GTL2003 Ver la hoja de datos (PDF) - NXP Semiconductors.
Número de pieza
componentes Descripción
Fabricante
GTL2003 Datasheet PDF : 24 Pages
| |||
NXP Semiconductors
GTL2003
8-bit bidirectional low voltage translator
8.4 Sizing pull-up resistor
The pull-up resistor value needs to limit the current through the pass transistor when it is
in the ‘on’ state to about 15 mA. This will guarantee a pass voltage of 260 mV to 350 mV.
If the current through the pass transistor is higher than 15 mA, the pass voltage will also
be higher in the ‘on’ state. To set the current through each pass transistor at 15 mA, the
pull-up resistor value is calculated as shown in Equation 1:
resistor value = -p---u---l--l------u---p-----v---o----l--t--a---g---e--------V-------–-------0---.-3---5-----V--
(1)
0.015 A
When using open-drain devices, it is always required to use pull-up resistors at D-side,
and they must be sized so as not to overload the output. If VDD1 VSREF < 1.5 V, then
pull-up resistor is required on S-side to pull up the Sn outputs to VSREF. It is important to
note that if pull-up resistors are required on both the S-side and D-side, the equivalent
pull-up resistor value becomes the parallel combination of the two resistors when pass
transistor is ON. If VDD1 VSREF 1.5 V, then pull-up resistors on the S-side are not
required.
Table 6 summarizes resistor values for various reference voltages and currents at 15 mA
and also at 10 mA and 3 mA for VDD1 VSREF 1.5 V. The resistor value 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 GTL-TVC device at 0.175 V, although the
15 mA only applies to current flowing through the GTL-TVC device. See application note
AN10145, “Bidirectional low voltage translators” (Ref. 2) for more information.
Table 6. Pull-up resistor values
Calculated for VOL = 0.35 V. Assumes output driver VOL = 0.175 V at stated current.
Pull-up resistor value ()
Voltage
15 mA
10 mA
3 mA
Nominal + 10 %[1] Nominal + 10 %[1] Nominal + 10 %[1]
5.0 V
310
341
465
512
1550
1705
3.3 V
197
217
295
325
983
1082
2.5 V
143
158
215
237
717
788
1.8 V
97
106
145
160
483
532
1.5 V
77
85
115
127
383
422
1.2 V
57
63
85
94
283
312
1.1 V
50
55
75
83
250
275
1.0 V
44
48
65
72
217
239
0.95 V
40
44
60
66
200
220
0.9 V
37
41
55
61
183
201
0.85 V
34
37
50
55
167
184
0.8 V
30
33
45
50
150
165
[1] + 10 % to compensate for VDD range and resistor tolerance.
GTL2003
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 2 — 3 July 2012
© NXP B.V. 2012. All rights reserved.
7 of 24
Share Link: 