NXP Semiconductors SC68C752BIB48,151

Overview

SC68C752BIB48,151 from NXP Semiconductors is a dual-channel UART IC with Motorola 68-mode parallel interface, 64-byte transmit/receive FIFOs, hardware/software flow control, and support for data rates up to 5 Mbit/s. It operates across 2.5 V, 3.3 V, and 5 V supply rails, features programmable baud rate generation, and targets embedded industrial communication systems requiring dual serial channel management with low CPU overhead.

For engineers reviewing the SC68C752BIB48,151 datasheet, SC68C752BIB48,151 pinout, SC68C752BIB48,151 application, or SC68C752BIB48,151 equivalent, key selection considerations include its LQFP48 package, dual-channel independent addressing via A3, auto-RTS/CTS trigger level programmability in TCR, RXRDY/TXRDY DMA signaling, and industrial temperature range (−40 °C to +85 °C).

Technical Context

The SC68C752BIB48,151 implements two independent UART channels sharing a single 8-bit Motorola-style parallel bus (D0–D7, R/W, A0–A3, CS), with channel selection controlled by A3. Each channel supports full modem control (RTS/CTS/DSR/DTR/RI/CD) and has dedicated status reporting via Line Status Register (LSR) and Modem Status Register (MSR).

Its FIFO architecture uses separate 64-byte receive and transmit buffers per channel, with programmable trigger levels (via TLR and TCR) for interrupt and DMA activation. Baud rate generation employs a prescaler plus 16-bit divisor, enabling precise timing from XTAL1/XTAL2 inputs up to 5 Mbit/s.

Key Specifications

Pinout & Package

LQFP48 package (SOT313-2), 7 × 7 × 1.4 mm body, 0.5 mm pitch, exposed pad not present. Pin 1 index located at top-left corner (see Fig 2 in datasheet).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual UART applications.

Compared with SC16C752BIB48,151, the SC68C752BIB48,151 delivers higher data rate headroom and richer flow control for protocol-aware firmware; versus TL16C752BPTR, it preserves 68-mode timing and A3-based channel selection-critical for drop-in replacement in legacy Motorola architectures.

Availability

SC68C752BIB48,151 is available at Aetrix Electronics and suitable for industrial automation, legacy system upgrades, and multi-protocol gateway designs requiring stable component supply, long-term lifecycle assurance, and guaranteed traceable sourcing.

Supply support for SC68C752BIB48,151 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in communication peripherals and mixed-signal design.

The SC68C752BIB48,151 belongs to NXP's legacy UART product line designed specifically for industrial control systems requiring robust dual-channel serial bridging with Motorola bus compatibility and extended temperature operation.

FAQ

What is the maximum data rate supported by the SC68C752BIB48,151?

The SC68C752BIB48,151 supports data rates up to 5 Mbit/s per channel, achieved via its programmable 16-bit baud rate divisor and prescaler circuit. This maximum rate assumes optimal clock input (e.g., 40 MHz XTAL) and proper signal integrity on TX/RX lines. The actual achievable rate depends on external crystal accuracy, PCB layout, and line driver/receiver characteristics - the SC68C752BIB48,151 itself imposes no lower-layer limitation beyond its internal timing specification.

Does the SC68C752BIB48,151 support both Intel and Motorola bus interfaces?

No, the SC68C752BIB48,151 implements only the Motorola 68-mode parallel interface, defined by R/W (not RD/WR), A0–A3 address lines, and CS control. It does not support Intel 80-style timing or signal polarity. Attempting to interface with an Intel bus without level/shaping logic will result in incorrect register access and undefined behavior - the SC68C752BIB48,151 requires strict adherence to 68k-compatible strobing and setup/hold timing.

How does hardware flow control work on the SC68C752BIB48,151?

Hardware flow control on the SC68C752BIB48,151 uses auto-RTS and auto-CTS functions enabled independently via EFR[6] and EFR[7]. Auto-RTS asserts RTSn when the receive FIFO level falls below the halt trigger (TCR[3:0]) and deasserts it upon reaching that level; auto-CTS gates transmission based on CTSn state. Both functions operate without CPU intervention - the SC68C752BIB48,151 handles all timing and state transitions internally, eliminating overrun errors during sustained high-speed transfers.

Can the SC68C752BIB48,151 operate from a 2.5 V supply while interfacing with 5 V logic inputs?

Yes, the SC68C752BIB48,151 supports 2.5 V, 3.3 V, and 5 V operation, and its RXA/RXB, CDA/CDB, DSRA/DSRB, RIA/RIB, and CTSA/CTSB inputs are explicitly 5 V tolerant per the datasheet. When powered at 2.5 V, these pins accept 0–5 V input signals without damage or level-shifting circuitry - the SC68C752BIB48,151 maintains full functionality and timing compliance across all three supply voltages.

What is the function of the TCR register in the SC68C752BIB48,151?

The Transmission Control Register (TCR) in the SC68C752BIB48,151 stores the receiver FIFO halt and resume trigger levels used exclusively by auto-RTS flow control - bits [3:0] set the halt level (RTSn deassertion), and bits [7:4] set the resume level (RTSn reassertion). Unlike the Trigger Level Register (TLR), which controls interrupt/DMA activation, the TCR values are referenced only during hardware flow control operation - the SC68C752BIB48,151 uses them to dynamically manage RTS signaling based on real-time FIFO occupancy.