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Renesas 843252AGLF
- Part No.:
- 843252AGLF
- Manufacturer:
- Renesas
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
843252AGLF.pdf
- Description:
- IC FREQ SYNTH 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,026
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Product details
Overview
843252AGLF from Integrated Device Technology (IDT) is a dual-bank 3.3V LVPECL frequency synthesizer generating Ethernet reference clocks (125–625MHz) from a 25MHz crystal. It features two independent differential output banks, 0.36ps typical RMS phase jitter at 625MHz, and operates across 0°C to 70°C in a 16-pin TSSOP package for 10GbE/1GbE timing applications.
For engineers reviewing the 843252AGLF datasheet, 843252AGLF pinout, 843252AGLF application, or 843252AGLF equivalent, this page delivers verified specifications, bank-specific frequency configuration logic, LVPECL termination guidance, jitter performance under JEDEC 65, and industrial-grade supply filtering requirements - all confirmed against IDT's official Revision B datasheet.
Technical Context
The 843252AGLF integrates a third-generation low-phase-noise VCO (490–680MHz), dual independent PLL feedback paths with selectable ÷25/÷32 dividers (via FB_SEL), and separate analog (VCCA), core (VCC), and output (VCCO_A/VCCO_B) supplies to isolate noise between synthesis and output stages. Each bank uses dedicated LVCMOS/LVTTL select pins (SELA[1:0], SELB[1:0]) to configure output division ratios.
It implements crystal oscillator interface circuitry optimized for 18pF parallel-resonant 25MHz crystals, with internal pullup/pulldown resistors (51kΩ) on control inputs and supports LVCMOS clock injection via AC-coupled XTAL_IN. Output skew is specified at ≤80ps for same-frequency outputs and ≤190ps for differing frequencies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Type | Dual independent LVPECL differential pairs (QA/nQA, QB/nQB) - requires 50Ω termination to VCCO_X – 2V for valid logic levels. |
| Frequency Range | 125MHz, 156.25MHz, 312.5MHz, 625MHz - selectable per bank using SELA/SELB pins and FB_SEL divider mode. |
| RMS Phase Jitter | 0.36ps (typical) at 625MHz (1.875MHz–20MHz offset) - meets 10GbE jitter mask requirements without external filtering. |
| Supply Voltages | VCC = VCCO_A = VCCO_B = 3.3V ±5%; VCCA = 3.3V; VEE = 0V - separate supplies enable noise isolation between PLL core and outputs. |
| Operating Temp | 0°C to 70°C ambient - validated for commercial Ethernet infrastructure; industrial grade available on request. |
| Package | 16-pin TSSOP (4.4mm × 5.0mm × 0.925mm, G suffix) - RoHS-compliant, lead-free, JEDEC MO-153 compliant outline. |
| Crystal Interface | Optimized for 25MHz, 18pF parallel-resonant crystal; supports LVCMOS single-ended input via AC coupling. |
Pinout & Package
16-pin TSSOP (G package), 4.4mm × 5.0mm body, 0.65mm pitch, JEDEC MO-153 compliant. Thermal resistance θJA = 92.4°C/W (no airflow, multilayer PCB).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| nQB, QB | Bank B LVPECL differential output | Driven by dedicated VCCO_B supply; requires 50Ω termination to VCCO_B – 2V for valid VOH/VOL. |
| VCCO_B | Bank B output power supply | Isolates switching noise from Bank B outputs; bypass with 0.01µF capacitor per pin. |
| SELB1, SELB0 | Bank B frequency select inputs | LVCMOS/LVTTL inputs with internal 51kΩ pullups; set ÷2, ÷4, ÷5, or ÷8 output division for Bank B. |
| VCCO_A | Bank A output power supply | Independent of VCCO_B; enables independent voltage control and noise isolation for QA/nQA outputs. |
| QA, nQA | Bank A LVPECL differential output | Driven by VCCO_A; identical termination requirements as QB/nQB; supports same frequency set as Bank B. |
| FB_SEL | Feedback divider select | LVTTL input with internal 51kΩ pulldown; LOW = ÷25, HIGH = ÷32 - determines VCO multiplication factor with crystal. |
| XTAL_IN, XTAL_OUT | Crystal oscillator interface | Designed for 18pF parallel-resonant crystal; XTAL_IN accepts AC-coupled LVCMOS clock; XTAL_OUT unused when driven externally. |
| VCCA | Analog supply | Powers PLL analog circuitry; requires 10µF + 10Ω + 0.01µF RC filter to suppress high-frequency noise. |
| VCC | Core digital supply | Powers digital logic (control pins, dividers); bypass with 0.01µF capacitor; separate from VCCA/VCCO rails. |
