NVT2001_NVT2002

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© NXP B.V. 2011. All rights reserved.

Product data sheet

Rev. 2 — 26 October 2011

7 of 23

NXP Semiconductors

NVT2001; NVT2002

Bidirectional voltage level translator

7.2 Bidirectional translation

For the bidirectional clamping configuration (higher voltage to lower voltage or lower

voltage to higher voltage), the EN input must be connected to VREFB and both pins pulled

regulate the EN input. A filter capacitor on VREFB is recommended. The master output

driver can be totem pole or open-drain (pull-up resistors may be required) and the slave

device output can be totem pole or open-drain (pull-up resistors are required to pull the Bn

the outputs must be 3-stateable and be controlled by some direction-control mechanism

to prevent HIGH-to-LOW contentions in either direction. If both outputs are open-drain, no

direction control is needed.

voltage. When VREFB is connected through a 200 k

 resistor to a 3.3 V to 5.5 V V

pu(D)

has a maximum output voltage equal to VREFA, and the output of each Bn has a

7.3 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 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 summarizes resistor reference voltages and currents at 15 mA, 10 mA, and 3 mA.

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 NVT20xx

device at 0.175 V, although the 15 mA only applies to current flowing through the

NVT20xx device.

[1]

R

PU

V

pu D



0.35 V

–

0.015 A

--------------------------------------

=

Table 5.

Pull-up resistor values

Pull-up resistor value (

)

64 mA

32 mA

15 mA

10 mA

3mA

Nominal

+10 %[1]

Nominal

+10 %[1]

Nominal

+10 %[1]

Nominal

+10 %[1]

Nominal

+10 %[1]

5 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