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19-1695; Rev 1; 7/01
Quad Voltage Monitor in MAX Package
General Description
The MAX6338 quad voltage monitor is capable of monitoring up to four supplies without any external components. A variety of factory-trimmed threshold voltages and supply tolerances are available to optimize the MAX6338 for specific applications. The selection includes input options for monitoring +5.0V, +3.3V, +3.0V, +2.5V, +1.8V, and -5.0V voltages. An additional high-input impedance comparator option can be used as an adjustable voltage monitor, general-purpose comparator, or digital level translator. Each of the monitored voltages is available with trip thresholds to support power-supply tolerances of either 5% or 10% below the nominal voltage. An internal bandgap reference ensures accurate trip thresholds across the extended (-40C to +85C) operating temperature range. The MAX6338 consumes 25A (typ) supply current and operates with supply voltages from +2.5V to +5.5V. An internal undervoltage lockout circuit forces all four digital outputs low when VCC drops below the minimum operating voltage. The four digital outputs all have weak internal pull-ups to VCC, allowing wire-ORed connection. Each input threshold voltage has an independent output. The MAX6338 is available in a 10-pin MAX package.
Features
o Monitors Four Voltages (Factory Programmed or User Adjustable) +5.0V, +3.3V, +3.0V, +2.5V, +1.8V, -5.0V (nominal) or User-Adjustable Settings o Low 25A Supply Current o Four Independent, Open-Drain, Active-Low Outputs o +2.5V to +5.5V Supply Voltage Range o Guaranteed from -40C to +85C o No External Components Required o Small 10-Pin MAX Package
MAX6338
Ordering Information
PART MAX6338_UB* TEMP. RANGE -40C to +85C PIN-PACKAGE 10 MAX
*Insert the desired letter from the Selector Guide into the blank to complete the part number.
Selector Guide
NOMINAL INPUT VOLTAGE PART IN1 (V) 5 5 5 5 5 5 5 5 5 5 Adj* Adj* 5 5 5 5 IN2 (V) 3.3 3.3 3.3 3.3 3.0 3.0 3.0 3.0 3.3 3.3 3.3 3.3 3.0 3.0 3.3 3.3 IN3 (V) 2.5 2.5 1.8 1.8 2.5 2.5 1.8 1.8 2.5 2.5 2.5 2.5 Adj* Adj* Adj* Adj* IN4 (V) Adj* Adj* Adj* Adj* Adj* Adj* Adj* Adj* 1.8 1.8 Adj* Adj* -5 -5 -5 -5 SUPPLY TOLERANCE (%) 10 5 10 5 10 5 10 5 10 5 10 5 10 5 10 5
________________________Applications
Telecommunications High-End Printers Desktop and Notebook Computers Data Storage Equipment Networking Equipment Industrial Equipment Set-Top Boxes
MAX6338AUB MAX6338BUB MAX6338CUB MAX6338DUB MAX6338EUB MAX6338FUB MAX6338GUB
Pin Configuration
TOP VIEW
IN1 1 IN2 IN3 IN4 GND 2 3 4 5 10 VCC 9 OUT1 OUT2 OUT3 OUT4
MAX6338HUB MAX6338IUB MAX6338JUB MAX6338KUB MAX6338LUB MAX6338MUB MAX6338NUB MAX6338OUB MAX6338PUB
MAX6338
8 7 6
MAX
*Adjustable voltage based on +1.23V internal threshold. External threshold voltage can be set using an external resistor-divider. Nominal input voltages for 1.8V and 2.5V are specified for 10% tolerances 1
________________________________________________________________ Maxim Integrated Products
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.