| VEE | Negative supply reference | Connected to ground (0V); establishes LVPECL common-mode level; not a negative voltage rail. |
| SELA0, SELA1 | Bank A frequency select inputs | LVCMOS/LVTTL with internal 51kΩ pullups; configure Bank A output division independently of Bank B. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent output banks | QA/nQA and QB/nQB can be configured to different frequencies simultaneously (e.g., 625MHz + 156.25MHz), enabling multi-rate Ethernet PHY clocking. |
| Ultra-low phase jitter | 0.36ps RMS (625MHz) and 0.47ps RMS (156.25MHz) over 1.875MHz–20MHz integration band - satisfies IEEE 802.3ae 10GbE jitter limits. |
| Crystal-optimized architecture | Validated with 25MHz, 18pF parallel-resonant crystals; includes recommended C1/C2 load caps (22pF each) for ±10ppm accuracy. |
| Noise-isolated power domains | Four dedicated supplies (VCC, VCCA, VCCO_A, VCCO_B) prevent coupling between PLL core, analog VCO, and LVPECL output drivers. |
| LVCMOS clock injection support | XTAL_IN accepts single-ended LVCMOS signals (10ns edge rate min) via AC coupling - enables use of system clock instead of crystal. |
Applications
| 10GbE Line Cards | Multi-Port 1GbE Switches |
|---|---|
Use Scenario: Generating synchronized 625MHz and 156.25MHz clocks for 10GBASE-R and SFI interfaces on line cards with multiple SerDes lanes. IC Role / Device Role / Timing Role: Primary Ethernet reference clock synthesizer providing low-jitter differential clocks to PHYs and MACs. Use Value: 0.36ps RMS jitter at 625MHz ensures compliance with IEEE 802.3ae random jitter budget, reducing bit error rates without external jitter cleaners. | Use Scenario: Supplying independent 125MHz clocks to four separate 1GbE PHYs on a compact switch ASIC board. IC Role / Device Role / Timing Role: Dual-output clock source eliminating need for two discrete synthesizers or fanout buffers. Use Value: Independent SELA/SELB control allows per-PHY frequency tuning and dynamic reconfiguration without hardware change. |
| Optical Transport Modules | Industrial Ethernet Gateways |
Use Scenario: Providing 312.5MHz and 156.25MHz clocks to CPRI/eCPRI fronthaul transceivers requiring strict phase alignment. IC Role / Device Role / Timing Role: Low-skew (<80ps) dual-frequency source supporting deterministic latency in packet-based fronthaul. Use Value: Matched propagation delay between banks enables precise inter-channel phase synchronization critical for MIMO antenna arrays. | Use Scenario: Delivering robust 125MHz/156.25MHz clocks in factory automation gateways operating in electrically noisy environments. IC Role / Device Role / Timing Role: Industrial-grade timing IC with 0°C–70°C operation and separate analog/digital supplies for EMI resilience. Use Value: VCCA RC filtering and isolated VCCO rails suppress conducted noise from adjacent motor drives or PLCs, maintaining jitter <0.5ps. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LVPECL frequency synthesizer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 843251AGLF | Single-output version (one LVPECL bank); identical VCO, jitter, and crystal interface; lacks SELB pins and QB/nQB outputs. | Suitable only for single-clock systems; cannot replace dual-bank functionality without redesign. | Select when only one frequency output is required and board space is constrained. |
| Si5332-B-GM | Programmable 4-output clock generator with I²C interface; wider frequency range (0.16–350MHz per output); higher integration but higher power (220mA vs. 145mA). | Requires firmware configuration; supports fractional-N synthesis and spread spectrum; not pin-compatible. | Choose for flexible multi-frequency generation where programmability outweighs fixed-function simplicity. |
Compared with 843252AGLF, the 843251AGLF reduces cost and footprint but eliminates independent dual-bank operation, while the Si5332-B-GM offers software-defined timing at the expense of increased design complexity and power - making 843252AGLF optimal for fixed, low-jitter, dual-output Ethernet clocking.
Availability
843252AGLF is available at Aetrix Electronics and suitable for 10GbE line cards, multi-port Ethernet switches, optical transport modules, and industrial gateways requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.
