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| UM2002 Datasheet, PDF (9/12 Pages) Union Semiconductor, Inc. – Bidirectional voltage level translator for open-drain and push-pull applications | |||
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UM2002
Application operating conditions
Refer to Figure 4
Symbol
Parameter
Conditions
Vref(B)
VI(EN)
Vref(A)
Isw(pass)
Iref
Reference Bias Voltage (B)
Input Voltage on pin EN
Reference Voltage (A)
Pass Switch Current
Reference Current
Transistor
Operating
Tamb Ambient Temperature
in
free-air
Note 8: All typical values are at Tamb = 25 °C.
Min
Vref(A) + 0.6
Vref(A) + 0.6
0
-40
Typ
(Note 8)
2.1
2.1
1.5
14
5
Sizing pull-up resistor
Max
5
5
4.4
+85
Unit
V
V
V
mA
μA
°C
The pull-up resistor value needs to limit the current through the pass transistor when it is in the
ON state to about 15mA. This ensures a pass voltage of 260mV to 350mV. If the current through
the pass transistor is higher than 15mA, the pass voltage also is higher in the ON state. To set the
current through each pass transistor at 15mA, the pull-up resistor value is calculated as:
RPU
ï½ Vpu(D) ï 0.35V
0.015 A
The table below summarizes resistor reference voltages and currents at 15mA, 10mA, and 3mA.
The resistor values shown in the +10 % column or a larger value should be used to ensure that the
pass voltage of the transistor would be 350 mV or less. The external driver must be able to sink
the total current from the resistors on both sides of the UM2002 device at 0.175V, although the
15mA only applies to current flowing through the UM2002 device.
Pull-up resistor values
Calculated for VOL = 0.35V; assumes output driver VOL = 0.175V at stated current.
Pull-up resistor value (Ω)
Vpu(D)
15mA
Nominal
+10 %
(Note 9)
10mA
Nominal
+10 %
(Note 9)
3mA
Nominal
+10 %
(Note 9)
5V
310
341
465
512
1550
1705
3.3V
197
217
295
325
983
1082
2.5V
143
158
215
237
717
788
1.8V
97
106
145
160
483
532
1.5V
77
85
115
127
383
422
1.2V
57
63
85
94
283
312
Note 9: +10 % to compensate for VCC range and resistor tolerance.
________________________________________________________________________
http://www.union-ic.com Rev.04 Feb.2014
9/12
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