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19-2385; Rev 2; 11/02
Current-Limited Switch for Two USB Ports
General Description
The MAX1930 current-limited 70m switch with built-in fault blanking provides an accurate, preset 1.2A to 2.3A current limit, making it ideal for dual USB applications. Its low quiescent supply current (16A) and standby current (1A) conserve battery power in portable applications. The MAX1930 operates with inputs from 2.7V to 5.5V, making it ideal for both 3V and 5V systems. The MAX1930 has several 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 overload. The MAX1930 is offered in a space-saving 8-pin SO package and operates over the extended (-40C to +85C) temperature range.
Features
o Pin Compatible with TPS2010-TPS2013 o Accurate Current Limit (1.2A min, 2.3A max) o 125m (max) High-Side MOSFET o Short-Circuit and Thermal Protection o Undervoltage Lockout o 16A Quiescent Supply Current o 1A (max) Standby Supply Current o 2.7V to 5.5V Supply Range o UL Recognized: UL# E211395
MAX1930
Applications
Notebook Computers USB Ports and Hubs Docking Stations
PART MAX1930ESA
Ordering Information
TEMP RANGE -40C to +85C PIN-PACKAGE 8 SO
Pin Configuration
TOP VIEW
INPUT 2.7V TO 5.5V
Typical Operating Circuit
IN GND IN IN 1 2 8 7 OUT OUT OUT OUTNC ON OFF EN GND
OUT
OUTPUT
MAX1930
MAX1930
3 6 5 EN 4
SO
________________________________________________________________ Maxim Integrated Products
1
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Current-Limited Switch for Two USB Ports MAX1930
ABSOLUTE MAXIMUM RATINGS
IN, EN to GND ..........................................................-0.3V to +6V OUT to GND ................................................-0.3V to (VIN + 0.3V) Maximum Switch Current.........................2.3A (internally limited) OUT Short Circuit to GND ..........................................Continuous Continuous Power Dissipation (TA = +70C) 8-Pin SO (derate 5.88mW/C above +70C)................471mW Operating Temperature Range (extended) .........-40C to +85C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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 = 5V, TA = 0C to +85C, unless otherwise noted. Typical values are at TA = +25C.)
PARAMETER OPERATING CONDITION Input Voltage POWER SWITCH Switch Static Drain-Source On-Resistance Switch Turn-On Time Switch Turn-Off Time ENABLE INPUT (EN) EN High-Level Input Voltage EN Low-Level Input Voltage EN Input Current Startup Time CURRENT LIMIT Overload Output Current Short-Circuit Output Current SUPPLY CURRENT Supply Current, Low-Level Input Supply Current, High-Level Input Supply Leakage Current UNDERVOLTAGE LOCKOUT Undervoltage Lockout THERMAL SHUTDOWN Thermal-Shutdown Threshold 165 C UVLO Rising edge, 100mV hysteresis 2.0 2.4 2.6 V IQ V EN = VIN = VOUT = 5.5V V EN = 0, IOUT = 0 V EN = VIN = 5.5V, VOUT = 0 Timer not running Timer running TA = +25C TA = 0C to +85C 0.002 16 35 0.01 2 15 1 25 A A A ILIMIT ISC Force VOUT to 4.5V OUT shorted to GND 1.2 1.75 1 2.3 1.5 A A VIH VIL VIN = 2.7V to 3.6V VIN = 3.7V to 5.5V VIN = 2.7V to 5.5V V EN = VIN or GND VIN = 5V, COUT = 150F from EN driven low to 50% full VOUT -1 1 2.0 2.4 0.8 +1 V V A ms TA = +25C RDS(ON) tON tOFF TA = 0C to +85C ILOAD = 400mA ILOAD = 400mA 3 VIN = 4.4V to 5.5V VIN = 4.4V to 5.5V VIN = 3V 72 80 6 70 100 125 150 200 20 s s m VIN 2.7 5.5 V SYMBOL CONDITIONS MIN TYP MAX UNITS
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Current-Limited Switch for Two USB Ports
ELECTRICAL CHARACTERISTICS
(VIN = 5V, TA = -40C to +85C, unless otherwise noted.) (Note 1)
PARAMETER OPERATING CONDITION Input Voltage POWER SWITCH Switch Static Drain-Source On-Resistance Switch Turn-On Time Switch Turn-Off Time ENABLE INPUT (EN) EN High-Level Input Voltage EN Low-Level Input Voltage EN Input Current CURRENT LIMIT Overload Output Current Short-Circuit Output Current SUPPLY CURRENT Supply Current, Low-Level Input Supply Current, High-Level Input Supply Leakage Current UNDERVOLTAGE LOCKOUT Undervoltage Lockout UVLO Rising edge, 100mV hysteresis 2.0 2.9 V IQ V EN = VIN = VOUT = 5.5V V EN = GND, IOUT = 0, timer not running V EN = VIN = 5.5V, VOUT = GND 2 25 15 A A A ILIMIT ISC Force VOUT to 4.5V OUT shorted to GND 1.2 2.3 1.5 A A VIH VIL VIN = 3V to 3.6V VIN = 3.7V to 5.5V VIN = 3V to 5.5V V EN = VIN or GND -1 2.0 2.4 0.8 +1 V V A RDS(ON) tON tOFF VIN = 4.4V to 5.5V VIN = 3V ILOAD = 400mA ILOAD = 400mA 1 125 150 200 20 m s s VIN 3.0 5.5 V SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX1930
Note 1: Specifications to -40C are guaranteed by design, not production tested.
