LT685CN - 5.5ns High-Speed ECL Comparator | Analog Devices
Référence : LT685CN ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $0 | $0,00 |
| 10 | $0 | $0,00 |
| 100 | $0 | $0,00 |
| 500 | $0 | $0,00 |
| 1 000 | $0 | $0,00 |
LT685CN Présentation
A comparator is an analog signal-processing semiconductor that evaluates two input voltages and produces a logic output indicating which input is higher. The LT685 belongs to the comparator hierarchy, where its differential inputs, complementary outputs, and ECL interface place it between general-purpose logic-level comparators and high-speed timing components used in instrumentation, communications, and data acquisition.
The main features of the LT685CN include its 5.5 ns typical propagation delay, complementary ECL outputs, 50-ohm transmission-line drive capability, low input offset, output latch capability, and compatibility with the AM685 family. Its differential input structure supports balanced signal comparison, while the complementary outputs allow direct use in systems requiring both true and inverted decisions. The latch function can hold the comparator state for applications that need sampled or stored decisions rather than continuous tracking.
The LT685 uses an older high-speed ECL-compatible architecture intended for short propagation-delay operation and controlled point-to-point interconnects. Its output current capability is specified for driving transmission lines terminated in 50 ohms, making board-level routing and termination more important than with ordinary CMOS or TTL comparators. Differential inputs can also reduce sensitivity to common-mode noise when the surrounding analog signal path is properly laid out and referenced.
Typical applications include pulse-width and pulse-height discrimination, high-speed threshold detection, ECL interface circuits, analog-to-digital front ends, communications equipment, laboratory instrumentation, and timing recovery systems. The 16-pin PDIP package is through-hole and suitable for legacy or prototype boards where the comparator must be inserted or socketed rather than mounted in a compact surface-mount assembly.
When designing a circuit around the LT685CN, verify input common-mode range, output termination, supply requirements, latch timing, and the required propagation-delay margin. Keep high-speed traces short, use controlled impedance where practical, and terminate ECL-compatible outputs according to the system’s transmission-line topology. The available verified data does not establish exact input common-mode limits, supply-current values, pin-level timing, or package temperature limits.
This product record combines the verified LT685 and LT685CN manufacturer information, distributor availability references, and cross-reference search results with practical guidance for high-speed comparator implementation. It also distinguishes documented drop-in alternatives from package or functional similarities so that engineers can make a replacement decision based on actual pin and parameter evidence.
Alternatives de remplacement direct pour LT685CN — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec LT685CN (même facteur de forme et même empreinte) — différant par Latch Function, Package, RoHS Status.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
AM685
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LT685CN#PBF
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LT685MJ
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
AM685/BEA
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LT1016CN8
✅ Remplacement direct ⚠️ Spécifications non vérifiées✓ En stock
$4.47 / unité
Voir la fiche technique →LT685CN Valeurs maximales et caractéristiques électriques
| Comparator Type | High-speed voltage comparator |
| Typical Propagation Delay | 5.5 ns |
| Input Configuration | Differential inputs |
| Configuration de sortie | Complementary outputs |
| Logic Compatibility | ECL-compatible |
| Transmission-Line Drive | 50 ohm terminated lines |
| Input Offset | Low offset voltage |
| Résolution | High resolution |
| Latch Function | Output latch capability |
| Hysteresis Control | External hysteresis-control pin |
| Boîtier | 16-pin PDIP |
| Package Pin Count | 16 pins |
| Lead-Finish / Ordering Suffix | CN |
| Statut RoHS | unknown |
| REACH Status | unknown |
| AEC-Q100 Qualification | not_applicable |
Guide de configuration des broches du LT685CN 16 pins
Configuration des broches du LT685CN (boîtier 16 pins). Ce composant analogique comporte des broches d'entrée, de sortie et d'alimentation. Consultez la fiche technique du fabricant pour les configurations des broches d'annulation d'offset, de compensation et d'activation. Idéal pour le conditionnement de signaux et les circuits amplificateurs.
Aucune donnée de brochage détaillée disponible pour LT685CN.
Consultez la fiche technique pour la configuration complète des broches.
Applications typiques
LT685CN convient pour 7 applications: High-Speed Pulse Detection, Analog-to-Digital Front End, Timing and Clock Qualification, Communications Line Interface, Laboratory Instrumentation, Data Acquisition Triggering, ECL Logic Interfacing.
High-Speed Pulse Detection
The LT685CN fits pulse-width, pulse-height, and timing-threshold detection because its documented typical propagation delay is 5.5 ns and its differential inputs support comparison against a reference signal. Place the comparator close to the source and receiver, route the differential pair with controlled geometry, and terminate the ECL-compatible output according to the board’s transmission-line arrangement. The latch and external hysteresis functions help capture short events and prevent repeated switching near the threshold. Exact input common-mode voltage and output-level limits must be confirmed from the manufacturer datasheet before setting the analog operating point.
Recommandé
Analog-to-Digital Front End
Use the LT685CN when a sensor or conditioned analog signal must be converted into a fast decision before an ADC or digital processing block. Its low input offset and high resolution support precise thresholding, while the 5.5 ns typical propagation delay minimizes dead time between crossing events and digital response. The complementary ECL-compatible outputs can feed compatible logic directly or through appropriate level translation. Because the verified data does not specify the full input common-mode range, validate biasing, noise immunity, and output compatibility against the actual ADC interface before layout release.
