nvt2003 NXP Semiconductors, nvt2003 Datasheet - Page 9

• Manufacturer Part Number: nvt2003
• Description: Bidirectional Voltage-level Translator For Open-drain And Push-pull Applications
• Manufacturer: NXP Semiconductors

NXP Semiconductors
NVT2003_04_06
Product data sheet
Fig 11. Bidirectional level shifting between two different power domains
The applied enable voltage V
than V
ref(A)
7.3 Bidirectional level shifting between two different power domains
7.4 Sizing pull-up resistor
MASTER
and V
I
2
C-BUS
GND
V
CC
nominally at the same potential
The less obvious application for the NVT2003 is for level shifting between two different
power domains that are nominally at the same potential, such as a 3.3 V system where
the line crosses power supply domains that under normal operation would be at 3.3 V, but
one could be at 3.0 V and the other at 3.6 V, or one could be experiencing a power failure
while the other domain is trying to operate. One of the NVT2003 three channel transistors
is used as a second reference transistor with its B side connected to a voltage supply that
is at least 1 V (and preferably 1.5 V) above the maximum possible for either V
V
channels are biased such that they turn OFF at the lower pull-up voltage, and if the two
pull-up voltages are equal, the channel is biased such that it just turns OFF at the
common pull-up voltage.
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 ensures a pass voltage of 260 mV to 350 mV. If the
current through the pass transistor is higher than 15 mA, the pass voltage also is higher in
the ON state. To set the current through each pass transistor at 15 mA, the pull-up resistor
value is calculated as:
Table 5
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
R
ref(B)
SDA
SCL
pu(B)
PU
for best translator operation.
=
V
. Then if either pull-up voltage is at 0 V, the channels are disabled, and otherwise the
pu(A)
V
------------------------------------- -
summarizes resistor reference voltages and currents at 15 mA, 10 mA, and 3 mA.
R PU
pu D
= 3.3 V
pu(H)
 
0.015 A
R PU
and the applied voltage at V
–
All information provided in this document is subject to legal disclaimers.
0.35 V
V
VREFA
pu(B)
A1
A2
A3
Rev. 2 — 29 March 2011
2
3
4
5
V
NVT2003
pu(H)
SW
SW
SW
1
GND
ref(A)
10 EN
9
8
7
6
and V
VREFB
B1
B2
B3
ref(B)
200 kΩ
should be such that V
Bidirectional voltage-level translator
V
pu(B)
R PU
= 3.3 V
NVT2003/04/06
R PU
SCL
SDA
I
DEVICE
2
C-BUS
GND
002aae967
V
ref(H)
CC
is at least 1 V higher
© NXP B.V. 2011. All rights reserved.
pu(A)
or
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