19-1059; Rev 0; 11/07
Overvoltage-Protection Controller
with USB ESD Protection
The MAX4987AE/MAX4987BE are overvoltage protection
devices with built-in ESD protection for USB data lines.
These devices feature a low 100mΩ (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 -40°C to +85°C
extended temperature range.
Features
o
o
o
o
Input Voltage Protection Up to +28V
Integrated Low RON (100mΩ) nFET Switch
Internal Overcurrent Protection 1.5A (min)
Overcurrent Protection (Autoretry)
o Enable Input
o Internal 30ms Startup Delay
o Low-Capacitance USB High-Speed Data Line ESD
Protection (3pF)
±15kV Human Body Model
±15kV IEC 61000-4-2 Air Gap
±6kV IEC 61000-4-2 Contact
o Thermal-Shutdown Protection
o 2mm x 3mm, 8-Pin TDFN Package
Pin Configuration
TOP VIEW
OUT ACOK
8
Applications
7
EN
VCC
6
5
MAX4987AE/
MAX4987BE
Cell Phones
Media Players
*EP
Typical Operating Circuit appears at end of data sheet.
*CONNECT EXPOSED
PAD TO GND.
1
2
3
4
IN
CD+
GND
CD-
TDFN-EP
2mm x 3mm
Ordering Information/Selector Guide
PINPACKAGE
PART
TOP MARK
PACKAGE
CODE
UVLO (V)
OVLO (V)
OVERCURRENT
MODE
MAX4987AEETA+
8 TDFN-EP**
AAI
T823-1
2.55
6.15
Autoretry
MAX4987BEETA+*
8 TDFN-EP**
AAJ
T823-1
4.2
6.15
Autoretry
Note: All devices are specified over the -40°C to +85°C operating temperature range.
+Denotes a lead-free package.
*Future product—contact factory for availability.
**EP = Exposed paddle.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX4987AE/MAX4987BE
General Description
MAX4987AE/MAX4987BE
Overvoltage-Protection Controller
with USB ESD Protection
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 = +70°C) for multilayer board:
8-Pin TDFN (derate 16.7mW/°C above +70°C) .........1333mW
Package Junction-to-Ambient Thermal Resistance
(θJA) (Note 1) ................................................................60.0°C/W
Package Junction-to-Case Thermal Resistance
(θJC) (Note 1) ................................................................10.8°C/W
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C 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 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 = -40°C to +85°C, unless otherwise noted. Typical values are at VIN = +5V and TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNIT
ANALOG SWITCH
Input-Voltage Range
VIN
VCC Input Voltage
VCC
Input Supply Current
IIN
UVLO Supply Current
IUVLO
2.2
60
150
EN = 5V, VIN > VUVLO
50
100
VIN < VUVLO
40
MAX4987AE
MAX4987BE
3.8
2.35
2.55
2.75
MAX4987BE
3.85
4.2
4.45
(VIN rising)
5.55
6.15
(VIN falling)
5.5
IN Undervoltage Lockout Hysteresis
1
VOVLO
IN Overvoltage Lockout Hysteresis
RON
Overcurrent Protection Threshold
ILIM
Maximum Output Capacitance
CD+ and CD- Leakage Current
CD+ and CD- Capacitance
VIN = 5V, IOUT = 500mA
100
1.5
VIN = 5V, no overcurrent shutdown
ILKG_CD
VCC = 5.5V, VCD_ = 0V, 3.3V
CCD
f = 1MHz, VCD_ = 0.5P-P
VOL
ISINK = 1mA
µA
V
%
200
4.2
1000
-300
V
%
6.45
1
Switch On-Resistance
µA
2.3
MAX4987AE
VUVLO
(VIN rising)
Overvoltage Trip Level
V
V
EN = 0V, VIN > VUVLO
(VIN falling)
IN Undervoltage Lockout
28
5.5
mΩ
A
µF
+300
3
nA
pF
DIGITAL SIGNALS
ACOK Output Low Voltage
ACOK High-Leakage Current
VIH
EN Input-Voltage Low
VIL
EN Input-Leakage Current
2
VACOK = 5.5V, flag deasserted
EN Input-Voltage High
ILEAK
0.4
V
1
µA
0.4
V
+1
µA
1.4
VEN = 5.5V
-1
_______________________________________________________________________________________
V
Overvoltage-Protection Controller
with USB ESD Protection
(VIN = +2.2V to +28V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VIN = +5V and TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNIT
TIMING CHARACTERISTICS (Note 2)
Debounce Time
tINDBC
Time from VUVLO < VIN < VOVLO to
charge-pump enable
30
ms
ACOK Assertion Time
tACOK
VUVLO < VIN < VOVLO, to ACOK low
30
ms
3
ms
Switch Turn-On Time
tON
VUVLO < VIN < VOVLO, RLOAD = 100Ω,
from 10% to 90% of VOUT
Switch Turn-Off Time
tOFF
VIN < VUVLO or VIN > VOVLO to internal
switch off, RLOAD = 100Ω
Current-Limit Turn-Off Time
Autoretry Time
10
µs
tBLANK
Overcurrent fault to internal switch off
10
µs
tRETRY
From overcurrent fault to internal switch
turn-on
30
ms
THERMAL PROTECTION
Thermal Shutdown
TSHDN
Thermal-Shutdown Hysteresis
150
°C
40
°C
ESD PROTECTION
Human Body Model
±15
CD+ and CD-
IEC 61000-4-2 Air Gap
±15
IEC 61000-4-2 Contact
±6
All Other Pins
Human Body Model
±2
kV
kV
Note 2: All timing is specified using 20% and 80% levels, unless otherwise noted.
