Zeynep Toprak Deniz

A 78mW 11.1Gb/s 5-tap DFE receiver with digitally calibrated current-integrating summers in 65nm CMOS

Extending data rates to meet the I/O needs of future computing and network systems is complicated by limited channel bandwidth. While a DFE [1] can be used to compensate channel distortion, its power dissipation reduces link energy efficiency, which is vitally important in complex systems. One way of reducing DFE power consumption is to use current-integrating summers [2–5]. Previously published current-integrating DFEs operating above 5Gb/s [3, 5] were demonstrated on simple test chips lacking support circuitry for CDR and DFE adaptation functions. The architecture presented here includes additional data paths based on current-integrating summers to realize a fully integrated RX with CDR and continuous DFE adaptation. The design also features a digital calibration loop for setting the summer bias currents so that high performance is achieved over process variations and different data rates.

The POWER8 TM processor: Designed for big data, analytics, and cloud environments

POWER8™ delivers a data-optimized design suited for analytics, cognitive workloads, and todays exploding data sizes. The design point results in a 2.5x performance gain over its predecessor, POWER7+™, for many workloads. In addition, POWER8 delivers the efficiency demanded by cloud computing models and also represents a first step toward creating an open ecosystem for server innovation.

5.1 POWER8 TM : A 12-core server-class processor in 22nm SOI with 7.6Tb/s off-chip bandwidth

The 12-core 649mm2 POWER8™ leverages IBMs 22nm eDRAM SOI technology [1], and microarchitectural enhancements to deliver up to 2.5× the socket performance [2] of its 32nm predecessor, POWER7+™ [3]. POWER8 contains 4.2B transistors and 31.5μF of deep-trench decoupling capacitance. Three thin-oxide transistor Vts are used for power/performance tuning, and thick-oxide transistors enable high-voltage I/O and analog designs. The 15-layer BEOL contains 5-80nm, 2-144nm, 3-288nm, and 3-640nm pitch layers for low-latency communication as well as 2-2400nm ultra-thick-metal (UTM) pitch layers for low-resistance distribution of power and clocks.

Root cause identification of an hard-to-find on-chip power supply coupling fail

In this paper, we will present a diagnostic test case of a hard-to-find fail condition causing an unexpected partial power on of a chip fabricated in IBM 65 nm bulk technology. In particular, we will describe the fail condition as well as the combined use of electrical testing, optical methodologies, and detailed circuit analysis that were used to reach a successful root cause identification of the problem. In addition, we will show how high resolution mapping of the Light Emission from Off-State Leakage Current (LEOSLC) from the chip was instrumental in leading the investigative effort to the right root cause. The problem was successfully traced to a p-FET used for IDDQ measurement during manufacturing test that caused an undesirable coupling path. Fortunately this specific configuration was unique to this particular design and was easy to fix with a single mask change.