Datasheet

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General Description

The MAX1823 is a dual, current-limited switch with

autoreset specifically made for USB applications. The

autoreset feature latches the switch off if the output is

shorted, saving system power. The switch reactivates

when the short circuit is removed. Each channel is guar-

anteed to supply 720mA and meet USB specifications.

Low quiescent supply current (50µA) and standby current

(3µA) conserve battery power in portable applications.

The MAX1823 has multiple safety features to ensure

that the USB port is protected. Built-in thermal-overload

protection limits power dissipation and junction temper-

ature. Accurate internal current-limiting circuitry pro-

tects the input supply against both overload and

short-circuit conditions. Independent fault signals

(FAULTA and FAULTB) notify the microprocessor (µP)

when a thermal-overload, current-limit, undervoltage-

lockout (UVLO), or short-circuit fault occurs. A 20ms

fault-blanking feature ignores momentary faults, such

as those caused when hot swapping a capacitive load,

preventing false alarms to the host system. The

MAX1823A/MAX1823B also block reverse current (cur-

rent from OUT_ to IN_) while in shutdown.

The MAX1823 is available in a space-saving 10-pin

µMAX package. The MAX1823/MAX1823A are enabled

with an active-low signal, and the MAX1823B/MAX1823H

are enabled with an active-high signal. For a single ver-

sion of this device, refer to the MAX1946 data sheet. For

a triple version, refer to the MAX1940 data sheet.

Applications

USB Ports and Hubs

Notebook and Desktop Computers

PDAs and Palmtop Computers

Docking Stations

Features

♦ Dual USB Switch in Tiny 10-Pin µMAX Package

♦ Autoreset Feature Saves Power

♦ Guaranteed 720mA Load per Channel

♦ Built-In 20ms Fault Blanking

♦ Compliant to USB Specification

♦ Blocks Reverse Current in Shutdown

(MAX1823A/MAX1823B)

♦ 4V to 5.5V Input Voltage Range

♦ Independent Shutdown Control

(MAX1823/MAX1823A—Active Low)

(MAX1823B/MAX1823H—Active High)

♦ Independent FAULT Indicator Outputs

♦ Thermal-Overload Protection

♦ 50µA Quiescent Current (Both Switches On)

♦ 3µA Standby Current

♦ UL Recognized

MAX1823/MAX1823A/MAX1823B/MAX1823H

Dual USB Switch with Fault

Blanking and Autoreset

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

Typical Operating Circuit

19-1903; Rev 3; 10/03

PART TEMP RANGE PIN-PACKAGE

MAX1823EUB -40°C to +85°C 10 µMAX

MAX1823AEUB -40°C to +85°C 10 µMAX

MAX1823BEUB -40°C to +85°C 10 µMAX

MAX1823HEUB -40°C to +85°C 10 µMAX

Pin Configuration

ONBONB

ONAONA

GND

MAX1823

MAX1823A

FAULTB

FAULTA

INA

INB

USB

PORT A

OUTA

USB

PORT B

OUTB

INPUT

4V TO 5.5V

OUTA

GND

OUTBINB

INA

MAX1823

MAX1823A

MAX1823B

MAX1823H

µMAX

TOP VIEW

*(ONA) ONA

*(ONB) ONB

*( ) ARE FOR MAX1823B/MAX1823H.

FAULTB

FAULTA

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Summary of content (13 pages)