Typical Operating Characteristics
(Circuit of Figure 2, VIN = 5V, TA = +25C, unless otherwise noted.)
QUIESCENT CURRENT vs. INPUT VOLTAGE
MAX1930 toc01
QUIESCENT CURRENT vs. TEMPERATURE
MAX1930 toc02
OFF SUPPLY CURRENT vs. TEMPERATURE
EN = IN OUT = OPEN OFF SUPPLY CURRENT (nA) 10
MAX1930 toc03
20 18 QUIESCENT CURRENT (A) 16 14 12 10 8 6 4 2 0
VEN = 0 IOUT = 0
18.0 IOUT = 0 17.5 QUIESCENT CURRENT (A) 17.0 16.5 16.0 15.5 15.0 14.5 14.0 VIN = 3V VIN = 5V
100
1
0.1
0.01 -40 -15 10 35 60 85 -40 -15 TEMPERATURE (C) 10 35 TEMPERATURE (C) 60 85
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 INPUT VOLTAGE (V)
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Current-Limited Switch for Two USB Ports MAX1930
Typical Operating Characteristics (continued)
(Circuit of Figure 2, VIN = 5V, TA = +25C, unless otherwise noted.)
OFF SWITCH CURRENT vs. TEMPERATURE
MAX1930 toc04
NORMALIZED ON-RESISTANCE vs. TEMPERATURE
MAX1930 toc05
NORMALIZED OUTPUT CURRENT vs. OUTPUT VOLTAGE
ILIMIT(1.75A)
MAX1930 toc06
1000 EN = IN VOUT = 0 OFF SWITCH CURRENT (nA) 100
1.4 1.3 1.2 NORMALIZED RON 1.1 1.0 0.9 0.8 0.7 IOUT = 850mA
1.2 NORMALIZED OUTPUT CURRENT 1.0 0.8 0.6
10
1
SHORT-CIRCUIT CURRENT 0.4 0.2 0
0.1
0.6 0.5
0.01 -40 -15 10 35 TEMPERATURE (C) 60 85
0.4 -40 -15 10 35 60 85 TEMPERATURE (C)
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 OUTPUT VOLTAGE (V)
TURN-ON TIME vs. TEMPERATURE
140 120 TURN-ON TIME (s) VIN = 3V 100 80 60 40 20 0 -40 -15 10 35 60 85 TEMPERATURE (C) VIN = 5V IOUT = 850mA COUT = 0.1F
MAX1930 toc07
TURN-OFF TIME vs. TEMPERATURE
8.5 8.0 TURN-OFF TIME (s) 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 -40 -15 10 35 60 85 TEMPERATURE (C) 0 VIN = 3V VIN = 5V 0 IOUT = 850mA COUT = 0.1F
MAX1930 toc08
CURRENT-LIMIT RESPONSE
MAX1930 toc09
160
9.0
5V VIN AC-COUPLED 500mV/div
VOUT, 5V/div
IOUT, 2A/div 4s/div
SWITCH TURN-ON TIME
MAX1930 toc10
SWITCH TURN-OFF TIME
MAX1930 toc11
STARTUP TIME (TYPICAL USB APPLICATION)
MAX1930 toc12
VOUT, 5V/div 0 VEN, 5V/div 0 0
VOUT, 5V/div
0 FULL CURRENT LIMIT CHARGES CAPACITOR
VOUT 5V/div
VEN, 5V/div 0
VEN 5V/div 0 RESISTOR LOAD CURRENT 0 SHORT-CIRCUIT CURRENT LIMIT
IOUT, 500mA/div 0 20s/div 0 1s/div
IOUT, 500mA/div
IIN 1A/div
1ms/div
4
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Current-Limited Switch for Two USB Ports
Pin Description
PIN 1 2, 3 4 5 6, 7, 8 NAME GND IN EN OUTNC OUT Ground Input. P-channel MOSFET source--connect all IN pins together and bypass with a 1F capacitor to ground. Active-Low Switch Enable Input. A logic low turns on the switch. No Connection. This pin is not internally connected and can be connected to OUT. Switch Output. P-channel MOSFET drain--connect all OUT pins together and bypass with a 0.1F capacitor to ground. FUNCTION
MAX1930
Thermal Shutdown
IN P OUT
MAX1930
P
The MAX1930 has a thermal shutdown feature. The switch turns off when the junction temperature exceeds +165C. When the MAX1930 cools 20C, the switch turns back on. If the fault short-circuit condition is not removed, the switch cycles on and off, resulting in a pulsed output.
