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Home > Products > Integrated Circuits (ICs) > Clock/Timing > Clock Generators, PLLs, Frequency Synthesizers

Analog Devices Inc./Maxim Integrated DS21604N

Name: DS21604N
Brand: Analog Devices Inc./Maxim Integrated
SKU: DS21604N
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: DS21604N

Manufacturer:: Analog Devices Inc./Maxim Integrated

Category:: Clock Generators, PLLs, Frequency Synthesizers

Package:: 8-DIP (0.300", 7.62mm)

Datasheet:: DS21604N.pdf

Description:: IC CLOCK RATE ADAPTER 8DIP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

DS21604N from Maxim Integrated is a 3.3V/5V clock rate adapter IC designed for telecom timing conversion between T-carrier (1.544 MHz) and E-carrier (2.048 MHz / 4.096 MHz) systems. It provides two synchronized clock outputs - CLKOUT1 (1.544 MHz or 4.096 MHz) and CLKOUT2 (6.176 MHz or 8.192 MHz) - plus an 8 kHz frame-sync output, all frequency-locked to CLKIN. Used in TDM multiplexers and line interface units requiring precise carrier clock translation.

For engineers reviewing the DS21604N datasheet, DS21604N pinout, DS21604N application, or DS21604N equivalent, this page delivers verified technical context, industrial-grade timing specifications, frame-sync alignment behavior, jitter performance per G.823/TR62411, and drop-in compatibility with LXP604SE across SO and DIP packages.

Technical Context

The DS21604N implements a PLL-based analog frequency synthesizer with feedback divider and frame-sync generator, enabling bidirectional T/E-carrier clock conversion. Its SEL pin selects between high-to-low (4.096 MHz → 1.544 MHz) and low-to-high (1.544 MHz → 4.096 MHz / 8.192 MHz) modes, with all outputs phase-aligned to SYNCIN when asserted.

It supports 8 kHz frame synchronization with ≤50 ms lock time and operates with ±10,000 ppm capture/lock range on CLKIN. Output jitter meets G.823 (0.018–0.035 UI_P-P) and TR62411 (0.005–0.012 UI_P-P) standards depending on band and conversion direction.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	3.3V ±5% or 5V ±5% - dual-voltage operation enables legacy 5V and modern 3.3V system integration without level-shifting.
CLKIN Frequency Options	1.544 MHz or 4.096 MHz - supports T1 input and high-speed E1 variants, validated per Table 2-A for DS21604.
CLKOUT1 Output	1.544 MHz (SEL=1) or 4.096 MHz (SEL=0) - primary carrier clock output, duty cycle 50%, delay ±15 ns (3.3V).
CLKOUT2 Output	6.176 MHz (SEL=1) or 8.192 MHz (SEL=0) - higher-rate clock for oversampling or auxiliary timing, synchronized to CLKIN.
SYNCOUT Frequency	8 kHz - always active, frequency-locked to CLKIN, used for frame alignment in TDM systems.
Output Jitter (TR62411)	0.005–0.012 UI_P-P (10 Hz–40 kHz) - ensures compliance with telecom jitter masks for E1/T1 line interfaces.
Operating Temperature	−40°C to +85°C - industrial-grade thermal rating suitable for outdoor telecom cabinets and base station equipment.

Pinout & Package

DS21604N is supplied in an 8-pin plastic DIP package (P8+8), with pins arranged in dual in-line configuration for through-hole mounting and prototyping. Pin 1 is located at the left end of the top row when viewed from top with notch or dot orientation.

Pin/Terminal	Circuit Role	Design Meaning
1	SYNCOUT	8 kHz frame-synchronization output; aligned to CLKOUT2 rising edge (t_DF = −5 to +30 ns); used for TDM slot alignment.
2	CLKOUT2	High-rate clock output (6.176 MHz or 8.192 MHz); referenced to CLKIN; rise/fall time ≤75 ns (3.3V, 100 pF load).
3	CLKIN	Reference clock input (1.544 MHz or 4.096 MHz); accepts ±10,000 ppm variation; duty cycle 35–65%.
4	CLKOUT1	Primary carrier clock output (1.544 MHz or 4.096 MHz); 50% duty cycle; delay t_D = −15 to +41 ns (3.3V).
5	Vss	Ground reference for analog and digital circuitry; must be low-impedance connection to minimize jitter coupling.
6	SEL	Mode select input; logic high selects 4.096 MHz → 1.544 MHz conversion; logic low selects 1.544 MHz → 4.096/8.192 MHz.
7	SYNCIN	Frame-sync input (8 kHz or integer subrate); enables phase alignment of all outputs; tie high/low if unused.
8	VDD	Positive supply (3.3V or 5V); decoupling capacitor required near pin to suppress supply noise affecting jitter.

