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I2C/SPI to Dual UART Bridge Controller

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The PI7C9X1172 is a I²C-bus/SPI to a dual-channel high performance UART bridge controller. It offers data rates up to 33Mbps and guarantees low operating and sleeping current. 
The PI7C9X1172 also has up to 8 additional programmable general purpose I/O [GPIO] pins. The device comes in very small QFN32 and TSSOP28 packages, which makes it ideally
suitable for cost efficient, handheld, battery operated applications. 
These UARTs provide a bridge for protocol conversion from I²C -bus or SPI to and RS-232/RS-485 and are fully bidirectional.
The PI7C9X1172 supports SPI clock speeds up to 33 Mbps and IrDA SIR up to 1.152 Mbit/s. PI7C9X1172’s internal register set is backward-compatible with the widely used and widely popular 16C450 UART. 
The PI7C9X1172 also provides additional advanced features such as auto hardware and software flow control, automatic RS-485 support,support for fractional baud rates and software reset.
This allows the software to reset the UART at any moment, independent of the hardware reset signal.


  • Dual channel full-duplex UART
  • Support I²C-bus or SPI interface
  • 64 bytes FIFO (transmitter and receiver)
  • Fully compatible with industry standard 16C450, 16C550
  • and 16C2550
  • Baud Rates up to 16Mbit/s in 4X sampling clock rate
  • Programmable character formatting:
    - 5-bit, 6-bit, 7-bit or 8-bit character
    - Even, odd, or no parity
    - 1, 1.5, or 2 stop bits
  • Programmable Receive and Transmit FIFO trigger levels
  • Special character detection
  • Internal Loopback mode
  • Line break generation and detection Flow control
  • Support hardware flow control using RTS/CTS
  • Support software flow control with programmable Xon /Xoff characters
  • Programmable single or double Xon/Xoff characters
  • Interface control
  • Automatic RS-485 slave address detection
  • RS-485 driver direction control via RTS signal
  • RS-485 driver direction control inversion
  • Built-in IrDA encoder and decoder interface
  • Supports IrDA SIR with speeds up to 115.2 kbit/s (optional 1.152Mbps)
  • Up to eight user programmable GPIO pins
  • Software reset

  • Low standby current at 3.3 V
  • Wide operation voltage (1.8V, 2.5V or 3.3V)
  • Industrial temperature ranges -40 ˚C to 85 ˚C
  • Available in QFN32 and TSSOP28 packages
  • Crystal oscillator (up to 24MHz) or external clock
  • (up to 64MHz) input
  • I²C interface
  • Compliant with I²C-bus fast speed
  • Support slave mode only SPI interface
  • PI7C9X1172 supports 33 Mbit/s maximum SPI clock speed
  • Support SPI mode 0 (slave mode only)


  • Industrial computing
  • Automation
  • Factory process control
  • Mobile computing
  • Embedded applications
  • Battery operated devices
  • Networking

Product Specifications

Product Parameters

Ports 2 UART
Pins 28,32
Data Rate (kbps) 16Mbps
Bytes 64
Tx/Rx FIFO Ctrs Yes
Tx/Rx FIFO INT Trig Yes
Auto RTS/CTS Yes
Interface I2C/SPI
Ambient or Junction Temperature (°C) -40 to 85

Technical Documents

Recommended Soldering Techniques


Additional Technical Documents are available upon request:
Application information, Evaluation board, and Other technical documents

Request Documents
Orderable Part Number Status Package Environmental Compliance Packing Buy from Distributor /
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Request Samples
Qty. Carrier
PI7C9X1172BLEX Obsolete TSSOP-28 GREEN 3000 T&R
PI7C9X1172BZHEX Obsolete W-QFN5050-32 GREEN 2500 T&R
PI7C9X1172CLE Active TSSOP-28 GREEN 50 TUBE Contact Sales Request Sample
PI7C9X1172CLEX Active TSSOP-28 GREEN 3000 T&R Contact Sales Request Sample

Environmental Compliance Legend:
LFF: Pb-Free Finish and RoHS 5/6
TLFP: Totally Pb-Free Product and RoHS 6/6
LFGP: Pb-free Finish and Green Product, RoHS 5/6 and Halogen Free
TPGP: Totally Pb-Free and Green Product, RoHS 6/6 and Halogen Free
GREEN: Halogen-free and RoHS compliant
RoHS: RoHS compliant but NOT halogen-free

Product Change Notices (PCNs)

A PCN may only apply to specific orderable part numbers in this datasheet. Please refer to the corresponding PCN to see the exact orderable part number(s) affected.

PCN # Issue Date Implementation Date Subject
PCN-2520 2021-05-27 2021-08-27 Qualified Additional Bump Site and Assembly/Test (A/T) Sites
PCN-2364 2018-10-04 2019-04-04 Device End of Life (EOL)
PCN-2328 2018-04-12 2018-10-12 Device End of Life for tray packaging only