General Description
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 volt-
age faults up to +28V. When the input voltage exceeds
the overvoltage threshold or decreases below the under-
voltage threshold, the internal nFET switch is turned off to
prevent damage to the protected components.
All switches feature a minimum 1.5A current-limit pro-
tection. 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) thresh-
old, 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.
Applications
Cell Phones
Media Players
Features
oInput Voltage Protection Up to +28V
oIntegrated Low RON (100mΩ) nFET Switch
oInternal Overcurrent Protection 1.5A (min)
oOvercurrent Protection (Autoretry)
oEnable Input
oInternal 30ms Startup Delay
oLow-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
oThermal-Shutdown Protection
o2mm x 3mm, 8-Pin TDFN Package
MAX4987AE/MAX4987BE
Overvoltage-Protection Controller
with USB ESD Protection
________________________________________________________________
Maxim Integrated Products
1
Ordering Information/Selector Guide
19-1059; Rev 0; 11/07
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.
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.
Typical Operating Circuit appears at end of data sheet.
PART PIN-
PACKAGE 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
Pin Configuration
134
865
OUT VCC
MAX4987AE/
MAX4987BE
2
7
IN
*CONNECT EXPOSED
PAD TO GND.
GND CD-CD+
TDFN-EP
2mm x 3mm
TOP VIEW ENACOK
*EP
MAX4987AE/MAX4987BE
Overvoltage-Protection Controller
with USB ESD Protection
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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.)
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.
(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
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNIT
ANALOG SWITCH
Input-Voltage Range VIN 2.2 28 V
VCC Input Voltage VCC 5.5 V
EN = 0V, VIN > VUVLO 60 150
Input Supply Current IIN EN = 5V, VIN > VUVLO 50 100 µA
UVLO Supply Current IUVLO VIN < VUVLO 40 µA
MAX4987AE 2.3
(VIN falling) MAX4987BE 3.8
MAX4987AE 2.35 2.55 2.75
IN Undervoltage Lockout VUVLO
(VIN rising) MAX4987BE 3.85 4.2 4.45
V
IN Undervoltage Lockout Hysteresis 1%
(VIN rising) 5.55 6.15 6.45
Overvoltage Trip Level VOVLO (VIN falling) 5.5 V
IN Overvoltage Lockout Hysteresis 1%
Switch On-Resistance RON VIN = 5V, IOUT = 500mA 100 200 mΩ
Overcurrent Protection Threshold ILIM 1.5 4.2 A
Maximum Output Capacitance VIN = 5V, no overcurrent shutdown 1000 µF
CD+ and CD- Leakage Current ILKG_CD VCC = 5.5V, VCD_ = 0V, 3.3V -300 +300 nA
CD+ and CD- Capacitance CCD f = 1MHz, VCD_ = 0.5P-P 3pF
DIGITAL SIGNALS
ACOK Output Low Voltage VOL ISINK = 1mA 0.4 V
ACOK High-Leakage Current VACOK = 5.5V, flag deasserted 1 µA
EN Input-Voltage High VIH 1.4 V
EN Input-Voltage Low VIL 0.4 V
EN Input-Leakage Current ILEAK VEN = 5.5V -1 +1 µA
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.
MAX4987AE/MAX4987BE
Overvoltage-Protection Controller
with USB ESD Protection
_______________________________________________________________________________________ 3
Note 2: All timing is specified using 20% and 80% levels, unless otherwise noted.