Key Features

Feature	Design Value
Direct LXP604SE replacement	Pin-compatible and functionally identical to LXP604SE, enabling drop-in upgrade in existing E1/T1 line cards without layout change.
Bidirectional carrier conversion	Supports both T→E (1.544 MHz ↔ 2.048 MHz) and E→T (4.096 MHz ↔ 1.544 MHz) paths, eliminating need for separate direction-specific parts.
No external components	Integrated PLL, dividers, and sync generator require zero external capacitors or resistors - reduces BOM count and board area.
Low-jitter frame-aligned outputs	Meets TR62411 mask down to 0.005 UI_P-P; SYNCOUT phase-aligned to CLKOUT2 enables deterministic TDM slot timing.
Industrial temperature support	Guaranteed operation from −40°C to +85°C with full AC/DC specs - qualified for uncontrolled telecom environments.

Applications

E1 Line Interface Unit	T1 Multiplexer Timing
Use Scenario: E1 framer in access node converting between local E1 clock domain and upstream T1 transport. IC Role / Device Role / Timing Role: Clock rate adapter generating 1.544 MHz T1 clock and 8 kHz frame sync from 2.048/4.096 MHz E1 input. Use Value: Enables interoperability between E1 and T1 networks using single DS21604N, avoiding dual-clock source complexity.	Use Scenario: T1 aggregation switch synchronizing multiple T1 lines to a common E1 backplane clock. IC Role / Device Role / Timing Role: Generates 4.096 MHz E1 clock and 8 kHz frame sync from incoming 1.544 MHz T1 reference. Use Value: Maintains bit-level alignment across aggregated T1 streams via phase-coherent CLKOUT1 and SYNCOUT outputs.
Legacy LXP604SE Upgrade Path	Multi-Rate Telecom Test Equipment
Use Scenario: Field upgrade of aging LXP604SE-based line cards to newer silicon with same footprint and timing behavior. IC Role / Device Role / Timing Role: Direct replacement providing identical pinout, mode selection, and jitter performance as LXP604SE. Use Value: Eliminates redesign effort while improving supply chain continuity and RoHS compliance (DS21604N+ variant available).	Use Scenario: Lab-grade signal generator supporting configurable T/E-carrier clock synthesis for protocol validation. IC Role / Device Role / Timing Role: Programmable clock source delivering selectable 1.544/2.048/4.096/6.176/8.192 MHz outputs with frame-sync trigger. Use Value: Single DS21604N covers five key telecom frequencies, reducing instrument channel count and calibration overhead.

E1 Line Interface Unit

T1 Multiplexer Timing

Use Scenario: E1 framer in access node converting between local E1 clock domain and upstream T1 transport.

IC Role / Device Role / Timing Role: Clock rate adapter generating 1.544 MHz T1 clock and 8 kHz frame sync from 2.048/4.096 MHz E1 input.

Use Value: Enables interoperability between E1 and T1 networks using single DS21604N, avoiding dual-clock source complexity.

Use Scenario: T1 aggregation switch synchronizing multiple T1 lines to a common E1 backplane clock.

IC Role / Device Role / Timing Role: Generates 4.096 MHz E1 clock and 8 kHz frame sync from incoming 1.544 MHz T1 reference.

Use Value: Maintains bit-level alignment across aggregated T1 streams via phase-coherent CLKOUT1 and SYNCOUT outputs.

Legacy LXP604SE Upgrade Path

Multi-Rate Telecom Test Equipment

Use Scenario: Field upgrade of aging LXP604SE-based line cards to newer silicon with same footprint and timing behavior.

IC Role / Device Role / Timing Role: Direct replacement providing identical pinout, mode selection, and jitter performance as LXP604SE.

Use Value: Eliminates redesign effort while improving supply chain continuity and RoHS compliance (DS21604N+ variant available).

Use Scenario: Lab-grade signal generator supporting configurable T/E-carrier clock synthesis for protocol validation.

IC Role / Device Role / Timing Role: Programmable clock source delivering selectable 1.544/2.048/4.096/6.176/8.192 MHz outputs with frame-sync trigger.

Use Value: Single DS21604N covers five key telecom frequencies, reducing instrument channel count and calibration overhead.

Equivalent & Alternatives

The following parts are listed as comparable options for similar clock rate adapter applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
LXP604SE	Same pinout, identical AC/DC specs, but obsolete and not RoHS-compliant; DS21604N offers lead-free option (N+).	Designed for same E1↔T1 conversion roles; no functional difference in timing behavior or frame-sync alignment.	Select DS21604N for new designs requiring RoHS compliance and long-term supply; LXP604SE only for legacy repair.
DS21604SN	Same die, 16-pin SO package instead of 8-pin DIP; identical electrical specs and timing performance.	SO package preferred for automated SMT assembly; DIP (DS21604N) used for prototyping, repair, or through-hole legacy systems.	Choose DS21604N for hand-soldering, field replacement, or breadboard evaluation; DS21604SN for volume production PCBs.

