IBIS Models
 Altera® IBIS models are generated from HSPICE models and are based on either IBIS version 2.1, 3.2, or 4.1. The newer Altera device family models, such as Stratix® III and Cyclone® III IBIS models are generated with IBIS version 4.1. For models of Stratix II GX, Stratix II, Stratix GX, Stratix, Hardcopy® II, Hardcopy Stratix, Cyclone II, Cyclone, MAX® II, Mercury™, APEX™ II, APEX 20KC, and some APEX 20KE devices, IBIS models are generated with IBIS version 3.2. The rest of the device models are generated with IBIS version 2.1.
Multi-Voltage Support
Altera devices support multiple voltages (VCCIO), and there are separate IBIS models for each of the supported voltages. To simplify the model identification and the corresponding voltage level, the following model names are used:
- model_name_5 = 5.0-V VCCIO
- model_name_33 = 3.3-V VCCIO
- model_name_30= 3.0-V VCCIO
- model_name_2 or model_name_25 = 2.5-V VCCIO
- model_name_1 or model_name_18 = 1.8-V VCCIO
- model_name_15 = 1.5-V VCCIO
- model_name_12 = 1.2-V VCCIO
Slew Rate Control
Most Altera devices have the option of turning the slew rate on and off. The slew rate is turned on in files with an "s" or "slew" suffix . Likewise, the slew rate is turned off in files without an "s" or "slew" suffix in the signal/model name. For example:
- model_name = slew rate off
- model_name_s or model_name_slew = slew rate on
The latest devices such as Cyclone III and Stratix III devices support programmable slew rate control. Cyclone III devices support three slew rate settings: slow (s), medium (m), and fast (f) for each supported I/O standard. Stratix III devices support four slew rate settings: slow (s0), medium (s1), medium fast (s2), and fast (s3). The suffix of an IBIS model name indicates the slew rate setting. For example:
-
model_name = without slew rate control support
-
model_name_m = with medium slew rate setting
-
model_name_s2 = with medium fast slew rate setting
PCI Clamp Diode
Most Altera devices have the option of turning the PCI clamp diode on and off. The PCI clamp-diode is enabled in files with a "p" or "pci" suffix in the signal/model name. Likewise, the PCI clamp-diode is disabled in files without a "p" or "pci" suffix in the signal/model name. For example:
- model_name = PCI clamp diode off
- model_name_p or model_name_pci = PCI clamp diode on
Corner Case Support
Altera IBIS models support all three corner cases: typical, minimum, and maximum. Each corner is defined by its specific voltage, process, and temperature range. The corner case information is available within the Altera IBIS model.
Supported I/O Standards
Altera IBIS models support a variety of I/O standards, including:
- 3.3-V LVTTL/ LVCMOS
- 3.0-V LVTTL/ LVCMOS
- 2.5-V LVTTL/ LVCMOS
- 1.8-V LVTTL/ LVCMOS
- 1.5-V LVTTL/LVCMOS
- 1.2-V LVTTL/LVCMOS
- SSTL-3
- SSTL-2
- SSTL-18
- SSTL-15
- GTL+
- HSTL-18
- HSTL-15
- HSTL-12
- 3.3-V PCI
- 3.3-V PCI-X
- 3.3-V PCML
- 3.0-V PCI
- 3.0-V PCI-X
- LVDS
- RSDS
- PPDS
- Mini-LVDS
- LVPECL
- HyperTransport™ (HT)
- CTT
Altera IBIS model names specify the supported I/O standard. The following examples show the I/O standard indication in the model name for several devices:
- 2c_hstl18c2_cio_d18 represents a Cyclone II device model at column I/O bank with HSTL-18 class II standard
- 1s_ttl33_io_d4 represents a Stratix device model with 3.3-V LVTTL standard
- apex2_sstl2_in represents an APEX II device input model with 2.5-V SSTL-2 standard
Programmable Driver Current Strength
For newer Altera devices such as Cyclone series, Stratix series, and Hardcopy series, the drivers have different current strengths at various VCCIO levels. To distinguish between the models, each model name specifies the driver’s current strength, the VCCIO level, and the I/O standard. For example, the model name apex2_ttl_18v_4ma_s specifies the following:
- APEX II device model
- LVTTL I/O driver
- VCCIO = 1.8 V
- Driver current strength = 4 mA
- Slew rate control option on
On-Chip Termination
Some Altera devices support on-chip termination (OCT). The Altera device IBIS models that support OCT use the following model names:
Programmable Pre-Emphasis
The dedicated LVDS transmitters on Cyclone III and Stratix III devices support programmable pre-emphasis. Cyclone III devices support two programmable pre-emphasis settings (on and off), while Stratix III devices support four programmable pre-emphasis settings: zero, low, medium, and high. The suffix of an IBIS model indicates the pre-emphasis setting. For example:
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model_name_off = without pre-emphasis setting
-
model_name_on = with pre-emphasis setting
-
model_name_p1 = with low pre-emphasis setting
Programmable Differential Output Voltage (VOD)
Stratix III devices support four programmable VOD settings: low, medium low, medium high, and high. The suffix of an IBIS model indicates the pre-emphasis setting. For example:
Package RLC Values
Altera provides the package RLC values for each device family on the IBIS Models home page.
IBIS Output File Generation with Quartus II Software
Quartus® II software version 2.0 and later automatically generates an IBIS output file to perform board-level signal integrity verification using EDA tools. For more information on generating IBIS output files with Quartus II software, see Generating IBIS Files With Quartus.
Related IBIS Links
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