Quad Voltage Monitor in MAX Package MAX6338
ABSOLUTE MAXIMUM RATINGS
Terminal Voltage (with respect to GND) VCC ......................................................................-0.3V to +6V Output Voltages (OUT_) ...........................................-0.3V to +6V Input Voltages (IN_) (except -5V).............................-0.3V to +6V Input Voltage (-5V input) ..........................................-6V to +0.3V Continuous OUT_ Current...................................................20mA Continuous Power Dissipation (TA = +70C) 10-pin MAX (derate 5.6mW/C above +70C) ..........444mW Operating Temperature Range ...........................-40C to +85C Storage Temperature Range .............................-65C to +150C Junction Temperature ......................................................+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
(VCC = +2.5V to +5.5V, TA= -40C to +85C, unless otherwise noted. Typical values are at TA= +25C and VCC = +5V, unless otherwise noted.) (Note 1)
PARAMETER Supply Voltage Range Supply Current SYMBOL VCC ICC VCC = +3V VCC = +5V VIN_ = input threshold voltage (+1.8V, +2.5V, +3.0V, +3.3V, +5.0V) Input Current (Note 2) IIN_ VIN_ = 0 to VCC (input threshold voltage =1.23V) VIN_ = -5V (input threshold voltage = -5V) +5.0V (-5%) Threshold +5.0V (-10%) Threshold +3.3V (-5%) Threshold +3.3V (-10%) Threshold +3.0V (-5%) Threshold +3.0V (-10%) Threshold +2.5V (-10%) Threshold +1.8V (-10%) Threshold -5.0V (+5%) Threshold -5.0V (+10%) Threshold Adjustable Threshold Threshold Voltage Temperature Coefficient Threshold Hysteresis Propagation Delay VTHYST tpd VIN_ = VTH to (VTH - 50mV) or VTH to (VTH - 50mV) VCC = 5V, ISINK = 2mA Output Low Voltage Output High Voltage VOL VOH VCC = 2.5V, ISINK = 1.2mA VCC = 1V, ISINK = 50A VCC > 2.5V, ISOURCE = 6A (minimum) 0.8 x VCC VTH VTH VTH VTH VTH VTH VTH VTH VTH VTH VTH VIN decreasing VIN decreasing VIN decreasing VIN decreasing VIN decreasing VIN decreasing VIN decreasing VIN decreasing VIN increasing VIN increasing VIN decreasing 4.5 4.25 3.0 2.85 2.7 2.55 2.13 1.53 -4.75 -4.5 1.20 -0.1 -10 4.63 4.38 3.08 2.93 2.78 2.63 2.19 1.58 -4.63 -4.38 1.23 60 0.3 20 0.4 0.4 0.4 V V CONDITIONS MIN +2.5 25 35 25 TYP MAX +5.5 50 65 40 +0.1 -20 4.75 4.50 3.15 3.00 2.85 2.70 2.25 1.62 -4.50 -4.25 1.26 V V V V V V V V V V V ppm/C % s A UNITS V A
Note 1: 100% production tested at +25C. Overtemperature limits guaranteed by design. Note 2: Guaranteed by design. 2 _______________________________________________________________________________________
Quad Voltage Monitor in MAX Package
Typical Operating Characteristics
(VCC = +5V, TA = +25C, unless otherwise noted.)
