AS1977_技术文档

Data Sheet

AS1976, AS1977

Ultra-Low Current, 1.8V Comparators

1 General Description

2 Key Features

ꢀ CMOS Push/Pull Output Sinks and Sources 8mA

The AS1976/AS1977 are very low-current comparators

that can operate beyond the rail voltages and are guar-

anteed to operate down to 1.8V

(AS1976)

ꢀ CMOS Open-Drain Output Voltage Extends Beyond

Low input bias current, current-limiting output circuitry,

and ultra-small packaging make these comparators

ideal for low-power 2-cell applications including power-

management and power-monitoring systems.

VCC (AS1977)

ꢀ Ultra-Low Supply Current: 200nA

ꢀ Internal Hysteresis: 3mV

The comparators are available as the standard products

listed in Table 1.

Table 1. Standard Products

ꢀ 3V-to5V Logiv-Level Translation

ꢀ Guaranteed to Operate Down to +1.8V

Model

AS1976

AS1977

Output Type

Push/Pull

Current

200nA

Open-Drain

ꢀ Input Voltage Range Operates 200mV Beyond the

Rails

The AS1976 push/pull output can sink or source current.

The AS1977 open-drain output can be pulled beyond

VCC to a maximum of 6V > VEE. This open-drain model

is ideal for use as a logic-level translator or bipolar-to-

unipolar converter.

ꢀ Crowbar Current-Free Switching

ꢀ No Phase Reversal for Overdriven Inputs

ꢀ 5-pin SOT23 Package

Large internal output drivers provide rail-to-rail output

swings with loads up to 8mA. Both devices feature built-

in battery power-management and power-monitoring cir-

cuitry.

3 Applications

The AS1976/AS1977 are available in a 5-pin SOT23

package.

The devices are ideal for battery monitoring/manage-

ment, mobile communication devices, laptops and

PDAs, ultra-low-power systems, threshold detectors/dis-

criminators, telemetry and remote systems, medical

instruments, or any other space-limited application with

low power-consumption requirements.

Figure 1. Block Diagram

5

VCC

AS1976/

AS1977

3

+

1

IN+

4

OUT

–

IN-

2

VEE

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AS1976/AS1977

Data Sheet - Pinout

4 Pinout

Pin Assignments

Figure 2. Pin Assignments (Top View)

OUT

VEE

IN+

1

2

3

5

VCC

AS1976/

AS1977

4

IN-

Pin Descriptions

Table 2. Pin Descriptions

Pin Name

Number

Description

Comparator Output

1

2

3

4

5

OUT

VEE

IN+

IN-

Negative Supply Voltage

Comparator Non-Inverting Input

Comparator Inverting Input

Positive Supply Voltage

VCC

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AS1976/AS1977

Data Sheet - Absolute Maximum Ratings

5 Absolute Maximum Ratings

Stresses beyond those listed in Table 3 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 Section 6 Electrical

Characteristics on page 4 is not implied. Exposure to absolute maximum rating conditions for extended periods may

affect device reliability.

Table 3. Absolute Maximum Ratings

Parameter

Min

Max

Units

Comments

Supply Voltage VCC to VEE

+7

V

VEE

VCC

Voltage Inputs IN+, IN-

V

- 0.3

+ 0.3

VEE

- 0.3

VCC

+ 0.3

Output Voltage AS1976, AS1978

Output Current

-50

+50

10

mA

s

Output Short-Circuit Duration

Continuous Power Dissipation

Operating Temperature Range

Storage Temperature Range

571

+85

+150

mW

ºC

Derate at 7.31mW/ºC above +70ºC

-40

-65

ºC

The reflow peak soldering temperature (body

temperature) specified is in accordance with IPC/

JEDEC J-STD-020C “Moisture/Reflow Sensitivity

Classification for Non-Hermetic Solid State

Surface Mount Devices”.

