc09
50.0 45.0 DEBOUNCE TIME (ms) 40.0 35.0 30.0 25.0 20.0 -40 -15 10 35 60
VIN 5V/div VOUT 5V/div VACOK 5V/div IOUT 1A/div
8V 5V 8V 5V 0
VIN 5V/div VOUT 5V/div VACOK 5V/div IOUT 1A/div
0
0 2s/div
85
10ms/div
TEMPERATURE (C)
UNDERVOLTAGE FAULT RESPONSE
MAX4987AE/BE toc10
SHORT-CIRCUIT FAULT RESPONSE
MAX4987AE/BE toc11
5 2 VIN 2V/div VOUT 2V/div 0 VACOK 5V/div IOUT 1A/div 4s/div 0 0
CIN = 100F VIN 5V/div VOUT 5V/div VACOK 5V/div IOUT 1A/div
0
0
0 10s/div
0
4
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Overvoltage-Protection Controller with USB ESD Protection
Pin Description
PIN 1 2 3 4 5 6 7 8 EP NAME IN CD+ GND CDVCC EN ACOK OUT EP FUNCTION Voltage Input. Bypass IN with a 1F ceramic capacitor as close to the device as possible to obtain 15kV HBM ESD protection. No capacitor required to obtain 2kV HBM ESD protection. USB Data Line Ground USB Data Line Positive Supply-Voltage Input. VCC is required only when USB signals are present. Enable Active-Low Input. Drive EN low to enable the switch. Drive EN high to disable the switch. Open-Drain Adapter-Voltage Indicator Output. ACOK is driven low after the VIN voltage is stable between UVLO and OVLO for 30ms (typ). Connect a pullup resistor from ACOK to the logic I/O voltage of the host system. Output Voltage. Output of internal switch. Exposed Pad. Connect exposed pad to ground. Do not use EP as a sole ground connection.
MAX4987AE/MAX4987BE
Functional Diagram
IN OVERCURRENT FAULT CHARGE PUMP
OUT
ACOK
+ VBG REFERENCE + -
OV EN
CONTROL LOGIC
EN UV
VCC
CD+
CD-
MAX4987AE/ MAX4987BE
GND
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5
Overvoltage-Protection Controller with USB ESD Protection MAX4987AE/MAX4987BE
OVLO
UVLO
IN tON 90% VOUT
tOFF tOFF
OUT tINDBC
10% VOUT tINDBC tINDBC
ACOK
Figure 1. MAX4987AE/MAX4987BE Timing Diagram
Detailed Description
The MAX4987AE/MAX4987BE are overvoltage protection devices with integrated ESD protection for USB data lines. These devices feature a low RON internal FET and protect low-voltage systems against voltage faults up to +28V. If the input voltage exceeds the overvoltage threshold, the internal nFET switch is turned off to prevent damage to the protected components. The 30ms debounce time prevents false turn-on of the internal nFET switch during startup. An open-drain activelow logic output is available to signal that a successful power-up has occurred.
Internal nFET Switch
The MAX4987AE/MAX4987BE incorporate an internal nFET switch with a 100m (typ) on-resistance. The nFET switch is internally driven by a charge pump that generates a voltage above the input voltage. The MAX4987AE/MAX4987BE is equipped with a 1.5A (min) current-limit protection that turns off the nFET switch within 5s (typ) during an overcurrent fault condition.
Autoretry
The MAX4987AE/MAX4987BE have an overcurrent autoretry function that turns on the nFET switch again after a 30ms (typ) retry time (see Figure 2). If the faulty load condition is still present after the blanking time, the switch turns off again and the cycle is repeated. The fast turn-off time and 30ms retry time result in a very low duty cycle in order to keep power consumption low. If the faulty load condition is not present, the switch remains on.
Device Operation
The MAX4987AE/MAX4987BE have an internal oscillator and charge pump that control the turn-on of the internal nFET switch. The internal oscillator controls the timers that enable the turn-on of the charge pump and controls the state of the open-drain ACOK output. If VIN < V UVLO or if V IN > V OVLO , the internal oscillator remains off, thus disabling the charge pump. If VUVLO < VIN < VOVLO, the internal charge pump is enabled. The charge-pump startup, after a 30ms internal delay, turns on the internal nFET switch and asserts ACOK (see Figure 1). At any time, if VIN drops below VUVLO or rises above VOVLO, ACOK is pulled high and the charge pump is disabled.
6
Undervoltage Lockout (UVLO)
The MAX4987AE has a 2.55V undervoltage-lockout threshold (UVLO), while the MAX4987BE has a 4.15V UVLO threshold. When VIN is less than VUVLO, ACOK is high impedance.