MAX6338
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX6338-01
NORMALIZED THRESHOLD ERROR vs. SUPPLY VOLTAGE
MAX6338-02
NORMALIZE THRESHOLD vs. TEMPERATURE
VCC = +5V NORMALIZED THRESHOLD (%) 0
MAX6338-03
45 40 SUPPLY CURRENT (A) 35 30 25 20 15 10 2.5 3.0 3.5 4.0 4.5 5.0 TA = -40C TA = +85C TA = +25C
0.10 NORMALIZED THRESHOLD ERROR (%) 0.08 0.06 0.04 0.02 0 -0.02 -0.04 -0.06 2.5 3.0 3.5 4.0 NORMALIZED TO +5V
0.1
-0.1
-0.2
-0.3 4.5 5.0 5.5 -40 -20 0 20 40 60 80 SUPPLY VOLTAGE (V) TEMPERATURE (C)
5.5
SUPPLY VOLTAGE (V)
OUTPUT VOLTAGE LOW vs. SINK CURRENT
MAX6338-04
PROPAGATION DELAY (WITH 100mV OVERDRIVE)
MAX6338-05
PROPAGATION DELAY (WITH 20mV OVERDRIVE)
MAX6338-06
0.6 VCC = 5V OUTPUT VOLTAGE LOW (V) 0.5 0.4 0.3 TA = +85C 0.2 0.1 0 0 1 2 3 4 5 6 7 8 9 TA = -40C TA = +25C
IN_ 50mV/div
IN_ 20mV/div
OUT_ 2V/div
OUT_ 2V/div
10
10s/div
10s/div
SINK CURRENT (mA)
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3
Quad Voltage Monitor in MAX Package MAX6338
Pin Description
PIN 1 2 3 4 5 6 7 8 9 10 NAME IN1 IN2 IN3 IN4 GND OUT4 OUT3 OUT2 OUT1 VCC FUNCTION Input Voltage 1. See Selector Guide for monitored voltages. Input Voltage 2. See Selector Guide for monitored voltages. Input Voltage 3. See Selector Guide for monitored voltages. Input Voltage 4. See Selector Guide for monitored voltages. Ground Output 4. OUT4 goes low when VIN4 falls below its absolute threshold. OUT4 is open drain with a 10A internal pullup to VCC. Output 3. OUT3 goes low when VIN3 falls below its absolute threshold. OUT3 is open drain with a 10A internal pullup to VCC. Output 2. OUT2 goes low when VIN2 falls below its absolute threshold. OUT2 is open drain with a 10A internal pullup to VCC. Output 1. OUT1 goes low when VIN1 falls below its absolute threshold. OUT1 is open drain with a 10A internal pullup to VCC. Power Supply. Connect VCC to a +2.5V to +5.5V supply. An undervoltage lockout circuit forces all OUT_ pins low when VCC drops below 2.5V.
_______________Detailed Description
The MAX6338 is a low-power (25A), quad voltage monitor designed for multivoltage systems. Preset voltage options for +5.0V, +3.3V, +3.0V, +2.5V, +1.8V, and -5.0V make these quad monitors ideal for applications such as telecommunications, desktop and notebook computers, high-end printers, data storage equipment, and networking equipment. The MAX6338 has an internally trimmed threshold that minimizes or eliminates the need for external components. The four open-drain outputs have weak (10A) internal pullups to VCC, allowing them to interface easily with other logic devices. The MAX6338 can monitor power supplies with either 5% or 10% tolerance specifications, depending on the selected version. An additional high-input-impedance comparator option can be used as an adjustable voltage monitor, general-purpose comparator, or digital level translator. The weak internal pullups can be overdriven by external pullups to any voltage from 0 to +5.5V. Internal circuitry prevents current flow from the external pullup voltage to VCC. The outputs can be wire-ORed for a single "power good" signal. The MAX6338 has either one or two auxiliary inputs and two or three factory-programmed threshold voltages, or four fixed voltages. The inverting input of all compara4
tors is connected to a 1.23V bandgap reference for all positive voltages. The noninverting terminals are accessible through internal resistive voltage-dividers with preset factory threshold voltages. In the case of auxiliary (AUX) input, the positive terminal of the comparator is accessible directly for setting the threshold for the monitored voltage. When any of the inputs (IN1-IN4) are higher than the threshold level, the output is high. The output goes low as the input drops below the threshold voltage monitor. The undervoltage lockout circuitry remains active and the outputs remain low with VCC down to 1V (Figure 1).
