Features
 High Performance Non-Blocking Switch Architecture
– 48-lane 12-port PCIe switch
• Six x8 ports switch ports each of which can bifurcate to two
x4 ports (total of twelve x4 ports)
– Integrated SerDes supports 5.0 GT/s Gen2 and 2.5 GT/s
Gen1 operation
– Delivers up to 48 GBps (384 Gbps) of switching capacity
– Supports 128 Bytes to 2 KB maximum payload size
– Low latency cut-through architecture
– Supports one virtual channel and eight traffic classes
 Standards and Compatibility
– PCI Express Base Specification 2.0 compliant
– Implements the following optional PCI Express features
• Advanced Error Reporting (AER) on all ports
• End-to-End CRC (ECRC)
• Access Control Services (ACS)
• Power Budgeting Enhanced Capability
• Device Serial Number Enhanced Capability
• Sub-System ID and Sub-System Vendor ID Capability
• Internal Error Reporting ECN
• Multicast ECN
• VGA and ISA enable
• L0s and L1 ASPM
• ARI ECN
 Port Configurability
– x4 and x8 ports
• Ability to merge adjacent x4 ports to create a x8 port
– Automatic per port link width negotiation
(x8 → x4 → x2 → x1)
– Crosslink support
– Automatic lane reversal
– Autonomous and software managed link width and speed
control
– Per lane SerDes configuration
• De-emphasis
• Receive equalization
• Drive strength
 Switch Partitioning
– IDT proprietary feature that creates logically independent
switches in the device
– Supports up to 12 fully independent switch partitions
– Configurable downstream port device numbering
– Supports dynamic reconfiguration of switch partitions
• Dynamic port reconfiguration — downstream, upstream
• Dynamic migration of ports between partitions
• Movable upstream port within and between switch partitions
 Initialization / Configuration
– Supports Root (BIOS, OS, or driver), Serial EEPROM, or
SMBus switch initialization
– Common switch configurations are supported with pin strapping
(no external components)
– Supports in-system Serial EEPROM initialization/programming
 Quality of Service (QoS)
– Port arbitration
• Round robin
– Request metering
• IDT proprietary feature that balances bandwidth among
switch ports for maximum system throughput
– High performance switch core architecture
• Combined Input Output Queued (CIOQ) switch architecture
with large buffers
 Multicast
– Compliant to the PCI-SIG multicast ECN
– Supports arbitrary multicasting of Posted transactions
– Supports 64 multicast groups
– Multicast overlay mechanism support
– ECRC regeneration support
 Clocking
– Supports 100 MHz and 125 MHz reference clock frequencies
– Flexible clocking modes
• Common clock
• Non-common clock
• Local port clock with SSC and port reference clock input
 Hot-Plug and Hot Swap
– Hot-plug controller on all ports
• Hot-plug supported on all downstream switch ports
– All ports support hot-plug using low-cost external I2C I/O
expanders
– Configurable presence detect supports card and cable applications
– GPE output pin for hot-plug event notification
• Enables SCI/SMI generation for legacy operating system
support
– Hot swap capable I/O
 Power Management
– Supports D0, D3hot and D3 power management states
– Active State Power Management (ASPM)
• Supports L0, L0s, L1, L2/L3 Ready and L3 link states
• Configurable L0s and L1 entry timers allow performance/
power-savings tuning
– Supports PCI Express Power Budgeting Capability
– SerDes power savings
• Supports low swing / half-swing SerDes operation
• SerDes optionally turned-off in D3hot
• SerDes associated with unused ports are turned-off
• SerDes associated with unused lanes are placed in a low
power state
 9 General Purpose I/O
 Reliability, Availability and Serviceability (RAS)
– ECRC support
– AER on all ports
– SECDED ECC protection on all internal RAMs
– End-to-end data path parity protection
– Checksum Serial EEPROM content protected
– Autonomous link reliability (preserves system operation in the
presence of faulty links)
– Ability to generate an interrupt (INTx or MSI) on link up/down
transitions
 Test and Debug
– On-chip link activity and status outputs available for Port 0
(upstream port)
– Per port link activity and status outputs available using
external I2C I/O expander for all other ports
– SerDes test modes
– Supports IEEE 1149.6 AC JTAG and IEEE 1149.1 JTAG
 Power Supplies
– Requires only two power supply voltages (1.0 V and 2.5 V)
Note that a 3.3V is preferred for VDDI/O
– No power sequencing requirements
 Packaged in a 27mm x 27mm 676-ball Flip Chip BGA with
1mm ball spacing

Description
Utilizing standard PCI Express Gen2 interconnect, the
PES48H12G2 provides the most efficient system interconnect switching
solution for applications requiring high throughput, low latency, and
simple board layout with a minimum number of board layers. It provides
48 GBps (384 Gbps) of aggregated, full-duplex switching capacity
through 48 integrated serial lanes, using proven and robust IDT technology.
Each lane is capable of 5 GT/s of bandwidth in both directions
and is fully compliant with PCI Express Base specification 2.0.
The PES48H12G2 is based on a flexible and efficient layered architecture.
The PCI Express layer consists of SerDes, Physical, Data Link
and Transaction layers in compliance with PCI Express Base specification
Revision 2.0. The PES48H12G2 can operate either as a store and
forward or cut-through switch. It supports eight Traffic Classes (TCs)
and one Virtual Channel (VC) with sophisticated resource management
to enable efficient switching and I/O connectivity for servers, storage,
and embedded processors with limited connectivity.
The PES48H12G2 is a partitionable PCIe switch. This means that in
addition to operating as a standard PCI express switch, the
PES48H12G2 ports may be partitioned into groups that logically
operate as completely independent PCIe switches. Figure 2 illustrates a
three partition PES48H12G2 configuration.