MIC842LYC5_技术文档

MIC841/2

Micrel

MIC841/842

Comparator with Reference

General Description

The MIC841 and MIC842 are micropower, precision voltage

comparators with an on-chip voltage reference.

Teeny™

Both devices are intended for voltage monitoring applications.

Externalresistorsareusedtosetthevoltagemonitorthreshold.

When the threshold is crossed, the outputs switch polarity.

Features

• Optimized for PDAs, cellular telephones, pagers,

and other battery-powered devices

• Output can be pulled up to 6V regardless of supply

voltage (841NBC5 only)

• High ±1.25% voltage threshold accuracy

• Built in hysteresis for noise suppression

(MIC842)

• Extremely low 1.5µA typical supply current

• Immune to brief input transients

• Teeny™ 5-lead SC-70 package

The MIC842 incorporates a voltage reference and comparator

with fixed internal hysteresis; two external resistors are used to

set the switching threshold voltage. The MIC841 provides a

similar function with user adjustable hysteresis; this part re-

quires three external resistors to set the upper and lower

thresholds (the difference between the threshold voltages

being the hysteresis voltage).

Both the MIC841 and MIC842 are available with push-pull or

open-drain output stage. The push-pull output stage is config-

uredeitheractivehighoractivelow;theopen-drainoutputstage

is only configured active high.

Applications

• PDAs

• Pagers

• Cordless phones

• Consumer electronics

• Embedded controllers

• Personal electronics

Supply current is extremely low (1.5µA, typical), making it ideal

for portable applications.

The MIC841/2 is supplied in Micrel’s Teeny™ 5-lead SC-70

package.

Data sheets and support documentation can be found on

Micrel’s web site at www.micrel.com.

Typical Application

V_IN

V_DD

MIC841

V_IN

V_DD

5

3

1

4

2

R1

V_OUT

VDD OUT

LTH

MIC842

V_LTH> V_HTH

V_REF= 1.24V

1.5V ≤ V_DD≤ 5.5V

V_OUT

VDD

OUT

5

4

2

HTH GND

R2

R3

R1

V_REF= 1.24V

1.5V ≤ V_DD≤ 5.5V

INP

GND

1

R2

Threshold Detection with Hysteresis Set by a Third

External Resistor

Threshold Detector with Internal Fixed Hysteresis

Teeny™ is a trademark of Micrel, Inc.

Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

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MIC841/2

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Ordering Information

Hysteresis

Adjustment

Output

Stage

Output

Function

Part Number

MIC841HBC5

MIC841LBC5

MIC841NBC5

MIC842HBC5

MIC842LBC5

MIC842NBC5

MIC841HYC5

Marking

B13

Temperature Range

–40°C to +85°C

Package

External

Internal

External

Push Pull

Open Drain

Push Pull

Open Drain

Push Pull

Active High

Active Low

Active High

Active Low

Active High

SC-70-5

B14

B15

B16

B17

B18

B13

SC-70-5

Pb-Free

MIC841LYC5

MIC841NYC5

MIC842HYC5

MIC842LYC5

MIC842NYC5

B14

B15

B16

B17

B18

External

Internal

Push Pull

Open Drain

Push Pull

Active Low

Active High

Active Low

Active High

–40°C to +85°C

SC-70-5

Pb-Free

SC-70-5

Pb-Free

SC-70-5

Pb-Free

Push Pull

SC-70-5

Pb-Free

Open Drain

SC-70-5

Pb-Free

MIC841/2

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MIC841/2

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Pin Configuration

NC GND INP

LTH GND HTH

3

2

1

3

2

1

Bxx

4

5

4

5

OUT

VDD

OUT

VDD

MIC841

SC-70-5 (C5)

MIC842

SC-70-5 (C5)

Pin Description MIC841

Pin Number

Pin Name

Pin Function

High-Voltage Threshold (Input): Analog input to a comparator. This is the

1

HTH

voltage input assigned to detect a high-voltage condition. When the level on

this pin exceeds V_REF, OUT is asserted and the condition is latched until

V_LTH< V_REF

.

2

3

GND

LTH

Ground.

Low-Voltage Threshold (Input): Analog input to a comparator. This is the

voltage input assigned to detect a low voltage condition. When the level on

this pin falls below V_REF, OUT is de-asserted and the condition is latched

until V_HTH> V_REF

.

4

OUT (“N” Version)

OUT (“H” Version)

OUT (“L” Version)

V_DD

Output: Active-high, open-drain output. This output is de-asserted and

latched when V_LTH<V_REF, indicating a low voltage condition. This state

remains latched until V_HTH> V_REF

.

Output: Push-pull output. This output is de-asserted and latched when V_LTH

< V_REF, indicating a low voltage condition. This state remains latched until

V_HTH> V_REF

.

Output: Push-pull output. This output is asserted and latched when

V_LTH< V_REF, indicating a low voltage condition. This state remains latched

until V_HTH> V_REF

.

5

Power Supply (Input): Independent supply input for internal circuitry.

