1. General description

The NCA9701A is a dual-channel bidirectional repeater for I²C and SMBus/PMBus applications.

It targets the Fast-mode Plus (Fm+) of the I²C protocol, making the true 1 MHz operation possible

without violating I²C timing specifications. This is achieved by using edge accelerators added at all

NCA9701A ports that speed up the LOW-to-HIGH transitions of I²C input and output signals.

The NCA9701A provides the buffering for both clock (SCL) and data (SDA) I²C signals with

the voltage level translation possibility (up and down) at the same time. The unique feature of

the IC is the same operating voltage range of 1.08 V to 3.6 V that can be applied at both port A

and port B of the device. This offers more flexibility in how the device can be used in the target

application. Multiple NCA9701As can be connected in series or in star, and their ports A and B can

be exchanged. Only when the I²C clock stretching needs to be supported, the NCA9701A port A

must be connected to the I²C Master side and the NCA9701A port B to the I²C Slave side.

The NCA9701A features integrated pull-up resistors of 4.3 kΩ at each I/O pin. This simplifies

the system implementation and reduces BOM count. Though external pull-up resistors are not

required, they might be added to shorten the rise times of I²C signals even further.

The NCA9701A provides true signal buffering as the device implementation does not use the

pass-FET topology. No static or incremental offsets are needed either, and the lock-free operation

is guaranteed by an innovative implementation of the buffers. The very low VOL levels on port A

and B improve the noise margin in the application and the potential noise components of input

signals are filtered out by Schmitt trigger inputs. To reduce EMI, the negative edges of output

signals are slew-controlled.

The NCA9701A is well suited for high-performance low-power applications which use the I²C

communication protocol.

2. Features and benefits

• Two-channel bidirectional I²C buffer

• Voltage level translation from 1.08 V to 3.6 V at both port A and port B with unconstrained

combination of the supply voltage levels

• Guaranteed 1 MHz operation (true I²C Fast-mode Plus, Fm+)

• Support for the I²C Standard-mode (Sm) and Fast-mode (Fm) operation

• No static voltage offset

• Very low VOL on I/O pins of the port A; VOL regulated to 0.1VCCB on I/O pins of the port B

• Input and output rising-edge signal accelerators at all I/Os

• Active-HIGH enable input referenced to VCCA supply

• Lock-free operation

• Glitch-free and sequence-independent IC power-up

• Open-drain input/outputs

• Series connection and star connection of NCA9701A devices possible

• I²C clock stretching support

• Compatibility with I²C bus and SMBus protocols

• Latch-up performance exceeds 100 mA per JESD 78B Class II

• ESD protection:

• HBM: ANSI/ESDA/JEDEC JS-001 class 2 exceeds 2 kV

• CDM: ANSI/ESDA/JEDEC JS-002 class C3 exceeds 1 kV

• Very small footprint

3. Applications

• Smart phones and tablets

• Portable medical devices

• Portable instrumentation and test equipment

• Devices for IoT applications

• Power-sensitive applications