REPLICA AMPLIFIER ON P
Applications Information
Input Capacitor
To limit the input voltage drop during momentary output short-circuit conditions, connect a capacitor from IN to GND. A 1F ceramic capacitor is adequate for most applications; however, higher capacitor values further reduce the voltage drop at the input (Figure 2).
ON
CURRENT-LIMIT AMPLIFIER 1.24V
Output Capacitor
GND
EN
Connect a 0.1F capacitor from OUT to GND. This capacitor helps to prevent inductive parasitics from pulling OUT negative during turn-off.
Layout and Thermal Dissipation
Figure 1. Functional Diagram
Detailed Description
The MAX1930 P-channel MOSFET power switch limits output current to 1.2A (min) and 2.3A (max). When the output current increases beyond the current limit (ILIMIT), the current also increases through the replica switch (IOUT / 13,000). The current-limit error amplifier compares the voltage to the internal 1.24V reference and regulates the current back to the ILIMIT (Figure 1). These switches are not bidirectional. As a result, the input voltage must be higher than the output voltage.
It is important to optimize the switch response time to output short-circuit conditions by keeping all traces as short as possible to reduce the effect of undesirable parasitic inductance. Place input and output capacitors as close as possible to the device (no more than 5mm away). All IN and OUT pins must be connected with short traces to the power bus. Wide power-bus planes provide superior heat dissipation through the MAX1930's IN and OUT pins. Under normal operating conditions, the package can dissipate and channel heat away. Calculate the maximum power dissipation as follows: P = (ILIMIT)2 RON where ILIMIT is the preset current limit (2.3A max) and RON is the on-resistance of the switch (125m max). When the output is short circuited, foldback-current-limiting activates and the voltage drop across the switch equals the input supply voltage. The power dissipated across the switch increases, as does the die tempera5
Continuous Short-Circuit Protection
The MAX1930 is a short-circuit protected switch. In the event of an output short-circuit condition, the current through the switch is foldback-current-limited to 1A continuous.
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Current-Limited Switch for Two USB Ports MAX1930
Driving Inductive Loads
INPUT 1F IN OUT OUTPUT 0.1F*
MAX1930
OVERCURRENT OUTPUT OFF ON EN GND
A wide variety of devices (mice, keyboards, cameras, and printers) can load the USB port. These devices commonly connect to the port with cables, which can add an inductive component to the load. This inductance causes the output voltage at the USB port to ring during a load step. The MAX1930 is capable of driving inductive loads, but avoid exceeding the device's absolute maximum ratings. Usually the load inductance is relatively small, and the MAX1930's input includes a substantial bulk capacitance from an upstream regulator, as well as local bypass capacitors, limiting overshoot. If severe ringing occurs due to large load inductance, clamp the MAX1930 output below 6V and above -0.3V.
*USB SPECIFICATIONS REQUIRE A HIGHER VALUE CAPACITOR.
Chip Information
Figure 2. Typical Application Circuit
ture. If the fault condition is not removed, the thermaloverload protection circuitry activates (see the Thermal Shutdown section). Wide power-bus planes connected to IN and OUT and a ground plane in contact with the device help dissipate additional heat.
TRANSISTOR COUNT: 715 PROCESS: BiCMOS
6
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Current-Limited Switch for Two USB Ports
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.)
SOICN .EPS
MAX1930
INCHES DIM A A1 B C e E H L MAX MIN 0.069 0.053 0.010 0.004 0.014 0.019 0.007 0.010 0.050 BSC 0.150 0.157 0.228 0.244 0.016 0.050
MILLIMETERS MAX MIN 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 1.27 BSC 3.80 4.00 5.80 6.20 0.40 1.27
N
E
H
VARIATIONS:
1
INCHES
MILLIMETERS MIN 4.80 8.55 9.80 MAX 5.00 8.75 10.00 N MS012 8 AA 14 AB 16 AC
TOP VIEW
DIM D D D
MIN 0.189 0.337 0.386
MAX 0.197 0.344 0.394
D C
A e B A1
0 -8 L
FRONT VIEW
SIDE VIEW
PROPRIETARY INFORMATION TITLE:
PACKAGE OUTLINE, .150" SOIC
APPROVAL DOCUMENT CONTROL NO. REV.
21-0041
B
1 1
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 7 (c) 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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