6
FN6050.7
July 31, 2006
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
Output Low
tZL(SHDN) CL = 100pF, SW = VCC, (Figure 3, Notes 7, 8) Full
-
1000
2000
ns
Receiver Enable from Shutdown to
Output High
tZH(SHDN) CL = 15pF, SW = GND, (Figure 5, Notes 7, 9) Full
-
800
2500
ns
Receiver Enable from Shutdown to
Output Low
tZL(SHDN) CL = 15pF, SW = VCC, (Figure 5, Notes 7, 9) Full
-
800
2500
ns
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
FIGURE 1. DRIVER VOD AND VOC
Electrical Specifications
Test Conditions: VCC = 4.5V to 5.5V; Unless Otherwise Specified. Typicals are at VCC = 5V, TA = 25°C,
(Note 2) (Continued)
PARAMETER
SYMBOL
TEST CONDITIONS
TEMP
(°C)
MIN
TYP
MAX
UNITS
D
DE
DI
VCC
VOD
VOC
R
Z
Y
ISL8487, ISL81483, ISL81487