MAX834EUK-T中文资料

_______________General Description

The MAX834/MAX835 micropower voltage monitors contain a 1.204V precision bandgap reference, com-parator, and latched output in a 5-pin SOT23 https://www.360docs.net/doc/0513198603.html,ing the latched output prevents deep discharge of batteries. The MAX834 has an open-drain, N-channel output driver, while the MAX835 has a push/pull output driver. Two external resistors set the trip-threshold voltage.

The MAX834/MAX835 feature a level-sensitive latch,eliminating the need to add hysteresis to prevent oscil-lations in battery-load-disconnect applications.

________________________Applications

Precision Battery Monitor Load Switching

Battery-Powered Systems Threshold Detectors

____________________________Features

o Prevents Deep Discharge of Batteries o Precision ±1.25% Voltage Threshold o Latched Output (once low, stays low until cleared)o SOT23-5 Package o Low Cost

o Wide Operating Voltage Range, +2.5V to +11V o <2μA Typical Supply Current o Open-Drain Output (MAX834)Push/Pull Output (MAX835)

MAX834/MAX835

Micropower, Latching Voltage Monitors

in SOT23-5

________________________________________________________________Maxim Integrated Products 1

__________________Pin Configuration

__________Typical Operating Circuit

19-1157; Rev 0; 12/96

______________Ordering Information

For free samples & the latest literature: https://www.360docs.net/doc/0513198603.html,, or phone 1-800-998-8800

M A X 834/M A X 835

Micropower, Latching Voltage Monitors in SOT23-52_______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(V CC = +2.5V to +11V, T A = T MIN to T MAX , unless otherwise noted. Typical values are at T A = +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.

V CC , OUT (MAX834), CLEAR to GND......................-0.3V to 12V IN, OUT (MAX835), to GND........................-0.3V to (V CC +0.3V)INPUT Current

V CC .................................................................................20mA IN.....................................................................................10mA OUT Current.......................................................................-20mA

V CC Rate of Rise .............................................................100V/μs Continuous Power Dissipation

SOT23-5 (derate 7.1mW/°C above +70°C)..................571mW Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range.............................-65°C to +150°C Lead Temperature (soldering, 10sec).............................+300°C

MAX834/MAX835

Micropower, Latching Voltage Monitors

in SOT23-5

_______________________________________________________________________________________3

ELECTRICAL CHARACTERISTICS (continued)

(V CC = +2.5V to +11V, T A = T MIN to T MAX , unless otherwise noted. Typical values are at T A = +25°C.)

Note 1:The voltage-detector output remains in the correct state for V CC down to 1.2V when V IN ≤V CC / 2.Note 2:Supply current has a monotonic dependence on V CC (see Typical Operating Characteristics ).Note 3:IN leakage current has a monotonic dependence on V CC (see Typical Operating Characteristics ).

Note 4:

The MAX834 open-drain output can be pulled up to a voltage greater than V CC , but may not exceed 11V.

__________________________________________Typical Operating Characteristics

(V CC = +5V, Typical Operating Circuit, T A = +25°C, unless otherwise noted.)

5.01.0

-60-400

100

INPUT LEAKAGE CURRENT vs. TEMPERATURE

3.5

3.02.5

2.01.54.0TEMPERATURE (°C)

I N P U T L E A K A G E C U R R E N T (n A )

-20

60804.5900

1348

9101112

INPUT LEAKAGE CURRENT vs. INPUT VOLTAGE

2010307080

V IN (V)I N P U T L E A K A G E C U R R E N T (n A )

405060 4.5

1348

9101112

SUPPLY CURRENT vs. SUPPLY VOLTAGE

1.5

1.00.5

2.04.0V CC (V)

S U P P L Y C U R R E N T (μA )

2.5

3.03.5

2.4 2.8

3.2 3.6

SUPPLY CURRENT vs. INPUT VOLTAGE

V IN (V)

S U P P L Y C U R R E N T (μA )

1.221

0.40.8 2.04

1.6120

3489101112SUPPLY CURRENT vs. INPUT VOLTAGE

5432161011V IN (V)S U P P L Y C U R R E N T (μA )

256

7789 6.0

2.0

-60-40020100

PROGRAMMED TRIP VOLTAGE

vs. TEMPERATURE

3.22.82.43.65.25.6TEMPERATURE (°C)

T R I P V O L T A G E (V )

-204060804.04.44.8

M A X 834/M A X 835

Micropower, Latching Voltage Monitors in SOT23-54_______________________________________________________________________________________

013489101112

MAX835

OUTPUT SHORT-CIRCUIT

SOURCE CURRENT vs. SUPPLY VOLTAGE

V CC (V)

S H O R T -C I R C U I T C U R R E N T (m A )2

16040

-60

-40020100

SUPPLY VOLTAGE FALLING TO OUT PROPAGATION DELAY vs. TEMPERATURE

1301201101009080706050140TEMPERATURE (°C)

P R O P A G A T I O N D E L A Y (μs )

-204060801501000

01348

9101112

MAX835

OUTPUT RISE TIME vs. SUPPLY VOLTAGE

300

200100400800900V CC (V)

R I S E T I M E (n s )

5006007002.5

9101112

OUTPUT FALL TIME vs. SUPPLY VOLTAGE

1.51.0

0.5

2.0V CC (V)

F A L L T I M E (μs )2

1101001k

10k

100k

0.1

100

OUTPUT LOW VOLTAGE vs. OUTPUT SINK CURRENT

OUTPUT SINK CURRENT (mA)

V O L (m V )

1101001k 10k 100k

0.1

100

MAX835

OUTPUT HIGH VOLTAGE vs. OUTPUT SOURCE CURRENT

OUTPUT SOURCE CURRENT (mA)

V C C - V O H (m V )

10250

3489101112

OUTPUT LOW VOLTAGE vs. SUPPLY VOLTAGE

150

100

200

V CC (V)V O L (m V )2

5000

134********

MAX835

OUTPUT HIGH VOLTAGE vs. SUPPLY VOLTAGE

150100

200400450V CC (V)

V C C - V O H (m V )2

25030035020

1348

9101112

OUTPUT SHORT-CIRCUIT

V CC (V)

S H O R T -C I R C U I T C U R R E N T (m A )2

_____________________________Typical Operating Characteristics (continued)

(V CC = +5V, Typical Operating Circuit, T A = +25°C, unless otherwise noted.)