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
SWITCH ON-RESISTANCE
vs. TEMPERATURE
160
140
RON (mΩ)
50
180
40
30
120
100
80
60
20
40
10
20
0
0
2
6
10
14
18
IN VOLTAGE (V)
22
26
1.010
MAX4987AE/BE toc03
60
MAX4987AE/BE toc02
MAX4987AE
70
IN SUPPLY CURRENT (μA)
200
MAX4987AE/BE toc01
80
NORMALIZED UVLO THRESHOLD
vs. TEMPERATURE
1.008
NORMALIZED UVLO THRESHOLD (V)
IN SUPPLY CURRENT
vs. IN VOLTAGE
1.006
1.004
1.002
1.000
0.998
0.996
0.994
0.992
0.990
-40
-15
10
35
TEMPERATURE (°C)
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
_______________________________________________________________________________________
3
MAX4987AE/MAX4987BE
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
NORMALIZED OVLO THRESHOLD
vs. TEMPERATURE
1.12
1.002
1.000
0.998
0.996
1.08
1.04
1.00
0.96
0.92
0.994
0.88
0.992
0.84
0.990
4.0
-15
10
35
60
85
3.0
2.0
1.0
0
0.80
-40
MAX4987AE/BE toc06
1.004
1.16
TURN ON TIME (ms)
1.006
5.0
MAX4987AE/BE toc05
1.20
CURRENT LIMIT (%)
NORMALIZED OVLO THRESHOLD (V)
1.008
TURN-ON TIME
vs. TEMPERATURE
NORMALIZED CURRENT LIMIT
vs. TEMPERATURE
MAX4987AE/BE toc04
1.010
-40
-15
10
35
60
TEMPERATURE (°C)
TEMPERATURE (°C)
DEBOUNCE TIME
vs. TEMPERATURE
POWER-UP RESPONSE
-40
85
-15
10
35
MAX4987AE/BE toc07
45.0
35.0
MAX4987AE/BE toc09
VACOK
5V/div
30.0
IOUT
1A/div
25.0
8V
5V
8V
5V
VIN
5V/div
VOUT
5V/div
0
VACOK
5V/div
0
IOUT
1A/div
0
20.0
-15
10
35
60
10ms/div
85
2μs/div
TEMPERATURE (°C)
UNDERVOLTAGE FAULT RESPONSE
SHORT-CIRCUIT FAULT RESPONSE
MAX4987AE/BE toc10
MAX4987AE/BE toc11
5
VIN
2V/div
2
VOUT
2V/div
0
CIN = 100μF
VIN
5V/div
VOUT
5V/div
0
0
VACOK
5V/div
0
IOUT
1A/div
0
4μs/div
4
85
OVERVOLTAGE FAULT RESPONSE
VIN
5V/div
VOUT
5V/div
40.0
-40
60
TEMPERATURE (°C)
MAX4987AE/BE toc08
50.0
DEBOUNCE TIME (ms)
MAX4987AE/MAX4987BE
Overvoltage-Protection Controller
with USB ESD Protection
VACOK
5V/div
0
IOUT
1A/div
0
10μs/div
_______________________________________________________________________________________
Overvoltage-Protection Controller
with USB ESD Protection
PIN
NAME
1
IN
2
CD+
USB Data Line
3
GND
Ground
4
CD-
USB Data Line
5
VCC
Positive Supply-Voltage Input. VCC is required only when USB signals are present.
