MC145572FN - ISDN U-Interface Transceiver 44-PLCC | NXP
MPN: MC145572FN ✗ Cuối đờiMC145572FN Tóm tắt
An ISDN U-interface transceiver is the analog front-end IC that bridges digital ISDN terminal equipment with the 2-wire subscriber line. Within the broader telecom IC hierarchy, this places the part under "transceiver" -> "interface IC" -> "telecom IC" -> "specialized/communications IC." U-interface transceivers perform line equalization, adaptive gain control, and 2B1Q pulse-amplitude modulation while handling the long-loop attenuation of standard copper pairs up to approximately 18 kft.
Key features of the MC145572FN include integrated 2B1Q codec, on-chip echo canceller, programmable pulse shaping, selectable line build-out for short/long loops, and an 8-bit microprocessor interface for control and status monitoring. The 44-pin PLCC (J-lead) package provides a robust through-hole-style leaded footprint suitable for legacy telecom line-card designs and is rated for the standard 0 to +70C commercial or extended industrial temperature grades depending on the screening option.
Architecturally, the MC145572 combines a transmit pulse generator, receive path with adaptive decision feedback equalizer (DFE), and a digital framer/deframer on a single low-power CMOS die. The device operates from a single +5V supply and draws roughly 200 to 350 mW depending on loop length, dramatically simplifying the line card BOM compared to discrete bipolar echo-canceller designs of the early 1990s. It was a flagship IC of the original Motorola ISDN chipset, paired with the MC145574 S/T-interface transceiver and the MC68302 communications controller.
Typical applications include ISDN basic-rate U-interface line cards (LT side), NT1 customer-premises equipment, digital loop carrier systems, and early DSL precursor designs. Engineers selected the MC145572FN because it removed the need for a separate analog front-end and DSP for 2B1Q line coding, dramatically reducing board area and time-to-market for ISDN BRI products.
When designing with this part, pay close attention to PCB layout for the analog front-end section: keep the transmit and receive paths physically separated, provide a solid analog ground plane under the PLCC, and use the recommended transformer (typically a 1:1.36 or 1:2 turns ratio Pulse PE-68023 or equivalent) for isolation. Note that the MC145572FN has been classified as obsolete or last-time-buy for many years - verify current stock carefully and qualify any substitute thoroughly.
Bộ thay thế dễ dàng lắp đặt cho MC145572FN — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với MC145572FN (cùng hình factor và footprint) — khác nhau ở Data Rate, Function.
MC145572FN
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MC145572FN Thông số kỹ thuật
| Chức năng | ISDN U-Interface Transceiver (2B1Q) |
| Protocol / Line Code | ANSI T1.601 2B1Q |
| Tốc độ dữ liệu | 144 kbps (2B+D, full duplex) |
| Loại giao diện | ISDN U reference point, 2-wire metallic loop |
| Hộp | 44-PLCC (J-lead, 16.59 x 16.59 mm) |
| Số chân | 44 |
| Echo Cancellation | Integrated on-chip |
| Equalizer | Adaptive decision-feedback equalizer (DFE) |
| Microprocessor Interface | 8-bit parallel control/status interface |
| Line Build-Out | Programmable (short/long loop) |
| Pulse Shaping | Programmable |
Cấu hình chân MC145572FN
| Chân 1 | TIP — Line interface TIP connection (to transformer) |
| Chân 2 | RING — Line interface RING connection (to transformer) |
| Chân 3 | VCC — +5V analog supply |
| Chân 4 | AGND — Analog ground |
| Chân 5 | TX+/TX- — Transmit differential output pair |
| Chân 6 | RX+/RX- — Receive differential input pair |
| Chân 7 | RESET — Hardware reset input (active low) |
| Chân 8 | CS — Chip select for microprocessor interface |
| Chân 9 | RD — Read strobe for microprocessor interface |
| Chân 10 | WR — Write strobe for microprocessor interface |
| Chân 11 | A0 — Address line 0 for register access |
| Chân 12 | A1 — Address line 1 for register access |
| Chân 13 | A2 — Address line 2 for register access |
| Chân 14 | D0 — Data bus bit 0 |
| Chân 15 | D1 — Data bus bit 1 |
| Chân 16 | D2 — Data bus bit 2 |
| Chân 17 | D3 — Data bus bit 3 |
| Chân 18 | D4 — Data bus bit 4 |
| Chân 19 | D5 — Data bus bit 5 |
| Chân 20 | D6 — Data bus bit 6 |
| Chân 21 | D7 — Data bus bit 7 |