PAGE 1
9-1903; Rev 3; 10/03 Dual USB Switch with Fault Blanking and Autoreset Applications Features ♦ Dual USB Switch in Tiny 10-Pin µMAX Package ♦ Autoreset Feature Saves Power ♦ Guaranteed 720mA Load per Channel ♦ Built-In 20ms Fault Blanking ♦ Compliant to USB Specification ♦ Blocks Reverse Current in Shutdown (MAX1823A/MAX1823B) ♦ 4V to 5.
PAGE 2
MAX1823/MAX1823A/MAX1823B/MAX1823H Dual USB Switch with Fault Blanking and Autoreset ABSOLUTE MAXIMUM RATINGS IN, INA, INB, ONA, ONB, ONA, ONB OUTA, OUTB to GND ...........................................-0.3V to +6V FAULTA, FAULTB to GND..........................-0.3V to (VIN_ + 0.3V) MAX1823/MAX1823H, INA, IN to OUTA; INB, IN to OUTB ...................................................-0.3V to +6V MAX1823A/MAX1823B, INA, IN to OUTA; INB, IN to OUTB (when disabled, Note 3)...............
PAGE 3
Dual USB Switch with Fault Blanking and Autoreset (Circuit of Figure 1, VIN = VINA = VINB = 5V, ONA = ONB = GND (MAX1823/MAX1823A), ONA = ONB = IN (MAX1823B/MAX1823H), TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 4
MAX1823/MAX1823A/MAX1823B/MAX1823H Dual USB Switch with Fault Blanking and Autoreset ELECTRICAL CHARACTERISTICS (Circuit of Figure 1, VIN = VIN_ = VON_ = 5V (MAX1823B/MAX1823H); VIN = VIN_ = 5V, ON_ = GND (MAX1823/MAX1823A), TA = -40°C to +85°C, unless otherwise noted.) (Note 2) PARAMETER SYMBOL CONDITIONS Supply Voltage Range Switch On-Resistance MIN TYP 4.0 RON Standby Supply Current MAX UNITS 5.
PAGE 5
Dual USB Switch with Fault Blanking and Autoreset (Circuit of Figure 1, VIN = VIN_ = VON_ = 5V (MAX1823B/MAX1823H); VIN = VIN_ = 5V, ON_ = GND (MAX1823/MAX1823A), TA = -40°C to +85°C, unless otherwise noted.) (Note 2) PARAMETER SYMBOL CONDITIONS Logic Input High Voltage VIN_= 4V to 5.5V Logic Input Low Voltage VIN_= 4V to 5.5V MIN TYP MAX UNITS 0.8 V 2 V Logic Input Current V ON_ = 0V or VIN_ +1 µA FAULT_ Output Low Voltage ISINK = 1mA, VIN_ = 4V -1 0.
PAGE 6
Typical Operating Characteristics (continued) (Circuit of Figure 1, VIN = VINA = VINB = 5V, ON_ = GND (MAX1823/MAX1823A), ON_ = IN_ (MAX1823B/MAX1823H), TA = +25°C, unless otherwise noted.) SWITCH OFF-LEAKAGE vs. TEMPERATURE NORMALIZED RON 1.25 10 1 1.00 0.75 0.01 35 60 85 -40 -15 TEMPERATURE (°C) 10 35 60 3.6 VIN_ = 5V 3.4 MAX1823 toc06 -40 85 -15 VIN_ = 5V 10 35 60 85 FAULT-BLANKING TIME vs. TEMPERATURE MAX1823 toc08 3.3 VIN_ = 5.5V 3.1 2.9 22.0 2.7 VIN_ = 5.5V 21.
PAGE 7
Dual USB Switch with Fault Blanking and Autoreset AUTORESET CURRENT vs. INPUT VOLTAGE (MAX1823/MAX1823H) OVERLOAD RESPONSE INTO 2.5Ω (MAX1823/MAX1823H) AUTORESET CURRENT vs. INPUT VOLTAGE (MAX1823A/MAX1823B) MAX1823 toc15 37 AUTORESET CURRENT (mA) 40 TA = +25°C 30 20 TA = +85°C 10 MAX1823 toc14 TA = -40°C AUTORESET CURRENT (mA) 39 MAX1823 toc13 50 5V B 0 C 0 35 TA = +85°C 33 TA = +25°C 31 29 27 0 A D TA = -40°C 0 25 3.6 4.4 5.2 6.0 3.6 INPUT VOLTAGE (V) 4.4 5.2 6.
PAGE 8
MAX1823/MAX1823A/MAX1823B/MAX1823H Dual USB Switch with Fault Blanking and Autoreset Typical Operating Characteristics (continued) (Circuit of Figure 1, VIN = VINA = VINB = 5V, ON_ = GND (MAX1823/MAX1823A), ON_ = IN_ (MAX1823B/MAX1823H), TA = +25°C, unless otherwise noted.
PAGE 9
Dual USB Switch with Fault Blanking and Autoreset The MAX1823 is a dual, current-limited switch designed for USB applications. It has two independent switches, each with its own enable control input and autoreset function. Each switch has an error-flag output to notify the USB controller when the current-limit, short-circuit, undervoltage-lockout, or thermal-shutdown threshold is reached (Figure 2). The MAX1823 operates from a 4V to 5.5V input voltage range and guarantees a minimum 720mA output current.
PAGE 10
MAX1823/MAX1823A/MAX1823B/MAX1823H Dual USB Switch with Fault Blanking and Autoreset After the fault condition is removed, the FAULT_ output deasserts after a 20ms delay. Ensure that the MAX1823 has adequate input bypass capacitance to prevent glitches from triggering FAULT_ outputs. Input glitches greater than 0.2V/µs may cause erroneous FAULT_ indications. Behavior During Current Limit and Fault Blanking The MAX1823 limits switch current in three ways.
PAGE 11
Dual USB Switch with Fault Blanking and Autoreset CONDITION MAX1823 BEHAVIOR • • Output short circuit (VOUT < 1V) • • • Output overload current (VOUT > 1V) • • • Thermal fault (TJ > +160°C) • An output short circuit ramps the current to ISHORT in 2ms to 3ms, the switch shuts off, the blanking timer turns on, FAULT_ stays high, and the output current pulses at 0.35ARMS.
PAGE 12
MAX1823/MAX1823A/MAX1823B/MAX1823H Dual USB Switch with Fault Blanking and Autoreset Turn-On and Turn-Off Behavior In the absence of faults, the MAX1823’s internal switches turn on and off slowly under the control of the ON_ inputs. Transition times for both edges are provided in the Electrical Characteristics table. The slow chargepump switch drive minimizes load transients on the upstream power source. Under thermal fault and UVLO, the power device turns off rapidly (100ns) to protect the power device.
PAGE 13
Dual USB Switch with Fault Blanking and Autoreset 10LUMAX.EPS e 4X S 10 10 INCHES H ÿ 0.50±0.1 0.6±0.1 1 1 0.6±0.1 BOTTOM VIEW TOP VIEW D2 MILLIMETERS MAX DIM MIN 0.043 A 0.006 A1 0.002 A2 0.030 0.037 0.120 D1 0.116 0.118 D2 0.114 0.120 E1 0.116 0.118 E2 0.114 0.199 H 0.187 L 0.0157 0.0275 L1 0.037 REF b 0.007 0.0106 e 0.0197 BSC c 0.0035 0.0078 0.0196 REF S α 0∞ 6∞ MAX MIN 1.10 0.15 0.05 0.75 0.95 3.05 2.95 3.00 2.89 3.05 2.95 2.89 3.00 4.75 5.05 0.40 0.70 0.940 REF 0.177 0.270 0.500 BSC 0.