Package Body Temperature

+260

ºC

The lead finish for Pb-free leaded packages is

matte tin (100% Sn).

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AS1976/AS1977

Data Sheet - Electrical Characteristics

6 Electrical Characteristics

VCC = +5V, VEE = 0, VCM = 0, TAMB = -40 to +85ºC (unless otherwise specified). Typ values are at TAMB = +25ºC.

Table 4. AS1976/AS1977 Electrical Characteristics

Symbol

Parameter

Conditions

Inferred from the PSRR test

VCC = 1.8V

Min

Typ

Max Units

VCC

Supply Voltage Range

1.8

5.5

V

0.2

ICC

Supply Current

VCC = 5V, TAMB = +25ºC

VCC = 5V, TAMB = TMIN to TMAX

0.21

0.5

0.9

µA

Input Common-Mode

Voltage Range

VEE

- 0.2

VCC

+ 0.2

VCM

Inferred from CMRR test

V

-0.2V ≤ VCM ≤ (VCC + 0.2V),

1

5

TAMB = +25ºC ¹

VOS

Input Offset Voltage

mV

-0.2V ≤ VCM ≤ (VCC + 0.2V),

10

TAMB = TMIN to TMAX

Input-Referred

Hysteresis

-0.2V ≤ VCM ≤ (VCC + 0.2V) ²

VHB

IB

3

mV

nA

TAMB = +25ºC

0.15

1

2

Input Bias Current ³

TAMB = TMIN to TMAX

IOS

Input Offset Current

10

pA

Power-Supply

Rejection Ratio

PSRR

VCC = 1.8 to 5.5V, TAMB = +25ºC

0.05

1

mV/V

Common-Mode

Rejection Ratio

(VEE - 0.2V) ≤ VCM ≤ (VCC + 0.2V),

CMRR

0.2

3

mV/V

TAMB = +25ºC

TAMB = +25ºC,

220

500

650

200

300

500

650

200

300

1

AS1976 only VCC = 5.5V, ISINK = 8mA

TAMB = TMIN to TMAX,

AS1976 only VCC = 5.5V, ISINK = 8mA

Output Voltage Swing

High

VCC - VOH

mV

TAMB = +25ºC

AS1976 only VCC = 1.8V, ISOURCE = 1mA

80

220

70

TAMB = TMIN to TMAX,

AS1976 only VCC = 1.8V, ISOURCE = 1mA

TAMB = +25ºC,

AS1976 only VCC = 5.5V, ISINK = 8mA

TAMB = TMIN to TMAX,

AS1976 only VCC = 5.5V, ISINK = 8mA

Output Voltage Swing

Low

VOL

mV

TAMB = +25ºC,

VCC = 1.8V, ISOURCE = 1mA

TAMB = TMIN to TMAX,

VCC = 1.8V, ISOURCE = 1mA

Output Leakage

Current

ILEAK

ISC

AS1977 only, VOUT = 5.5V

0.001

µA

Sourcing, VOUT = VEE, VCC = 5.5V

Sourcing, VOUT = VEE, VCC = 1.8V

Sinking, VOUT = VCC, VCC = 5.5V

Sinking, VOUT = VCC, VCC = 1.8V

VCC = 1.8V

50

6

Output Short-Circuit

Current

mA

70

5

10

12

High-to-Low

tPD-

µs

Propagation Delay ⁴

VCC = 5.5V

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AS1976/AS1977

Data Sheet - Electrical Characteristics

Table 4. AS1976/AS1977 Electrical Characteristics (Continued)

Symbol

Parameter

Conditions

AS1976 only, VCC = 1.8V

Min

Typ

13

Max Units

AS1976 only, VCC = 5.5V

15

Low-to-High

tPD+

µs

Propagation Delay ⁴

AS1977 only, VCC = 1.8V, RPULUP = 100kΩ

AS1977 only, VCC = 3.6V, RPULUP = 100kΩ

AS1976 only, CLOAD = 15pF

CLOAD = 15pF

16

18

tRISE

tFALL

tON

Rise Time

Fall Time

10

ns

10

Power-Up Time

100

1. VOS is defined as the center of the hysteresis band at the input.

2. The hysteresis-related trip points are defined as the edges of the hysteresis band, measured with respect to the

center of the band (i.e., VOS) (see Figure 26 on page 11).