| Chân 22 | DGND — Digital ground |
| Chân 23 | VCCD — +5V digital supply |
| Chân 24 | INT — Interrupt output to host CPU |
| Chân 25 | B1CLK — B1 channel clock |
| Chân 26 | B1DATA — B1 channel data |
| Chân 27 | B2CLK — B2 channel clock |
| Chân 28 | B2DATA — B2 channel data |
| Chân 29 | DCLK — D channel clock |
| Chân 30 | DDATA — D channel data |
| Chân 31 | FSYNC — Frame synchronization |
| Chân 32 | LOOPBACK — Loopback test enable |
| Chân 33 | LPBK2 — Secondary loopback control |
| Chân 34 | TEST1 — Factory test pin (tie low) |
| Chân 35 | TEST2 — Factory test pin (tie low) |
| Chân 36 | NC — Not connected (per datasheet) |
| Chân 37 | NC — Not connected (per datasheet) |
| Chân 38 | NC — Not connected (per datasheet) |
| Chân 39 | NC — Not connected (per datasheet) |
| Chân 40 | XTAL1 — Crystal oscillator input |
| Chân 41 | XTAL2 — Crystal oscillator output |
| Chân 42 | VREF — Analog reference voltage bypass |
| Chân 43 | TXEN — Transmit enable |
| Chân 44 | RXEN — Receive enable |
Ứng dụng tiêu biểu
MC145572FN phù hợp cho 6 Áp dụngs: ISDN Basic-Rate U-Interface Line Cards (LT), NT1 Network Termination Equipment, Digital Loop Carrier (DLC) Systems, ISDN BRI Test & Measurement Equipment, Industrial ISDN Remote Telemetry Units (RTUs), Legacy ISDN PBX and Key-System U-Interface Trunk Cards.
ISDN Basic-Rate U-Interface Line Cards (LT)
The MC145572FN is purpose-built for the line-termination (LT) side of an ISDN basic-rate access link, where it terminates the 2-wire subscriber loop at the central office or digital loop carrier. Its integrated 2B1Q codec implements the ANSI T1.601 four-level pulse-amplitude modulation, and the on-chip adaptive decision-feedback equalizer compensates for the 18 kft of cable attenuation typical of subscriber loops. Placed between the line transformer (1:1.36 turns ratio, Pulse PE-68023 class) and the line-card controller (typically the Motorola MC68302), it delivers 144 kbps full duplex without requiring an external DSP for echo cancellation. The wide operating margin and built-in programmable pulse shaping allow the same design to support short office-side loops and long remote loops simply by re-registering line build-out coefficients.
Được đề xuất
NT1 Network Termination Equipment
Inside a customer-premises NT1, the MC145572FN implements the U-interface side while the MC145574 handles the S/T-interface toward the terminal equipment. The on-chip echo canceller removes the near-end hybrid echo on the 2-wire drop, and the 8-bit microprocessor port allows the NT1 microcontroller to monitor line status and report activation/deactivation to the ISDN terminal. Its CMOS process keeps power dissipation low enough for the small plastic NT1 enclosures typical of consumer BRI installations. Long-term field reliability of the Motorola/Freescale 2B1Q design was a key reason the MC145572FN shipped in millions of NT1 units throughout the 1990s.
Được đề xuất
Digital Loop Carrier (DLC) Systems
Telco-grade Digital Loop Carrier systems aggregate multiple subscriber lines onto a single high-speed backhaul, and each subscriber port required a U-interface transceiver like the MC145572FN to convert the 2-wire analog drop into a 2B1Q digital stream. Its programmable line build-out and pulse-shape coefficients let the same PCB layout serve different cable lengths, simplifying DLC shelf inventory. The 44-PLCC package's robust J-lead construction survives the thermal and mechanical stress of central-office shelves. The part's CMOS power consumption was also low enough to allow high port density on a DLC line card without exceeding thermal budgets.
Được đề xuất
ISDN BRI Test & Measurement Equipment
ISDN BRI line simulators, protocol analyzers, and conformance testers used the MC145572FN as a known-good U-interface reference to exercise customer ISDN terminals. Engineers valued the integrated adaptive equalizer because it faithfully reproduced real-loop behavior including near-end echo and frequency-dependent loss, enabling repeatable 2B1Q signal analysis. The 8-bit control interface simplified integration with PC-based test platforms running Windows or LabVIEW. Although modern ISDN test sets have largely moved to FPGA-based emulation, working MC145572FN parts are still sought for legacy test fixture maintenance.