Pin Description MIC842

Pin Number

Pin Name

Pin Function

1

INP

Input: Analog input to the comparator. When V_INP> V_REF+ V_HYST, V_OUTis

asserted, and the condition is held until V_INP< V_REF

.

2

3

4

GND

NC

Ground.

No Connect.

OUT (“N” Version)

Output: Active-high, open-drain output. This output is de-asserted when

V_INP< V_REF, indicating a low voltage input. The output is asserted when

V_INP> V_REF+ V_HYST

.

OUT (“H” Version)

OUT (“L” Version)

V_DD

Output: Push-pull output. This output is de-asserted and latched when

V_INP< V_REF, indicating a low voltage condition. This state remains latched

until V_INP> V_REF+ V_HYST

.

Output: Push-pull output. This output is asserted and latched when

V_INP< V_REF, indicating a low voltage condition. This state remains latched

until V_INP> V_REF+ V_HYST

.

5

Power Supply (Input): Independent supply input for internal circuitry.

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MIC841/2

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Absolute Maximum Ratings⁽¹⁾

Operating Ratings⁽²⁾

Supply Voltage (V ) ..................................... –0.3V to +7V

Supply Voltage (V ) .................................. +1.5V to +5.5V

DD

Input Voltage (V ) ......................................................+7V

Input Voltage (V ) ......................................... –0.3V to 6V

INP

Output Current (I

) .................................................20mA

Ambient Temperature Range (T ) ............. –40°C to +85°C

OUT

A

Storage Temperature (T ) ....................... –65°C to +150°C

Junction Temperature (T ) ....................... Internally Limited

S

J

ESD Rating, Note 3 ...................................................... 1kV

Package Thermal Resistance (θ ) ......................450°C/W

JA

Electrical Characteristics⁽⁴⁾

1.5V ≤ V_DD≤ 5.5V; T_A= +25°C, bold values indicate –40°C ≤ T_A≤ +85°C; unless noted.

Symbol

I_DD

Parameter

Condition

Min

Typ

1.5

Max

3

Units

µA

nA

V

Supply Current

output not asserted

I_INP

Input Leakage Current

Reference Voltage

0.005

1.240

20

10

V_REF

0°C to 85°C

1.225

1.219

8

1.256

1.261

35

–40°C to 85°C

V

V_HYST

t_D

Hysteresis Voltage, (Note 5)

MIC842 only

mV

µs

V

Propagation Delay

V_INP= 1.352V to 1.128V

V_INP= 1.143V to 1.367V

I_SINK= 1.6mA, V_DD≥ 1.6V

I_SINK= 100µA, V_DD≥ 1.2V

I_SOURCE= 500µA, V_DD≥ 1.6V

I_SOURCE= 50µA, V_DD≥ 1.2V

12

8

V_OUT

Output Voltage-Low

Output Voltage-High

0.05

0.3

0.4

(Note 6)

0.005

0.99V_DD

V

Notes:

1. Exceeding the absolute maximum rating may damage the device.

2. The device is not guaranteed to function outside its operating rating.

3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.

4. Specification for packaged product only.

5.

6.

V

= V

+ V

.

HYST

HTH

REF

operating range is 1.5V to 5.5V. Output is guaranteed to be de-asserted down to V = 1.2V.

DD

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Block Diagrams

V_DD

V_IN

V_DD

5

V_IN

5

Low-Voltage

Detect

High-Voltage

Detect

INP

LTH

V_TH

1

V_LTH

3

OUT

R

S

Q

4

High-Voltage

Detect

HTH

V_HTH

1

1.24V

Bandgap

Reference

MIC842H

1.24V

2

Bandgap

GND

Reference

MIC841H

2

GND

V_DD

V_IN

5

V_DD

V_IN

Low-Voltage

Detect

5

High-Voltage

Detect

LTH

INP

V_LTH

V_TH

3

1

OUT

R

S

Q

OUT

4

High-Voltage

Detect

4

HTH

V_HTH

1

1.24V

Bandgap

Reference

1.24V

MIC842L

Bandgap

2

GND

Reference

MIC841L

2

GND

V_DD

5

V_IN

V_DD

Low-Voltage

V_IN

Detect

5

High-Voltage

Detect

LTH

INP

V_LTH

3

OUT

R

S

Q

V_TH

OUT

1

4

High-Voltage

Detect

4

HTH

V_HTH

1

1.24V

Bandgap

Reference

1.24V

Bandgap

MIC842N

Reference

2

GND

MIC841N

2

GND

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MIC841/2

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Once the desired trip points are determined, set the V

Applications Information

Output

IN(HI)

threshold first.

For example, use a total of 1MΩ = R1 + R2 + R3. For a typical

single-cell lithium ion battery, 3.6V is a good “high threshold”

because at 3.6V the battery is moderately charged. Solving

for R3:

The MIC841N and MIC842N outputs are an open-drain

MOSFET, so most applications will require a pull-up resistor.

