11.4.6SAS transmitters and receivers

A typical SAS differential copper transmitter and receiver pair is shown in Figure 20. The receiver is AC coupling to eliminate ground shift noise.

Figure 20. SAS transmitters and receivers

11.4.7Power

The drive receives power (+5 volts and +12 volts) through the SAS device connector.

Three +12 volt pins provide power to the drive, 2 short and 1 long. The current return for the +12 volt power supply is through the common ground pins. The supply current and return current must be distributed as evenly as possible among the pins.

Three +5 volt pins provide power to the drive, 2 short and 1 long. The current return for the +5 volt power supply is through the common ground pins. The supply current and return current must be distributed as evenly as possible among the pins.

Current to the drive through the long power pins may be limited by the system to reduce inrush current to the drive during hot plugging.

11.5SIGNAL CHARACTERISTICS

This section describes the electrical signal characteristics of the drive’s input and output signals. See Table 24 for signal type and signal name information.

11.5.1Ready LED Out

The Ready LED Out signal is driven by the drive as indicated in Table 25.

Table 25 Ready LED Out conditions

NORMAL COMMAND ACTIVITY

 

LED STATUS

 

 

 

Ready LED Meaning bit mode page 19h

0

 

1

 

 

 

 

Drive stopped, not ready, and no activity

Off

 

Off

 

 

 

 

Drive stopped, not ready, and activity

On

 

On

(command executing)

 

 

 

 

 

 

 

Drive started, ready, and no activity

On

 

Off

 

 

 

 

Drive started, ready, and activity

Off

 

On

(command executing)

 

 

 

 

 

 

 

Drive transitioning from not-ready state to

 

Blinks steadily

ready state or the reverse.

(50% on and 50% off, 0.5 seconds on and off for 0.5 seconds)

 

 

 

FORMAT UNIT in progress,

 

Toggles on/off

 

 

 

 

The Ready LED Out signal is designed to pull down the cathode of an LED. The anode is attached to the proper +3.3 volt supply through an appropriate current limiting resistor. The LED and the current limiting resistor are external to the drive. See Table 26 for the output characteristics of the LED drive signals.

Table 26 LED drive signal

STATE

TEST CONDITION

OUTPUT VOLTAGE

 

 

 

 

 

LED off, high

0 V ≤ VOH ≤ 3.6 V

-100 μA < IOH < 100 μA

 

LED on, low

IOL = 15 mA

0 ≤ VOL ≤ 0.225 V

 

PULSAR.2 SAS PRODUCT MANUAL, REV. C

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Seagate ST200FM0012, ST100FM0012 SAS transmitters and receivers, Power, Ready LED Out conditions, LED drive signal
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ST800FM0002, ST100FM0002, ST200FM0002, ST400FM0012, ST800FM0032 specifications

The Seagate ST100FM0012, ST800FM0012, ST400FM0042, ST400FM0002, and ST100FM0052 are high-performance hard drives designed for enterprise applications, offering advanced features and reliability for demanding workloads.

The ST100FM0012 is a 10TB hard drive that strikes a balance between capacity and performance. It utilizes a 7200 RPM spindle speed and features a 256MB cache, enabling efficient data access and enhanced read/write performance. With Seagate’s AgileArray technology, the ST100FM0012 is optimized for NAS environments, providing multi-drive reliability and error recovery.

The ST800FM0012 is an 8TB variant that shares many features with its 10TB counterpart but is tailored for organizations needing robust storage without reaching the highest tier of capacity. Its dual-plane rotational vibration technology minimizes vibration in multi-drive systems, ensuring sustained performance over prolonged use. This makes it an excellent choice for virtualization and data-intensive applications.

The ST400FM0042 offers a 4TB capacity suited for smaller enterprise needs or as a backup solution. With an impressive performance profile, including a 7200 RPM speed and 128MB cache, it accommodates both sequential and random workloads with ease. This drive stands out with its PowerChoice technology, allowing users to manage power consumption and reduce operational costs.

Another 4TB option, the ST400FM0002, is particularly designed for hybrid configurations, pairing the fast access of the hard drive with the speed of SSDs. It features Seagate's advanced thermal management technologies, ensuring optimal operating temperatures and performance stability during intensive workloads.

The ST100FM0052 rounds out the lineup with a 10TB capacity but is specifically aimed at surveillance applications. It supports a workload rate of 180TB per year, making it ideal for always-on recording scenarios. The drive is built with optimized firmware, which ensures enhanced performance in write-intensive environments, essential for video recording and security systems.

All these drives are equipped with Seagate’s proprietary technologies, including data recovery services and built-in data protection features, ensuring data integrity and security. The drives are built for durability, reliability, and high performance in mission-critical environments, making them indispensable components of modern enterprise data storage solutions. With capacities ranging from 4TB to 10TB, they cater to varying storage needs across different sectors.
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