ELECTRICAL CHARACTERISTICS (continued)
(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
Switch Turn-On Time tON VUVLO < VIN < VOVLO, RLOAD = 100Ω,
from 10% to 90% of VOUT 3ms
Switch Turn-Off Time tOFF VIN < VUVLO or VIN > VOVLO to internal
switch off, RLOAD = 100Ω10 µs
Current-Limit Turn-Off Time tBLANK Overcurrent fault to internal switch off 10 µs
Autoretry Time tRETRY From overcurrent fault to internal switch
turn-on 30 ms
THERMAL PROTECTION
Thermal Shutdown TSHDN 150 °C
Thermal-Shutdown Hysteresis 40 °C
ESD PROTECTION
Human Body Model ±15
IEC 61000-4-2 Air Gap ±15CD+ and CD-
IEC 61000-4-2 Contact ±6
kV
All Other Pins Human Body Model ±2 kV
IN SUPPLY CURRENT
vs. IN VOLTAGE
MAX4987AE/BE toc01
0
10
30
20
60
70
50
40
80
IN SUPPLY CURRENT (μA)
21014618 22 26
IN VOLTAGE (V)
MAX4987AE
0
60
40
20
80
100
120
140
160
180
200
-40 10-15 35 60 85
SWITCH ON-RESISTANCE
vs. TEMPERATURE
MAX4987AE/BE toc02
TEMPERATURE (°C)
RON (mΩ)
0.990
0.996
0.994
0.992
0.998
1.000
1.002
1.004
1.006
1.008
1.010
-40 10-15 356085
NORMALIZED UVLO THRESHOLD
vs. TEMPERATURE
MAX4987AE/BE toc03
TEMPERATURE (°C)
NORMALIZED UVLO THRESHOLD (V)
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
MAX4987AE/MAX4987BE
Overvoltage-Protection Controller
with USB ESD Protection
4 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
0.990
0.996
0.994
0.992
0.998
1.000
1.002
1.004
1.006
1.008
1.010
-40 10-15 356085
NORMALIZED OVLO THRESHOLD
vs. TEMPERATURE
MAX4987AE/BE toc04
TEMPERATURE (°C)
NORMALIZED OVLO THRESHOLD (V)
0.80
0.92
0.88
0.84
0.96
1.00
1.04
1.08
1.12
1.16
1.20
-40 10-15 356085
NORMALIZED CURRENT LIMIT
vs. TEMPERATURE
MAX4987AE/BE toc05
TEMPERATURE (°C)
CURRENT LIMIT (%)
0
2.0
1.0
3.0
4.0
5.0
-40 85
TURN-ON TIME
vs. TEMPERATURE
MAX4987AE/BE toc06
TEMPERATURE (°C)
TURN ON TIME (ms)
10-15 35 60
20.0
30.0
25.0
40.0
35.0
45.0
50.0
-40 85
DEBOUNCE TIME
vs. TEMPERATURE
MAX4987AE/BE toc07
TEMPERATURE (°C)
DEBOUNCE TIME (ms)
10-15 35 60
UNDERVOLTAGE FAULT RESPONSE
MAX4987AE/BE toc10
4μs/div
VIN
2V/div
5
2
0
0
0
VOUT
2V/div
IOUT
1A/div
VACOK
5V/div
POWER-UP RESPONSE
MAX4987AE/BE toc08
10ms/div
VIN
5V/div
VOUT
5V/div
IOUT
1A/div
VACOK
5V/div
OVERVOLTAGE FAULT RESPONSE
MAX4987AE/BE toc09
2μs/div
VIN
5V/div
8V
5V
8V
5V
0
0
0
VOUT
5V/div
IOUT
1A/div
VACOK
5V/div
SHORT-CIRCUIT FAULT RESPONSE
MAX4987AE/BE toc11
10μs/div
VIN
5V/div
0
0
0
0
VOUT
5V/div
IOUT
1A/div
VACOK
5V/div
CIN = 100μF
MAX4987AE/MAX4987BE
Overvoltage-Protection Controller
with USB ESD Protection
_______________________________________________________________________________________ 5
Pin Description
PIN NAME FUNCTION
1IN
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.
2 CD+ USB Data Line
3 GND Ground
4 CD- USB Data Line
5V
CC Positive Supply-Voltage Input. VCC is required only when USB signals are present.
6EN Enable Active-Low Input. Drive EN low to enable the switch. Drive EN high to disable the switch.
7ACOK
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.
8 OUT Output Voltage. Output of internal switch.
EP EP Exposed Pad. Connect exposed pad to ground. Do not use EP as a sole ground connection.
OVERCURRENT
FAULT
IN
CD+
CD-
VCC
CHARGE
PUMP
CONTROL
LOGIC
MAX4987AE/
MAX4987BE
ACOK
VBG
REFERENCE
+
-
+
-
OV
UV
EN
EN
OUT
GND
Functional Diagram
MAX4987AE/MAX4987BE
Detailed Description
The MAX4987AE/MAX4987BE are overvoltage protec-
tion 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 over-
voltage 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 inter-
nal nFET switch during startup. An open-drain active-
low logic output is available to signal that a successful
power-up has occurred.