3. Guaranteed by design.

4. Specified with an input overdrive voltage (VOVERDRIVE) = 100mV, and load capacitance (CLOAD) = 15pF. VOVER-

DRIVE is defined above and beyond the offset voltage and hysteresis of the comparator input. A reference volt-

age error should also be added.

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AS1976/AS1977

Data Sheet - Typical Operating Characteristics

7 Typical Operating Characteristics

Figure 3. ICC vs. VCC and Temperature

Figure 4. ICC vs. Temperature

500

300

275

250

225

200

175

150

VCC = 3V

400

300

+85ºC

+25ºC

VCC = 5V

VCC = 1.8V

200

-40ºC

100

0

1.5

2.5

3.5

4.5

5.5

-40

-15

10

35

60

85

Supply Voltage (V)

Temperature (°C)

Figure 5. ICC vs. Output Transition Frequency

Figure 6. VOL vs. ISINK

50

600

500

400

40

VCC = 3V

VCC = 5V

30

VCC = 1.8V

VCC = 5V

300

200

100

0

20

VCC = 3V

VCC = 1.8V

10

0

1

10

100

1000 10000 100000

2

4

6

8

10

12

14

16

Output Transition Frequency (Hz)

Sink Current (mA)

Figure 7. VOL vs. ISINK and Temperature

Figure 8. VOH vs. ISOURCE

600

500

0.8

0.6

VCC = 1.8V

+25ºC

VCC = 3V

400

300

200

100

0

+85ºC

0.4

0.2

0

VCC = 5V

-40ºC

2

4

6

8

10

12

14

16

0

5

10

15

20

Sink Current (mA)

Source Current (mA)

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AS1976/AS1977

Data Sheet - Typical Operating Characteristics

Figure 9. VOH vs. ISOURCE and Temperature

Figure 10. Short Circuit Sink Current vs. Temperature

0.8

100

0.6

75

VCC = 5V

+25ºC

+85ºC

0.4

50

-40ºC

VCC = 3V

0.2

0

25

VCC = 1.8V

0

5

10

15

20

-40

-15

10

35

60

85

Source Current (mA)

Temperature (°C)

Figure 11. Short Circuit Source Current vs. Temperature Figure 12. tPD+ vs. Temperature

25

20

15

10

5

80

60

40

20

0

VCC = 5V

VCC = 1.8V

VCC = 3V

VCC = 1.8V

0

-40

-15

10

35

60

85

-40

-15

10

35

60

85

Temperature (°C)

Figure 13. tPD- vs. Temperature

Figure 14. tPD- vs. Capacitive Load

150

125

100

75

20

16

VCC = 5V

VCC = 3V

12

VCC = 1.8V

8

4

0

VCC = 1.8V

50

25

0

VCC = 3V

VCC = 5V

-40

-15

10

35

60

85

0.01

0.1

1

10

100

1000

Temperature (°C)

Capacitive Load (nF)

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AS1976/AS1977

Data Sheet - Typical Operating Characteristics

Figure 15. tPD+ vs. Capacitive Load

Figure 16. tPD+ 5V

200

150

100

VCC = 1.8V

50

VCC = 3V

VCC = 5V

0

0.01

0.1

1

10

100

1000

4µs/Div

Capacitive Load (nF)

Figure 17. tPD- 5V

Figure 18. tPD+ 3V

4µs/Div

Figure 19. tPD- 3V

Figure 20. tPD+ 1.8V

4µs/Div

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AS1976/AS1977

Data Sheet - Typical Operating Characteristics

Figure 21. tPD- 1.8V

Figure 22. 10kHz Response @ 1.8V

4µs/Div

20µs/Div

Figure 23. 1kHz Response @ 5V

Figure 24. Powerup/Powerdown Response

200µs/Div

40µs/Div

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AS1976/AS1977

Data Sheet - Detailed Description

8 Detailed Description

The AS1976/AS1977 are ultra low-current comparators and are guaranteed to operate with voltages as low as +1.8V.