Recommandé
Timing and Clock Qualification
The LT685CN is suitable for high-speed timing qualification when a clock or pulse must be checked against an adjustable threshold and converted into complementary logic decisions. Its 5.5 ns typical delay provides timing margin in many high-speed laboratory and communications systems, while the output latch allows a decision to be held for later sampling. External hysteresis can reduce chatter when the monitored transition is slow or noisy. Keep the threshold source and comparator inputs short, preserve the differential pair geometry, and use a defined termination network because output ringing can affect downstream timing accuracy.
Recommandé
Communications Line Interface
The complementary ECL-compatible outputs and documented 50-ohm transmission-line drive capability make the LT685CN relevant to legacy high-speed communications and test-interface circuits. It can provide a binary decision from a differential receive signal before the signal is passed into compatible digital logic. The implementation must account for line impedance, connector and trace discontinuities, return-path continuity, and the receiving device’s ECL thresholds. Because the verified information does not provide complete output voltage or supply-current values, use the manufacturer datasheet for termination and level-compatibility calculations rather than assuming generic ECL numbers.
Recommandé
Laboratory Instrumentation
The LT685CN can serve as a fast decision element in laboratory measurement systems that need to convert an analog waveform into a trigger or threshold event. Its differential inputs, complementary outputs, latch, and external hysteresis controls support repeatable event detection when the board is properly terminated and referenced. Use short analog paths, maintain a stable reference return, and probe the output with an appropriate high-impedance or terminated measurement setup. The verified data identifies the 16-pin PDIP package and legacy through-hole form factor, which is useful for prototype and educational instrumentation, although modern production designs should check lifecycle and sourcing status.
Recommandé
Data Acquisition Triggering
For data-acquisition systems, the LT685CN can generate a fast trigger when an analog input crosses a programmed threshold. The 5.5 ns typical propagation delay helps reduce uncertainty between the measured signal event and the acquisition trigger, while the complementary outputs support both active-high and active-low trigger paths. The latch is useful when the acquisition system needs a held decision, and external hysteresis helps prevent noisy or slowly changing signals from producing repeated triggers. Verify input biasing, threshold accuracy, output levels, and supply requirements against the actual front-end and acquisition ICs.
Recommandé
ECL Logic Interfacing
The LT685CN is directly relevant to legacy systems that use ECL-compatible logic levels and require a high-speed comparator with complementary outputs. It can compare differential analog conditions and present complementary results to compatible receivers without first converting through a general-purpose CMOS logic family. A successful interface depends on correct supply sequencing, signal-return continuity, termination, and output loading. The verified manufacturer information confirms ECL compatibility and 50-ohm line-drive capability but does not provide the complete voltage-level table, so verify those values in the LT685 datasheet and receiver specifications before releasing the circuit.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour LT685CN — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | AM685 | LT685CN#PBF | LT685MJ | AM685/BEA |
|---|---|---|---|---|---|
| Package | 16-pin PDIP | 16-pin PDIP | 16-pin PDIP | 16-pin PDIP | 16-pin PDIP |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Product Type | High-speed voltage comparator | Comparator | High-speed comparator | Comparator alternative | Comparator |
Principaux différenciateurs
- Documented ultrafast decision speed (vs AM685)
- Complementary ECL-compatible outputs (vs LT685CN#PBF)
- External hysteresis and output latch (vs LT685MJ)
- 50-ohm transmission-line drive capability (vs AM685/BEA)
Notes de conception
Keep the differential input path short and preserve matched geometry from the signal source to the LT685CN inputs. High-speed comparators can respond to trace mismatch, discontinuities, and return-path impedance discontinuities as if they were input signals. Use a continuous ground or reference plane where practical, minimize stubs, and place hysteresis and threshold components close to the relevant pins. The verified data confirms a differential-input, high-speed ECL-compatible design but does not provide a complete PCB reference layout, so follow the manufacturer’s recommended application circuit.
Treat LT685CN outputs as transmission-line outputs rather than ordinary low-speed logic outputs. The manufacturer states that the output current is adequate for lines terminated in 50 ohms. Therefore, determine whether the board uses series termination, parallel termination, or another ECL topology, and keep the connection length, return path, and receiver loading controlled. Incorrect termination can create ringing, overshoot, false triggering, or degraded apparent propagation delay even when the comparator itself is operating correctly.
Do not assume that a related comparator name guarantees drop-in compatibility. The verified cross-reference results identify AM685, LT685CN#PBF, LT685MJ, and AM685/BEA as related references, but they do not provide complete pin-level and timing equivalence for every candidate. Before replacing LT685CN, compare input common-mode range, supply voltage, output levels, latch polarity, hysteresis connection, pinout, propagation delay, and package dimensions against the manufacturer datasheets.
Verify the actual supply configuration and supply-current requirements before powering the LT685CN. Those values are not included in the supplied verified search results, and a high-speed ECL-compatible device should not be operated using assumptions borrowed from CMOS or TTL logic. Confirm the output voltage levels, input bias, termination return, and startup sequence against the datasheet and the receiving logic family. The 5.5 ns propagation-delay specification should not be used as a substitute for a complete timing budget.
Informations de conformité
The supplied verified web data does not state RoHS, REACH, lead-free, halogen-free, conflict-minerals, or AEC-Q100 status. No compliance claim has been inferred.
