ISL8487(2003) 查看數據表（PDF） - Intersil

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产品描述 (功能)

比赛名单

ISL8487
(Rev.:2003)

1/8 Unit Load, 5V, Low Power, High Speed or Slew Rate Limited, RS-485/RS-422 Transceivers

Intersil 

ISL8487, ISL81483, ISL81487

Electrical Specifications Test Conditions: VCC = 4.5V to 5.5V; Unless Otherwise Specified. Typicals are at VCC = 5V, TA = 25oC,

(Note 2) (Continued)

PARAMETER

SYMBOL

TEST CONDITIONS

TEMP

(oC) MIN TYP MAX UNITS

Driver Enable from Shutdown to

Output High

tZH(SHDN) CL = 100pF, SW = GND, (Figure 3, Notes 7, 8) Full

-

1000 2000 ns

Driver Enable from Shutdown to

tZL(SHDN) CL = 100pF, SW = VCC, (Figure 3, Notes 7, 8)

Full

Output Low

-

1000 2000 ns

Receiver Enable from Shutdown to tZH(SHDN) CL = 15pF, SW = GND, (Figure 5, Notes 7, 9)

Full

-

800 2500 ns

Output High

Receiver Enable from Shutdown to tZL(SHDN) CL = 15pF, SW = VCC, (Figure 5, Notes 7, 9)

Full

-

800 2500 ns

Output Low

NOTES:

2. All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device ground unless

otherwise specified.

3. Supply current specification is valid for loaded drivers when DE = 0V.

4. Applies to peak current. See “Typical Performance Curves” for more information.

5. When testing the ISL8487 and ISL81483, keep RE = 0 to prevent the device from entering SHDN.

6. When testing the ISL8487 and ISL81483, the RE signal high time must be short enough (typically <200ns) to prevent the device from entering

SHDN.

7. The ISL8487 and ISL81483 are put into shutdown by bringing RE high and DE low. If the inputs are in this state for less than 50ns, the parts are

guaranteed not to enter shutdown. If the inputs are in this state for at least 600ns, the parts are guaranteed to have entered shutdown. See

“Low-Power Shutdown Mode” section.

8. Keep RE = VCC, and set the DE signal low time >600ns to ensure that the device enters SHDN.

9. Set the RE signal high time >600ns to ensure that the device enters SHDN.

10. Devices meeting these limits are denoted as “1/8 unit load (1/8 UL)” transceivers. The RS-485 standard allows up to 32 Unit Loads on the bus,

so there can be 256 1/8 UL devices on a bus.

11. Devices meeting these limits are denoted as “1/4 unit load (1/4 UL)” transceivers. The RS-485 standard allows up to 32 Unit Loads on the bus,

so there can be 128 1/4 UL devices on a bus.

Test Circuits and Waveforms

VCC DE

DI

Z

D

Y

VOD

R

R

VOC

FIGURE 1. DRIVER VOD AND VOC

6

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