The common-mode input voltage range extends 200mV beyond the rail voltages, and internal hysteresis ensures

clean output switching, even with slow input signals.

The AS1976 push/pull output stage sinks and sources-current. The AS1977 open-drain output stage can be pulled

beyond VCC to an absolute maximum of 3.6V > VEE. The AS1979/AS1977 are perfect for implementing wired-OR out-

put logic functions.

For all comparators, large internal output drivers allow rail-to-rail output swings with loads of up to 8mA. The output

stage design minimizes supply-current surges during switching, eliminating most power supply transients.

Input Stage

The input common-mode voltage range extends from (VEE - 0.2V) to (VCC + 0.2V), and the comparators can operate at

any differential input voltage within this range. The comparators have very low input bias current (±0.15nA, typ) if the

input voltage is within the common-mode voltage range.

Inputs are protected from over-voltage conditions by internal ESD protection diodes connected to the supply rails. As

the input voltage exceeds the supply rails, these ESD protection diodes are forward biased and begin to conduct.

Output Stage

The break-before-make output stage is capable of rail-to-rail operation with loads up to 8mA. Many comparators con-

sume orders of magnitude more current during switching than during steady-state operation.

Even at loads of up to 8mA, changes in supply-current during an output transition are extremely small (see Figure 5 on

page 6). As shown in Figure 5, the minimal supply current increases as the output switching frequency approaches

1kHz. This characteristic reduces the need for power-supply filter capacitors to reduce transients created by compara-

tor switching currents.

Because of the unique design of its output stage, the AS1976/AS1977 can dramatically increase battery life, even in

high-speed applications.

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AS1976/AS1977

Data Sheet - Application Information

9 Application Information

The AS1976/AS1977 comparators are perfect for use with all 2-cell battery-powered applications. Figure 25 shows a

typical application for the AS1977.

Figure 25. AS1977 Typical Application Circuit

VIN

5

4

VCC

IN-

RPULLUP

AS1977

1

OUT

3

2

IN+

VEE

Internal Hysteresis

The comparators were designed with 3mV of internal hysteresis to neutralize the effects of parasitic feedback, i.e., to

prevent unwanted rapid changes between the two output states.

The internal hysteresis in the AS1976/AS1977 creates two trip points:

ꢀ

Rising Input Voltage (VTHR) – The comparator switches its output from low to high as VIN rises above this trip point.

Falling Input Voltage (VTHF) – The comparator switches its output from high to low as VIN falls below this trip point.

ꢀ

The area between the trip points is the hysteresis band (VHB) (see Figure 26). When the AS1976/AS1977 input volt-

ages are equivalent, the hysteresis effectively causes one input to move quickly past the other, thus taking the input

out of the region where oscillation occurs. In Figure 26 IN- has a fixed voltage applied and IN+ is varied.

Note: If the inputs are reversed the output will be inverted.

Figure 26. Threshold Hysteresis Band

Thresholds

IN+

VTHR

Hysteresis

Band

IN-

VHB

VTHF

OUT

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AS1976/AS1977

Data Sheet - Application Information

Additional Hysteresis (AS1976)

Additional hysteresis can be added to the AS1976 and AS1978 with three resistors and positive feedback (see Figure

27), however, this positive feedback method slows hysteresis response time.

