Document
19-1865; Rev 0; 11/00
Dual USB Switch with Fault Blanking
General Description
The MAX1812 is a dual current-limited switch specifically made for USB applications. Each channel is guaranteed to supply 500mA and meets USB specifications. The MAX1812’s low quiescent supply current (45µA) and shutdown current (3µA) conserve battery power in portable applications. The MAX1812 has multiple safety features to ensure that the USB port is protected. Built-in thermal-overload protection limits power dissipation and junction temperature. The device also has accurate internal current-limiting circuitry to protect the input supply against both overload and short-circuit conditions. Independent fault signals (FAULTA and FAULTB) notify the microprocessor when a thermal-overload, current limit, undervoltage lockout, or short-circuit fault occurs. A 20ms fault-blanking feature enables the circuit to ignore momentary faults, such as those caused when hot-swapping a capacitive load, thereby preventing false alarms to the host system. The MAX1812 is available in a space-saving 10-pin µMAX package. For single versions of this device, refer to the MAX1693, MAX1694, and MAX1607 data sheets.
Features
o Dual USB Switch in Tiny 10-Pin µMAX Package o Guaranteed 500mA Load per Channel o Built-In 20ms Fault Blanking o Compliant to USB Specifications o +4.0V to +5.5V Input Voltage Range o 45µA Quiescent Current o 3µA Shutdown Current o Independent Shutdown Control o Independent FAULT Indicator Outputs o Thermal-Overload Protection o UL Listing Pending
MAX1812
________________________Applications
USB Ports USB Hubs Notebook Computers Desktop Computers PDAs and Palmtop Computers Docking Stations
PART MAX1812EUB
Ordering Information
TEMP. RANGE -40°C to +85°C PIN-PACKAGE 10 µMAX
Typical Operating Circuit
INA IN OUTA
Pin Configuration
TOP VIEW
USB PORT A
INPUT 4.0V TO 5.5V
INB
ONA 1
10 FAULTA 9 OUTA GND OUTB FAULTB
MAX1812
FAULTA FAULTB ONA ONB ONA ONB OUTB
INA
USB PORT B
2 3 4 5
IN INB ONB
MAX1812
8 7 6
GND
µMAX
________________________________________________________________ Maxim Integrated Products
1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Dual USB Switch with Fault Blanking MAX1812
ABSOLUTE MAXIMUM RATINGS
IN, INA, INB, ONA, ONB, OUTA, OUTB to GND......-0.3V to +6V FAULTA, FAULTB to GND .........................-0.3V to (VIN_ + 0.3V) INA, IN to OUTA; INB, IN to OUTB..........................-0.3V to +6V OUTA, OUTB Maximum Continuous Switch Current (per channel, internally limited) .........................................1.2A FAULTA, FAULTB Current .................................................20mA Continuous Power Dissipation (TA = +70°C) 10-Pin µMAX (derate 5.6mW/°C above +70°C) ............444mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°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.
ELECTRICAL CHARACTERISTICS
(VIN = VINA = VINB = 5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C) (Note 1)
PARAMETER Supply Voltage Range Switch On-Resistance Standby Supply Current Quiescent Supply Current RON TA = +25°C, each switch TA = -40°C to +85°C, each switch Both switches disabled Both switches enabled, IOUTA = IOUTB = 0 Switches disabled, VOUTA = VOUTB = 0, TA = +25°C Switches disabled, VOUTA = VOUTB = 0, TA = -40°C to 85°C Undervoltage Lockout Threshold Continuous Load Current Continuous Current Limit Short-Circuit Current Limit Short-Circuit Detect Threshold Continuous Current-Limit Blanking Timeout Period Short-Circuit Blanking Timeout Period Turn-On Delay Output Rise Time Turn-Off Delay from ON Output Fall Time Thermal Shutdown Threshold ILIM ISHORT VIN_ - VOUT_ = 0.5V VOUT_ = 0 (IOUT pulsing) (Note 2) From continuous current-limit condition to FAULT_ assertion From short-circuit current-limit condition to FAULT_ assertion ROUT = 10Ω, COUT = 1µF does not include rise time (from ON_ to 10% of VOUT) ROUT = 10Ω, COUT = 1µF, from 10% to 90% of VOUT ROUT = 10Ω, COUT = 1µF does not include fall time (from ON_ to 90% of VOUT) COUT = 1µF, ROUT = 10Ω, from 90% to 10% of VOUT 15°C hysteresis 10 7.5 0.5 UVLO Rising edge, 3% hysteresis 3.0 500 0.6 0.8 0.9 1.2 0.35 1 20 18 1.2 2.5 0.8 2.5 160 3 35 35 4.0 1.2 1.6 3.4 3 45 0.002 SYMBOL CONDITIONS MIN 4.0 75 TYP MAX 5.5 105 135 10 100 1 µA 10 3.8 V mA A A.