Applications Information
Hysteresis
When the voltage on one comparator input is at or near the voltage on the other input, ambient noise generally causes the comparator output to oscillate. The most common way to eliminate this problem is through hysteresis. When the two comparator input voltages are equal, hysteresis causes one comparator input voltage to move quickly past the other, thus taking the input out of the region where oscillation occurs. Standard comparators require hysteresis to be added through the use of external resistors. The external resistive network usually provides a positive feedback to the input in order to cause a jump in the threshold voltage when
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Quad Voltage Monitor in MAX Package MAX6338
VCC
MAX6338M/N/O/P
IN1
OUT1
VCC
IN2 OUT2
VCC
IN3* (AUX)*
OUT3
VCC
IN4 (-5V)
OUT4
VREF
REFERENCE VCC UNDERVOLTAGE LOCKOUT
*SEE AUXILIARY INPUT SECTION.
Figure 1. MAX6338 Functional Diagram
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5
Quad Voltage Monitor in MAX Package MAX6338
+5V 0.1F* VCC V1 V2 V3 V4 IN1 IN2 IN3 IN4 OUT1 OUT2 OUT3 IN2 MAX6338 VIN (+5V) IN1
+5V
VCC OUT1 MAX6338
D1
D2 OUT2 D3
IN3
OUT3 D4
OUT4 GND
IN4 GND
OUT4
*OPTIONAL
Figure 2. Quad Undervoltage Detector with LED Indicators
Figure 3. VCC Bar Graph Monitoring
VTH1 = 1 + R2 VREF R1
(
)
+5V VCC IN1 R1 IN2 MAX6338HUB OUT1 OUT1
VREF = 1.23V
R2
VTH1
OUT2 OUT1
INPUT IN3 R4 IN4 R3 VTH4 = 1 + R4 VREF R3 GND OUT VTH OUT4 OUT3 OUT4 VTH4
(
)
Figure 4. Window Detection
Figure 5. Output Response of Window Detector Circuit
output toggles in one direction or the other. These resistors are not required when using the MAX6338 because hysteresis is built into the device. MAX6338 hysteresis is typically 0.3%.
The MAX6338 can also be used in applications such as system supervisory monitoring, multivoltage level detection, and VCC bar graph monitoring (Figure 3).
Window Detection
A window detector circuit uses two auxiliary inputs in a configuration such as the one shown in Figure 4. External resistors R1-R4 set the two threshold voltages (VTH1 and VTH4) of the window detector circuit. Window width (VTH) is the difference between the threshold voltages (Figure 5).
Undervoltage Detection Circuit
The open-drain outputs of the MAX6338 can be configured to detect an undervoltage condition. Figure 2 shows a configuration where a low at a comparator output indicates an undervoltage condition, which in turn causes an LED to light.
6
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Quad Voltage Monitor in MAX Package
VINTH
Unused Inputs
The unused inputs (except the auxiliary) are internally connected to ground through the lower resistors of the threshold-setting resistor pairs. The auxiliary (AUX) input, however, must be connected to either ground or VCC if unused.
MAX6338
R1
Power-Supply Bypassing and Grounding
R2
The MAX6338 operates from a single +2.5V to +5.5V supply. In noisy applications, connect a 0.1F capacitor on the supply voltage line close to V CC pin for bypassing.
VREF = 1.23V R1 = R2
INTH ( V1.23 - 1)
Chip Information
TRANSISTOR COUNT: 620 PROCESS: BiCMOS
Figure 6. Setting the Auxiliary Monitor
Auxiliary Input
The adjustable voltage monitor is comparable to an internal reference of 1.23V as shown in Figure 6. To set the desired trip level of monitored supply, V INTH , choose: R1 = R2 [(VINTH / 1.23) - 1)]. For example, for a voltage detection at 4.5V (assume R2 = 100k), R1 = 265k.
Typical Operating Circuit
+2.5V TO +5.5V (MAY BE ONE OF THE MONITORED VOLTAGES)
VCC IN1 SUPPLIES TO BE MONITORED IN2 IN3 IN4 GND MAX6338 OUT1 OUT2 OUT3 OUT4 SYSTEM LOGIC P
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7
Quad Voltage Monitor in MAX Package MAX6338
Package Information
10LUMAX.EPS 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.
8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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