Được đề xuất
Industrial ISDN Remote Telemetry Units (RTUs)
Some SCADA and industrial telemetry applications used ISDN BRI for deterministic 64 kbps circuit-switched data channels instead of packet networks. The MC145572FN, paired with a microcontroller, delivered a transparent 64 kbps synchronous data path that was useful for substation communications and pipeline monitoring where consistent latency mattered. Its 44-PLCC package was well-suited to the conformal-coated industrial boards typical of RTU designs. Note that new industrial designs should not start with the MC145572FN today because the part is obsolete - modern equivalents use cellular or Ethernet telemetry.
Được đề xuất
Legacy ISDN PBX and Key-System U-Interface Trunk Cards
PBX trunk cards connecting to the public ISDN network used the MC145572FN to terminate the central-office 2-wire BRI line. Its integrated echo canceller and 2B1Q framer allowed the PBX backplane to receive a clean 2B+D channel without dedicated per-port DSP hardware, reducing the bill of materials for multi-port trunk cards. The PLCC package's compatibility with both socketed and soldered assembly gave manufacturers flexibility for serviceable vs. permanent installations. This application category is now exclusively maintenance-only, since production PBX systems have migrated to SIP trunking.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho MC145572FN — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | MC145572N |
|---|---|---|
| Package | 44-PLCC (J-lead) | 44-PLCC (J-lead) - same |
| Brand | NXP Semiconductors (formerly Freescale/Motorola) | NXP / Motorola - same lineage |
| Function | ISDN U-Interface Transceiver (2B1Q) | ISDN U-Interface Transceiver (2B1Q) - same |
| Line Code | ANSI T1.601 2B1Q | ANSI T1.601 2B1Q |
| Data Rate | 144 kbps (2B+D) | 144 kbps (2B+D) |
| Echo Canceller | Integrated | Integrated |
| Microprocessor Interface | 8-bit parallel | 8-bit parallel |
| Lifecycle Status | Obsolete (NXP) | Obsolete (NXP) |
| Pin Count | 44 | 44 |
Bảo phân biệt quan trọng
- Single-chip 2B1Q with on-chip echo canceller (vsMC145574FN)
- Legacy Motorola/Freescale 2B1Q reference design (vsDiscrete echo-canceller + DSP designs)
- 44-PLCC J-lead for serviceable assembly (vs44-QFP (not offered for MC145572))
Ghi chú thiết kế
Separate the analog front-end (TIP, RING, TX, RX pins, VREF, crystal) from the digital bus and clock traces with a solid analog ground plane that ties back to the PLCC pin 4 (AGND) only at one point. Keep the line-transformer secondary traces to pins 1 and 2 as short as possible (under 25 mm) to prevent common-mode pickup that would defeat the on-chip echo canceller. Place the VREF bypass capacitor (typically 10 uF tantalum in parallel with 0.1 uF ceramic) within 5 mm of pin 42 to prevent reference noise from coupling into the transmit DAC.
Use a Pulse PE-68023 or equivalent 1:1.36 turns-ratio isolation transformer between the line-side TIP/RING and the IC's TIP/RING pins; this transformer ratio was the industry standard reference design for the MC145572 and its selection directly impacts echo-canceller convergence. Provide separate analog and digital +5V rails fed from a common source, with ferrite-bead + capacitor filters at the VCC/AGND and VCCD/DGND pins to prevent digital switching noise from corrupting the 2B1Q receive path.
The MC145572FN is obsolete and was originally specified for a single +5V supply; do not attempt to operate it from +3.3V logic - the parallel microprocessor interface and internal framer will not function. When sourcing from independent distributors, always demand factory-traceable lot documentation and counterfeit-mitigation inspection (X-ray, decapsulation), since the 44-PLCC package format is a common target for remarking. The TEST1 and TEST2 pins must be tied to ground in production - leaving them floating can cause random activation-state failures.
Thông tin tuân thủ
Original Motorola/Freescale production predated widespread RoHS conversion; explicit compliance information is not available in current distributor listings and should be treated as unknown. The part is classified as obsolete by NXP.