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Overvoltage-Protection Controller with USB ESD Protection
Overvoltage Lockout (OVLO)
The MAX4987AE/MAX4987BE have a 6.15V (typ) overvoltage threshold (OVLO). When VIN is greater than VOVLO, ACOK is high impedance.
tOFF nFET SWITCH ON nFET SWITCH ON
MAX4987AE/MAX4987BE
ACOK
ACOK is an active-low open-drain output that asserts low when VUVLO < VIN < VOVLO following the 30ms (typ) debounce period. Connect a pullup resistor from ACOK to the logic I/O voltage of the host system. During a short-circuit fault, ACOK may deassert due to VIN not being in the valid operating voltage range.
tRETRY
SWITCH OFF
Thermal-Shutdown Protection
The MAX4987AE/MAX4987BE feature thermal-shutdown circuitry. The internal nFET switch turns off when the junction temperature exceeds TSHDN and immediately goes into a fault mode. The device exits thermal shutdown after the junction temperature cools by +40C (typ).
CURRENT THROUGH nFET SWITCH
ILIM
Figure 2. Autoretry Timing Diagram
Applications Information
IN Bypass Capacitor
For most applications, bypass IN to GND with a 1F ceramic capacitor as close to the device as possible to enable 15kV HBM ESD protection on IN. If 15kV HBM ESD protection is not required, there is no capacitor required at IN. If the power source has significant inductance due to long lead length, take care to prevent overshoots due to the LC tank circuit and provide protection if necessary to prevent exceeding the absolute maximum rating on IN.
RC 1M CHARGE CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE RD 1.5k DISCHARGE RESISTANCE DEVICE UNDER TEST
Cs 100pF
STORAGE CAPACITOR
ESD Test Conditions
ESD performance depends on a number of conditions. The MAX4987AE/MAX4987BE are specified for 15kV HBM ESD protection on the CD+, CD-, and IN pins when IN is bypassed to ground with a 1F ceramic capacitor. The CD+ and CD- inputs are also protected against 15kV airgap and 6kV contact IEC61000-4-2 ESD events.
Figure 3. Human Body ESD Test Model
IP 100% 90% AMPERES 36.8% 10% 0 0 tRL
Ir
PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE)
Human Body Model
Figure 3 shows the Human Body Model, and Figure 4 shows the current waveform it generates when discharged into a low impedance. This model consists of a 100pF capacitor charged to the ESD voltage of interest, that is then discharged into the device through a 1.5k resistor.
IEC 61000-4-2
The IEC 61000-4-2 standard covers ESD testing and performance of finished equipment. It does not specifically refer to integrated circuits. The MAX4987AE/ MAX4987BE
TIME tDL CURRENT WAVEFORM
Figure 4. Human Body Current Waveform
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7
Overvoltage-Protection Controller with USB ESD Protection MAX4987AE/MAX4987BE
are specified for 15kV Air-Gap Discharge and 6kV Contact Discharge IEC 61000-4-2 on the CD+ and CDpins. The major difference between tests done using the Human Body Model and IEC 61000-4-2 is a higher peak current in IEC 61000-4-2, due to lower series resistance. Hence, the ESD withstand voltage measured to IEC 61000-4-2 generally is lower than that measured using the Human Body Model. Figure 5 shows the IEC 610004-2 model. The Contact Discharge method connects the probe to the device before the probe is charged. The Air-Gap Discharge test involves approaching the device with a charged probe.
RC 50M TO 100M CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE RD 330 DISCHARGE RESISTANCE DEVICE UNDER TEST
Cs 150pF
STORAGE CAPACITOR
Figure 5. IEC 61000-4-2 ESD Test Model
Typical Operating Circuit
IN OVERCURRENT FAULT CHARGE PUMP
OUT VIO
BATTERY CHARGER
PHONE LOAD
ACOK
+ VBG REFERENCE + -
OV
CONTROL LOGIC VCC
EN UV VCC
VCC D+ DUSB TRANSCEIVER
VBUS USB CONNECTOR D+ DCD+
CD-
MAX4987AE/ MAX4987BE
GND
Chip Information
PROCESS: BiCMOS
8 _______________________________________________________________________________________
Overvoltage-Protection Controller with USB ESD Protection
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) 8L, TDFN.EPS
PACKAGE OUTLINE 8L TDFN, EXPOSED PAD, 2x3x0.8mm
MAX4987AE/MAX4987BE
21-0174
B
1 2
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9
Overvoltage-Protection Controller with USB ESD Protection MAX4987AE/MAX4987BE
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)
DIMENSIONS SYMBOL A E D A1 L k A2 N e b 0.18 MIN. 0.70 2.95 1.95 0.00 0.30 NOM. 0.75 3.00 2.00 0.02 0.40 0.20 MIN. 0.20 REF. 8 0.50 BSC 0.25 MAX. 0.80 3.05 2.05 0.05 0.50 PKG. CODE T823-1 MIN. 1.60 EXPOSED PAD PACKAGE E2 NOM. 1.75 MAX. 1.90 MIN. 1.50 D2 NOM. 1.63 MAX. 1.75
0.30
PACKAGE OUTLINE 8L TDFN, EXPOSED PAD, 2x3x0.8mm
21-0174
B
2 2
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2007 Maxim Integrated Products
SPRINGER
is a registered trademark of Maxim Integrated Products, Inc.

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