The value of the resistor should not be too large or leakage

effectsmaydominate. 470kΩ isthemaximumrecommended

value. Note that the output of “N” version may be pulled up as

high as 6V regardless of the ICs supply voltage. The “H” and

“L” versions of the MIC841 and MIC842 have a push-pull

1MΩ

V

= 3.6V = 1.24

IN(HI)

R3

output stage, with a diode clamped to V . Thus, the maxi-

DD

R3 = 344kΩ

Once R3 is determined, the equation for V

todetermineR2. Asinglelithium-ioncell, forexample, should

not be discharged below 2.5V. Many applications limit the

mum output voltage of the “H” and “L” versions is V . See

DD

can be used

IN(LO)

“Electrical Characteristics.”

When working with large resistors on the input to the devices,

a small amount of leakage current can cause voltage offsets

thatdegradesystemaccuracy.Themaximumrecommended

drain to 3.1V. Using 3.1V for the V

threshold allows

IN(LO)

calculation of the two remaining resistor values.

total resistance from V to ground is 3MΩ. The accuracy of

IN

the resistors can be chosen based upon the accuracy re-

quired by the system. The inputs may be subjected to

voltages as high as 6V steady-state without adverse effects

of any kind regardless of the ICs supply voltage. This applies

even if the supply voltage is zero. This permits the situation

inwhichtheIC’ssupplyisturnedoff,butvoltageisstillpresent

on the inputs. See “Electrical Characteristics.”

1MΩ

V

= 3.1V = 1.24

IN(LO)

R2 + 344k

R2 = 56kΩ

1MΩ − R2 −R3 = R1

(

)

R1= 600kΩ

Programming the MIC841 Thresholds

The accuracy of the resistors can be chosen based upon the

accuracy required by the system.

The low-voltage threshold is calculated using:

Programming the MIC842 Thresholds

R1+R2 +R3

V

= V

REF

The voltage threshold is calculated using:

IN(LO)

R2 +R3

R1+R2

V

= V_REF

The high-voltage threshold is calculated using:

IN(LO)

R2

R1+R2 +R3

where:

V

= V

REF

IN(HI)

R3

where, for both equations:

= 1.240V

V

= 1.240V

REF

V_IN

V

REF

MIC842N

VDD OUT

470k

R1

R2

In order to provide the additional criteria needed to solve for

the resistor values, the resistors can be selected such that

V_OUT

5

1

4

2

INP

GND

they have a given total value, that is, R1 + R2 + R3 = R

.

TOTAL

A value such as 1MΩ for R

is a reasonable value

TOTAL

because it draws minimum current but has no significant

effect on accuracy.

V_IN

V_DD

Figure 2. MIC842 Example Circuit

MIC841N

In order to provide the additional criteria needed to solve for

the resistor values, the resistors can be selected such that

470k

604k

5

3

1

4

2

R1

R2

R3

V_OUT

VDD OUT

LTH

1%

they have a given total value, that is, R1 + R2 = R

. A

TOTAL

56k

1%

HTH GND

valuesuchas1MΩ forR

isareasonablevaluebecause

TOTAL

it draws minimum current but has no significant effect on

accuracy.

340k

1%

Figure 1. MIC841 Example Circuit

MIC841/2

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September 2004

MIC841/2

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Input Transients

The MIC841/2 is inherently immune to very short negative-

going “glitches.” Very brief transients may exceed the V

IN(LO)

threshold without tripping the output.

As shown in Figure 3, the narrower the transient, the deeper

the threshold overdrive that will be ignored by the MIC841/2.

The graph represents the typical allowable transient duration

for a given amount of threshold overdrive that will not gener-

ate an output.

Input Transient

Response

140

120

100

80

60

40

20

0

1

10

100

1000

–V

RESET COMP. OVERDRIVE, V

(mV)

LTH

REF

Figure 3. Input Transient Response

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MIC841/2

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Package Information

0.65 (0.0256) BSC

1.35 (0.053) 2.40 (0.094)

1.15 (0.045) 1.80 (0.071)

2.20 (0.087)

1.80 (0.071)

DIMENSIONS:

MM (INCH)

1.00 (0.039) 1.10 (0.043)

0.80 (0.032) 0.80 (0.032)

0.18 (0.007)

0.10 (0.004)

0.00 (0.000)

0.30 (0.012)

0.15 (0.006)

0.30 (0.012)

0.10 (0.004)

SC-70 (C5)

MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL + 1 (408) 944-0800 FAX + 1 (408) 474-1000 WEB http://www.micrel.com

The information furnished by Micrel in this datasheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use.

Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.

Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can

reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into

the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s

use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser’s own risk and Purchaser agrees to fully indemnify

Micrel for any damages resulting from such use or sale.

MIC841/2

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September 2004


型号：	MIC842LYC5
厂家：	MICREL SEMICONDUCTOR
描述：	Comparator with Reference 比较有参考
文件：	总8页 (文件大小：65K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

MIC842LYC5 [MICREL]

相关型号：

MIC842LYC5-T5

MIC842LYC5-TR

MIC842LYMT

MIC842LYMT-T5

MIC842LYMT-TR

MIC842NBC5

MIC842NYC5

MIC842NYC5-T5

MIC842NYC5-TR

MIC842NYMT

MIC842NYMT-T5

MIC842NYMT-TR