Figure 27. AS1976 Additional Hysteresis

VCC

R3

R1

VIN

+

–

VCC

VEE

OUT

R2

VREF

Resistor Selection Example

For the circuit shown in Figure 27, use the following steps to calculate values for R1, R2, and R3.

1. First select the value for R3. Leakage current at IN is less than 2nA, thus the current through R3 should be at least

0.2µA to minimize errors due to leakage current. The current through R3 at the trip point is:

(VREF - VOUT)/R3

(EQ 1)

Taking into consideration the two possible output states, solving for R3 yields two formulas:

R3 = VREF/IR3

(EQ 2)

(EQ 3)

R3 = (VCC - VREF)/IR3

Use the smaller of the two resulting values for R3. For example, for VREF = 1.245V, VCC = 3.3V, and IR3 = 1µA, the

two resistor values are 1.2MΩ and 2.0MΩ, therefore choose a 1.2MΩ standard resistor for R3.

2. Choose the required hysteresis band (VHB). For this example, choose 33mV.

3. Calculate R1 as:

R1 = R3(VHB/VCC)

Substituting the R1 and VHB example values gives:

(EQ 4)

(EQ 5)

R1 = 1.2MΩ(50mV/3.3V) = 12kΩ

4. Choose the trip point for VIN rising (VTHR) such that VTHR > VREF(R1 + R3)/R3. For this example, choose 3V.

5. Calculate R2 as:

R2 = 1/[VTHR/(VREF x R1) - (1/R1) - (1/R3)]

Substituting the R1 and R3 example values gives:

R2 = 1/[3.0V/(1.2V x 12kΩ) - (1/12kΩ) - (1/1.2MΩ)] = 8.05kΩ

In this example, a standard 8.2kΩ resistor should be used for R2.

6. Verify the trip voltages and hysteresis as:

VTHR = VREF x R1[(1/R1) + (1/R2) + (1/R3)]

VTHF = VTHR - (R1 x VCC/R3)

(EQ 6)

(EQ 7)

(EQ 8)

Hysteresis = VTHR - VTHF

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AS1976/AS1977

Data Sheet - Application Information

Additional Hysteresis (AS1977)

Additional hysteresis can be added to the AS1977 and AS1979 with 4 resistors and positive feedback (see Figure 28).

Figure 28. AS1977 Additional Hysteresis

VCC

R3

R4

R1

VIN

+

–

VCC

VEE

OUT

R2

VREF

Resistor Selection Example

For the circuit shown in Figure 28, use the following steps to calculate values for R1, R2, R3, and R4.

1. Select R3 according to one of these formulas:

R3 = VREF/1µA

R3 = (VCC - VREF)/1µA - R4

(EQ 9)

(EQ 10)

Use the smaller of the two resulting resistor values for R3.

2. Choose the hysteresis band required (VHB).

3. Calculate R1 as:

R1 = (R3 + R4)(VHB/VCC)

4. Choose the trip point for VIN rising (VTHR).

5. Calculate R2 as:

(EQ 11)

(EQ 12)

R2 = 1/[VTHR/(VREF x R1) - (1/R1) - 1/R3]

6. Verify the trip voltages and hysteresis as:

VIN rising: VTHR = VREF[R1(1/R1 + 1/R2 + 1/R3)]

VIN falling: VTHF = VREF[R1(1/R1 + 1/R2 + 1/(R3+R4))] - [1/(R3+R4)]VCC

Hysteresis = VTHR - VTHF

(EQ 13)

(EQ 14)

(EQ 15)

Zero-Crossing Detector

Figure 29 shows the AS1976 in a zero-crossing detector circuit. The inverting input (IN-) is connected to ground, and

the non-inverting input (IN+) is connected to a 100mVp-p signal source. When the signal at IN- crosses 0V, the signal

at OUT changes states.