Compared with LXP604SE and DS21604SN, the DS21604N delivers identical timing functionality and jitter performance in a through-hole DIP package, enabling direct mechanical replacement in legacy systems while supporting modern 3.3V operation and RoHS compliance via the N+ variant.

Availability

DS21604N is available at Aetrix Electronics and suitable for E1/T1 line interface units, telecom multiplexers, legacy LXP604SE upgrades, and multi-rate test equipment requiring stable component supply across industrial temperature ranges.

Supply support for DS21604N 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

Maxim Integrated (now part of Analog Devices) is a U.S.-based semiconductor company specializing in precision analog, mixed-signal, and power management ICs for industrial, telecom, and computing markets.

The DS21604N belongs to Maxim's telecom timing adapter product line, engineered specifically for carrier-grade clock translation in TDM infrastructure where jitter, phase alignment, and interoperability between E1 and T1 standards are critical.

FAQ

What clock conversion modes does the DS21604N support?

The DS21604N supports two bidirectional modes controlled by the SEL pin: SEL = 0 configures 1.544 MHz → 4.096 MHz (CLKOUT1) and 8.192 MHz (CLKOUT2); SEL = 1 configures 4.096 MHz → 1.544 MHz and 6.176 MHz. Both modes deliver an always-active 8 kHz SYNCOUT locked to CLKIN.

Is the DS21604N pin-compatible with the LXP604SE?

Yes, the DS21604N is a direct pin-compatible and functionally identical replacement for the LXP604SE, including identical pin mapping, timing behavior, and electrical specifications. This allows drop-in substitution in existing designs without PCB modification.

What is the maximum jitter specification for DS21604N CLKOUT1 output?

The DS21604N CLKOUT1 output exhibits ≤0.012 UI_P-P (typical) jitter in the 10 Hz–40 kHz band per TR62411, and ≤0.035 UI_P-P (max) in the 20 Hz–100 kHz band per G.823 - verified for both 4.096 MHz → 1.544 MHz and 1.544 MHz → 4.096 MHz conversions.

Can DS21604N operate from a 3.3V supply?

Yes, the DS21604N is fully specified for 3.3V ±5% operation, with guaranteed DC and AC performance including supply current (14 mA typ), output drive strength, and jitter. It also supports 5V ±5%, making it compatible with mixed-voltage telecom platforms.

How is frame synchronization achieved on the DS21604N?

Frame synchronization on the DS21604N is achieved via the SYNCIN input, which aligns CLKOUT1, CLKOUT2, and SYNCOUT edges to an external 8 kHz (or integer subrate) reference. Phase lock completes within 50 ms, and alignment tolerances are documented in Figures 4-2 and 4-5 of the datasheet for DS21604N.

DS21604N Specifications

Product attributes: Attribute value

Manufacturer:: Analog Devices Inc./Maxim Integrated

Series:: -

Package/Case:: 8-DIP (0.300", 7.62mm)

Packaging:: Tube

Product Status:: Obsolete

Programmable:: Not Verified

Type:: Clock Rate Adapter

PLL:: Yes

Input:: Clock

Output:: Clock

Number of Circuits:: 1

Ratio - Input:Output:: 1:2

Differential - Input:Output:: No/No

Frequency - Max:: 8.192MHz

Divider/Multiplier:: Yes/No

Voltage - Supply:: 3.135V ~ 5.25V

Operating Temperature:: -40°C ~ 85°C

Mounting Type:: Through Hole

Grade:: -

Qualification:: -

Supplier Device Package:: 8-PDIP

DS21604N FAQ

1.How can I place an order for DS21604N through Aetrix?

Please submit a Request for Quotation (RFQ) for DS21604N 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 DS21604N reliable?

The price and inventory of DS21604N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS21604N is usually 5 days.

3.What payment methods are accepted for DS21604N?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS21604N transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for DS21604N?

DS21604N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your DS21604N 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 DS21604N?

For technical support, including DS21604N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS21604N requirements.

6.How does Aetrix verify that DS21604N is sourced from the original manufacturer or authorized distributors?

All DS21604N 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 DS21604N meets industry standards.

7.What is the process for return or replacement of DS21604N?

All DS21604N units undergo pre-shipment inspection (PSI). If there is an issue with DS21604N, 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 DS21604N part is unused and in its original packaging.

Return procedure for DS21604N:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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