MAX834/MAX835

Micropower, Latching Voltage Monitors

in SOT23-5

_______________________________________________________________________________________

_____________________________Typical Operating Characteristics (continued)

(V CC = +5V, Typical Operating Circuit, T A = +25°C, unless otherwise noted.)

110

100

1k 10k

0.1

100

OUTPUT LOW VOLTAGE vs. OUTPUT SINK CURRENT

OUTPUT SINK CURRENT (mA)

V O L (m V )

110

100

1k 10k 0.1

MAX835

OUTPUT HIGH VOLTAGE vs. OUTPUT SOURCE CURRENT

OUTPUT SOURCE CURRENT (mA)

V C C - V O H (m V )

1.50.1

-60-400

100

CLEAR TO OUT PROPAGATION DELAY

vs. TEMPERATURE

0.90.70.50.3

1.1TEMPERATURE (°C)

P R O P A G A T I O N D E L A Y (μs )

-20

1.3______________________________________________________________Pin Description

Open-Drain (MAX834) or Push/Pull (MAX835) Latched Output. OUT is active low.

OUT

Noninverting Input to the Comparator. The inverting input connects to the internal 1.204V bandgap reference.IN 4

System Supply Input

V CC 3

System Ground GND 2

Clear Input resets the latched output. With V IN > V TH , pulse CLEAR high for a minimum of 1μs to reset the output latch. Connect to V CC to make the latch transparent.CLEAR 1

FUNCTION

NAME Figure 1. Functional Diagram Figure 2. Programming the Trip Voltage (V TRIP )

M A X 834/M A X 835

Micropower, Latching Voltage Monitors in SOT23-56

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_______________Detailed Description

The MAX834/MAX835 micropower voltage monitors con-tain a 1.204V precision bandgap reference and a com-parator with an output latch (Figure 1). The difference between the two parts is the structure of the comparator output driver. The MAX834 has an open-drain, N-channel output driver that can be pulled up to a voltage higher than V CC , but less than 11V. The MAX835’s output is push/pull and can both source and sink current.

Programming the Trip Voltage (V TRIP )

Two external resistors set the trip voltage, V TRIP (Figure 2). V TRIP is the point at which the falling monitored volt-age (typically V CC ) causes OUT to go low. IN’s high input impedance allows the use of large-value resistors without compromising trip voltage accuracy. To minimize current consumption, choose a value for R2between 500k ?and 1M ?, then calculate R1 as follows:

R1 = R2 [(V TRIP / V TH ) - 1]

where V TRIP is the desired trip voltage and V TH is the threshold voltage (1.204V). The voltage at IN must be at least 1V less than V CC .

Latched-Output Operation

The MAX834/MAX835 feature a level-sensitive latch input (CLEAR), designed to eliminate the need for hys-teresis in battery undervoltage-detection applications.When the monitored voltage (V MON ) is above the pro-grammed trip voltage (V TRIP ) (as when the system bat-tery is recharged or a fresh battery is installed), pulse CLEAR low-high-low for at least 1μs to reset the output latch (OUT goes high). When V MON falls below V TRIP ,OUT goes low and remains low (even if V MON rises above V TRIP ), until CLEAR is pulsed high again with V MON > V TRIP . Figure 3 shows the timing relationship between V MON , OUT , and CLEAR.

> V TRIP

< V TRIP

V CC

OUT

V MON

Figure 3a. Timing Diagram

Figure 3b. Timing Diagram, CLEAR = V CC

MAX834/MAX835

Micropower, Latching Voltage Monitors

in SOT23-5

_______________________________________________________________________________________7

Monitoring Voltages Other than V CC

The typical operating circuit for the MAX834/MAX835monitors V CC . Voltages other than V CC can easily be monitored, as shown in Figure 4. Calculate V TRIP as in the section Programming the Trip Voltage. When monitoring voltages other than V CC , ensure that the maximum value for V MON is not exceeded:

V MON(MAX)= (V CC - 1)(R1 + R2) / R2

Load-Disconnect Switch

The circuit in Figure 5 is designed to prevent a lead-acid battery or a secondary battery such as an NiCd,from sustaining damage through deep discharge. As the battery reaches critical undervoltage, OUT switches low. Q1 and Q2 turn off, disconnecting the battery from the load. The MAX835’s latched output prevents Q1 and Q2 from turning on again as the battery voltage relaxes to its open-circuit voltage when the load disconnects.CLEAR can be connected to a pushbutton switch, an RC network, or a logic gate to reset the latch when the battery is recharged or replaced.

Figure 4. Monitoring Voltages Other than V CC

Figure 5. Load-Disconnect Switch

TRANSISTOR COUNT: 74

___________________Chip Information

M A X 834/M A X 835

Micropower, Latching Voltage Monitors in SOT23-5Maxim 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?1996 Maxim Integrated Products

Printed USA

is a registered trademark of Maxim Integrated Products.

________________________________________________________________Package Information

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