Figure 29. Zero Crossing Detector

100mVp-p

3

+

1

IN+

4

OUT

–

IN-

AS1976

5

2

VCC

VEE

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AS1976/AS1977

Data Sheet - Application Information

Logic-Level Translation

The AS1977 can be used as a 5V-to-3V logic translator. Figure 30 shows an application that converts 5V- to 3V-logic

levels, and provides the full 5V logic-swing without creating overvoltage on the 3V logic inputs.

Note: When the comparator is powered by a 5V supply, RPULUP for the open-drain output should be connected to the

+3V supply voltage.

For 3V-to-5V logic-level translations, connect the +3V supply voltage to VCC and the +5V supply voltage to RPULUP.

Figure 30. AS1977 Logic-Level Translation Circuit

+3/+5V

5

VCC

+3/+5V

RPullup

100kΩ

4

1

+5/+3V

Logic Out

REF

OUT

AS1977

+5/+3V

Logic In

3

2

IN+

VEE

Logic-Level Translator

Layout Considerations

The AS1976/AS1977 requires proper layout and design techniques for optimum performance.

ꢀ

Power-supply bypass capacitors are not typically required, although 100nF bypass capacitors should be placed

close to the AS1976/AS1977 supply pins when supply impedance is high, leads are long, or for excessive noise on

the supply lines.

ꢀ

Minimize signal trace lengths to reduce stray capacitance.

A ground plane should be used.

Surface-mount components should be used whenever practical.

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AS1976/AS1977

Data Sheet - Package Drawings and Markings

10 Package Drawings and Markings

The AS1976/AS1977 are available in a 5-pin SOT23 package.

Figure 31. 5-pin SOT23 Package

Symbol

Min

0.90

0.00

0.90

0.30

0.09

2.80

2.60

1.50

0.30

Max

1.45

0.15

1.30

0.50

0.20

3.05

3.00

1.75

0.55

A

A1

A2

b

C

D

E

E1

L

e

0.95 REF

1.90 REF

e1

α

0º

8º

Notes:

1. Controlling dimension is millimeters.

2. Foot length measured at intercept point between datum A and lead surface.

3. Package outline exclusive of mold flash and metal burr.

4. Package outline inclusive of solder plating.

5. Meets JEDEC MO178.

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AS1976/AS1977

Data Sheet - Ordering Information

11 Ordering Information

The devices are available as the standard products shown in Table 5.

Table 5. Ordering Information

Type

Marking

ASI9

Description

Output Type Delivery Form

Package

AS1976

AS1976-T

AS1977

AS1977-T

Ultra-Low Current 1.8V Comparator

Push/Pull

Tube

5-pin SOT23

ASI9

Tape and Reel 5-pin SOT23

Tube 5-pin SOT23

ASJA

Open-Drain

Open-Drain Tape and Reel 5-pin SOT23

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AS1976/AS1977

Data Sheet

Copyrights

lated, stored, or used without the prior written consent of the copyright owner.

All products and companies mentioned are trademarks or registered trademarks of their respective companies.

Disclaimer

Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing

in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding

the information set forth herein or regarding the freedom of the described devices from patent infringement. austriami-

crosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior

to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information.

This product is intended for use in normal commercial applications. Applications requiring extended temperature

range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-

sustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for

each application. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard

production flow, such as test flow or test location.

The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However,

austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not limited to

personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or

consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the tech-

nical data herein. No obligation or liability to recipient or any third party shall arise or flow out of

austriamicrosystems AG rendering of technical or other services.

Contact Information

Headquarters

austriamicrosystems AG

A-8141 Schloss Premstaetten, Austria

Tel: +43 (0) 3136 500 0

Fax: +43 (0) 3136 525 01

For Sales Offices, Distributors and Representatives, please visit:

http://www.austriamicrosystems.com/contact

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型号：	AS1977
厂家：	AMS(艾迈斯)
描述：	Ultra-Low Current, 1.8V Comparators 超低电流， 1.8V比较放大器光电二极管
文件：	总17页 (文件大小：423K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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