1. General description
The PCA9519 is a 4-channel level translating I
2
C-bus/SMBus repeater that enables the
processor low voltage 2-wire serial bus to interface with standard I
2
C-bus or SMBus I/O.
While retaining all the operating modes and features of the I
2
C-bus system during the
level shifts, it also permits extension of the I
2
C-bus by providing bidirectional buffering for
both the data (SDA) and the clock (SCL) lines, thus enabling the I
2
C-bus or SMBus
maximum capacitance of 400 pF on the higher voltage side. The SDA and SCL pins are
over-voltage tolerant and are high-impedance when the PCA9519 is unpowered.
The port B drivers are compliant with SMBus I/O levels, while port A uses a current
sensing mechanism to detect the input or output LOW signal which prevents bus lock-up.
The port A uses a 1 mA current source for pull-up and a 200 pull-down driver. This
results in a LOW on port A accommodating smaller voltage swings. The output pull-down
on the port A internal buffer LOW is set for approximately 0.2 V, while the input threshold
of the internal buffer is set about 50 mV lower than that of the output voltage LOW. When
the port A I/O is driven LOW internally, the LOW is not recognized as a LOW by the input.
This prevents a lock-up condition from occurring. The output pull-down on the port B
drives a hard LOW and the input level is set at 0.3 of SMBus or I
2
C-bus voltage level
which enables port B to connect to any other I
2
C-bus device or buffer.
The PCA9519 drivers are not enabled unless V
CC(A)
is above 0.8 V and V
CC(B)
is above
2.5 V. The enable (EN) pin can also be used to turn the drivers on and off under system
control. Caution should be observed to only change the state of the EN pin when the bus
is idle.
2. Features and benefits
4-channel (4 SCL/SDA pairs), bidirectional buffer isolates capacitance and allows
400 pF on port B of the device
Voltage level translation from port A (1 V to V
CC(B)
1.5 V) to port B (3.0 V to 5.5 V)
Requires no external pull-up resistors on lower voltage port A
Active HIGH repeater enable input
Open-drain inputs/outputs
Lock-up free operation
Supports arbitration and clock stretching across the repeater
Accommodates Standard-mode and Fast-mode I
2
C-bus devices and multiple masters
Powered-off high-impedance I
2
C-bus pins
Operating supply voltage range of 1.0 V to V
CC(B)
1.5 V on port A, 3.0 V to 5.5 V on
port B
5 V tolerant B-side SCL and SDA and enable pins
50 ns glitch filter on B-side input
PCA9519
4-channel level translating I
2
C-bus/SMBus repeater
Rev. 3 — 10 January 2013 Product data sheet