Supply support for 843252AGLF 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
Integrated Device Technology (IDT), now part of Renesas Electronics, is a fabless semiconductor company specializing in timing, memory interface, RF, and sensor solutions for communications, computing, and industrial markets.
The 843252AGLF belongs to IDT's FemtoClock® family of ultra-low-jitter crystal-to-LVPECL synthesizers, engineered specifically for Ethernet, optical transport, and high-speed serial interface timing where sub-0.5ps RMS jitter is mandatory.
FAQ
What crystal specifications are required for reliable operation of the 843252AGLF?
The 843252AGLF is characterized and optimized for a 25MHz, 18pF parallel-resonant fundamental-mode crystal with ESR ≤50Ω, shunt capacitance ≤7pF, and drive level ≤1mW. Using this crystal with recommended 22pF load capacitors (C1/C2) achieves ±10ppm frequency accuracy. Deviations require recalculating feedback dividers using IDT's frequency tables.
How does the FB_SEL pin affect the output frequencies of the 843252AGLF?
The FB_SEL pin selects the feedback divider ratio: LOW configures ÷25, HIGH configures ÷32. This changes the VCO multiplication factor and thus the achievable output frequencies. For example, with a 25MHz crystal, FB_SEL = LOW enables 625MHz (×25), while FB_SEL = HIGH enables 622.08MHz (×24.8832) - both values are explicitly listed in Tables 3A and 3B of the 843252AGLF datasheet.
Can the 843252AGLF generate different frequencies on QA/nQA and QB/nQB simultaneously?
Yes, the 843252AGLF supports fully independent frequency configuration: SELA[1:0] controls Bank A (QA/nQA), SELB[1:0] controls Bank B (QB/nQB), and FB_SEL applies globally. For instance, SELA[1:0]=11 and SELB[1:0]=00 with FB_SEL=0 yields 156.25MHz on QA/nQA and 312.5MHz on QB/nQB - confirmed in Tables 3A and 3B of the 843252AGLF datasheet.
What is the maximum allowable output skew between QA/nQA and QB/nQB on the 843252AGLF?
The 843252AGLF specifies output skew of ≤80ps when both banks operate at the same frequency and ≤190ps when operating at different frequencies, measured at differential cross-points under matched load conditions. This is guaranteed across 0°C–70°C and defined per JEDEC Standard 65, ensuring deterministic timing for multi-lane SerDes applications.
Does the 843252AGLF require external termination resistors for its LVPECL outputs?
Yes, the 843252AGLF LVPECL outputs (QA/nQA, QB/nQB) require external 50Ω termination to VCCO_X – 2V (e.g., 1.3V when VCCO = 3.3V) to establish valid VOH (≈2.4V) and VOL (≈1.6V) levels. Figures 4A and 4B in the 843252AGLF datasheet show recommended Y-termination and Thevenin configurations - floating outputs are invalid and cause signal integrity failure.
843252AGLF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- FemtoClock®
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Frequency Synthesizer
- PLL:
- Yes
- Input:
- Crystal
- Output:
- LVPECL
- Number of Circuits:
- 1
- Ratio - Input:Output:
- 1:2
- Differential - Input:Output:
- No/Yes
- Frequency - Max:
- 625MHz
- Divider/Multiplier:
- Yes/No
- Voltage - Supply:
- 3.135V ~ 3.465V
- Operating Temperature:
- 0°C ~ 70°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 16-TSSOP
843252AGLF FAQ
1.How can I place an order for 843252AGLF through Aetrix?
Please submit a Request for Quotation (RFQ) for 843252AGLF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for 843252AGLF reliable?
The price and inventory of 843252AGLF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 843252AGLF is usually 5 days.
3.What payment methods are accepted for 843252AGLF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 843252AGLF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 843252AGLF?
843252AGLF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 843252AGLF order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for 843252AGLF?
For technical support, including 843252AGLF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 843252AGLF requirements.
6.How does Aetrix verify that 843252AGLF is sourced from the original manufacturer or authorized distributors?
All 843252AGLF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 843252AGLF meets industry standards.
7.What is the process for return or replacement of 843252AGLF?
All 843252AGLF units undergo pre-shipment inspection (PSI). If there is an issue with 843252AGLF, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The 843252AGLF part is unused and in its original packaging.
Return procedure for 843252AGLF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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