Device Operation
The MAX4987AE/MAX4987BE have an internal oscilla-
tor 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
< VUVLO or if VIN > VOVLO, 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.
Internal nFET Switch
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.
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
6 _______________________________________________________________________________________
UVLO
OVLO
tINDBC
tON
IN
OUT
ACOK
tINDBC
tOFF
90% VOUT
tINDBC
tOFF
10% VOUT
Figure 1. MAX4987AE/MAX4987BE Timing Diagram
Overvoltage Lockout (OVLO)
The MAX4987AE/MAX4987BE have a 6.15V (typ) over-
voltage threshold (OVLO). When VIN is greater than
VOVLO, ACOK is high impedance.
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 shut-
down after the junction temperature cools by +40°C (typ).
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 induc-
tance due to long lead length, take care to prevent over-
shoots due to the LC tank circuit and provide protection if
necessary to prevent exceeding the absolute maximum
rating on IN.
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 61000-4-
2 ESD events.
Human Body Model
Figure 3 shows the Human Body Model, and Figure 4
shows the current waveform it generates when dis-
charged into a low impedance. This model consists of
a 100pF capacitor charged to the ESD voltage of inter-
est, that is then discharged into the device through a
1.5kΩresistor.
IEC 61000-4-2
The IEC 61000-4-2 standard covers ESD testing and per-
formance of finished equipment. It does not specifically
refer to integrated circuits. The MAX4987AE/ MAX4987BE
MAX4987AE/MAX4987BE
Overvoltage-Protection Controller
with USB ESD Protection
_______________________________________________________________________________________ 7
nFET SWITCH
ON
nFET SWITCH
ON
SWITCH OFF
CURRENT
THROUGH
nFET SWITCH ILIM
tOFF
tRETRY
Figure 2. Autoretry Timing Diagram
CHARGE CURRENT-
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Cs
100pF
RC
1MΩ
RD
1.5kΩ
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
Figure 3. Human Body ESD Test Model
IP 100%
90%
36.8%
tRL TIME
tDL
CURRENT WAVEFORM
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
Ir
10%
0
0
AMPERES
Figure 4. Human Body Current Waveform
MAX4987AE/MAX4987BE
are specified for ±15kV Air-Gap Discharge and ±6kV
Contact Discharge IEC 61000-4-2 on the CD+ and CD-
pins.
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 61000-
4-2 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.
Overvoltage-Protection Controller
with USB ESD Protection
8 _______________________________________________________________________________________
CHARGE-CURRENT-
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Cs
150pF
RC
50MΩ TO 100MΩ
RD
330Ω
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
Figure 5. IEC 61000-4-2 ESD Test Model
OVERCURRENT
FAULT
IN
CD+
CD-
OUT
VCC
CHARGE
PUMP
CONTROL
LOGIC
MAX4987AE/
MAX4987BE
ACOK
VIO
PHONE
LOAD
VBG
REFERENCE
+
-
+
-
OV
UV
EN
USB
CONNECTOR
VBUS
D+
D-
USB
TRANSCEIVER
VCC
D+
D-
GND
VCC
BATTERY
CHARGER
Typical Operating Circuit
Chip Information
PROCESS: BiCMOS
MAX4987AE/MAX4987BE
Overvoltage-Protection Controller
with USB ESD Protection
_______________________________________________________________________________________ 9
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
21-0174
2
1
B
8L TDFN, EXPOSED PAD, 2x3x0.8mm
MAX4987AE/MAX4987BE
Overvoltage-Protection Controller
with USB ESD Protection
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 is a registered trademark of Maxim Integrated Products, Inc.
SPRINGER
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.)
SYMBOL
DIMENSIONS
3.002.95 0.75
NOM.
0.70
MIN.
0.20 REF.
0.40
0.02
2.00
0.30
0.00
1.95
E
A
L
A1
D
A2
k 0.20 MIN.
PACKAGE OUTLINE
21-0174
2
2
B
8L TDFN, EXPOSED PAD, 2x3x0.8mm
8N
3.05
0.80
MAX.
0.50
0.05
2.05
0.50 BSC
e
b0.250.18 0.30
1.60
MIN. 1.75
NOM. 1.90
MAX.
E2
1.50
MIN. 1.63
NOM. 1.75
MAX.
D2
T823-1
PKG.
CODE
EXPOSED PAD PACKAGE