6
EN
7
ACOK
8
OUT
EP
EP
FUNCTION
Voltage Input. Bypass IN with a 1µF ceramic capacitor as close to the device as possible to obtain
±15kV HBM ESD protection. No capacitor required to obtain ±2kV HBM ESD protection.
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.
Functional Diagram
IN
OUT
OVERCURRENT
FAULT
CHARGE
PUMP
ACOK
+
VBG
REFERENCE
CONTROL
LOGIC
OV
-
EN
+
-
EN
UV
VCC
CD+
MAX4987AE/
MAX4987BE
CD-
GND
_______________________________________________________________________________________
5
MAX4987AE/MAX4987BE
Pin Description
MAX4987AE/MAX4987BE
Overvoltage-Protection Controller
with USB ESD Protection
OVLO
UVLO
tOFF
IN
tOFF
tON
90% VOUT
10% VOUT
OUT
tINDBC
tINDBC
tINDBC
ACOK
Figure 1. MAX4987AE/MAX4987BE Timing Diagram
Detailed Description
Internal nFET Switch
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.
The MAX4987AE/MAX4987BE incorporate an internal
nFET switch with a 100mΩ (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 5µs (typ) during an overcurrent fault condition.
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
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.
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.
_______________________________________________________________________________________
Overvoltage-Protection Controller
with USB ESD Protection
MAX4987AE/MAX4987BE
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
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.
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 +40°C (typ).
tRETRY
CURRENT
THROUGH
nFET SWITCH
SWITCH OFF
ILIM
Figure 2. Autoretry Timing Diagram
Applications Information
IN Bypass Capacitor
For most applications, bypass IN to GND with a 1µF
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
1MΩ
CHARGE CURRENTLIMIT RESISTOR
HIGHVOLTAGE
DC
SOURCE
Cs
100pF
RD
1.5kΩ
DISCHARGE
RESISTANCE
DEVICE
UNDER
TEST
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 1µF ceramic
capacitor. The CD+ and CD- inputs are also protected
against ±15kV Air Gap and ±6kV contact IEC 61000-42 ESD events.
Figure 3. Human Body ESD Test Model
IP 100%
90%
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
1.5kΩ 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
AMPERES
36.8%
10%
0
0
tRL
TIME
tDL
CURRENT WAVEFORM
Figure 4. Human Body Current Waveform
_______________________________________________________________________________________
7
MAX4987AE/MAX4987BE
Overvoltage-Protection Controller
with USB ESD Protection
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.
RD
330Ω
RC
50MΩ TO 100MΩ
DISCHARGE
RESISTANCE
CHARGE-CURRENTLIMIT RESISTOR
HIGHVOLTAGE
DC
SOURCE
Cs
150pF
DEVICE
UNDER
TEST
STORAGE
CAPACITOR
Figure 5. IEC 61000-4-2 ESD Test Model
Typical Operating Circuit
IN
OUT
BATTERY
CHARGER
PHONE
LOAD
VIO
OVERCURRENT
FAULT
CHARGE
PUMP
ACOK
+
VBG
REFERENCE
CONTROL
LOGIC
OV
-
EN
+
-
UV
VCC
USB
CONNECTOR
VCC
VCC
VBUS
D+
D+
D-
D-
CD+
CD-
USB
TRANSCEIVER
MAX4987AE/
MAX4987BE
GND
Chip Information
PROCESS: BiCMOS
8
_______________________________________________________________________________________
Overvoltage-Protection Controller
with USB ESD Protection
8L, TDFN.EPS
PACKAGE OUTLINE
8L TDFN, EXPOSED PAD, 2x3x0.8mm
21-0174
B
1
2
_______________________________________________________________________________________
9
MAX4987AE/MAX4987BE
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.)
MAX4987AE/MAX4987BE
Overvoltage-Protection Controller
with USB ESD Protection
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
MIN.
0.70
NOM.
0.75
MAX.
0.80
2.95
3.00
3.05
1.95
0.00
2.00
0.02
2.05
0.05
0.30
0.40
0.20 MIN.
0.20 REF.
0.50
N
e
b
0.18
8
0.50 BSC
0.25
EXPOSED PAD PACKAGE
E2
D2
PKG.
CODE
MIN.
NOM.
MAX.
MIN.
NOM.
MAX.
T823-1
1.60
1.75
1.90
1.50
1.63
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
© 2007 Maxim Integrated Products
SPRINGER
is a registered trademark of Maxim Integrated Products, Inc.
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