Hi Walter, Please see my comments and questions below: (1) "This implies that AMI modeling assumes a small signal interface to the analog channel." Can you please clarify the meaning of "a small signal interface"? The only necessary assumption when representing a channel using impulse response is that the channel must be LTI. (2) "This also implies that the differential impedance of a Tx or Rx is constant over the operating range of the device." There are several possible cases of "impedance of a Tx or Rx". It could be the input or, the output or, the load impedance of Tx analog block. Please clarify which one is referred to by this statement. Same questions exist for Rx. Thanks, James Zhou QLogic Corp. From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Walter Katz Sent: Tuesday, January 17, 2012 1:16 PM To: IBIS-ATM Subject: [ibis-macro] Replacing BIRD 122 with "Reserved_Model" keyword in [External Model] All, I would like to extend BIRD 116 to allow the following for AMI [Model]s [External Model] Language ISS Reserved_Model AMI_Tstonefile_Tx|AMI_Tstonefile_Rx|AMI_Thevenin_Tx|AMI_Thevenin_Rx [End External Model] AMI modeling assumes that a channel can be represented by an Impulse Response. This implies that AMI modeling assumes a small signal interface to the analog channel. This also implies that the differential impedance of a Tx or Rx is constant over the operating range of the device. Note that any legacy IBIS model (IV, Vt curves, Series Pin), that when used in the real operating range of a SerDes channel (where AMI modeling is applicable) can be accurately represented by the following Thevenin Tx and Rx models. Reserved_Model AMI_Tstonefile_Tx [External Model] Language ISS Reserved_Model AMI_Tstonefile_Tx [End External Model] Is equivalent to: [External Model] Language ISS Corner Typ AMI_Tstonefile_Tx.cir AMI_Tstonefile_Tx Parameters Tstonefile = AMIfile(Tstonefile) | Tstonefile must be an AMI Model_Specific parameter Converter_Parameters Vhi = AMIfile(Voh) | Voh must be an AMI Model_Specific parameter Converter_Parameters Vlo = AMIfile(Vol) | Vol is 0 if it is not an AMI Model_Specific parameter Converter_Parameters Trf = 1.0ps Ports my_driveP my_driveN A_signal_pos A_signal_neg D_to_A D_drive my_driveP 0 Vlo Vhi Trf Trf Typ Non-Inverting D_to_A D_drive my_driveN 0 Vlo Vhi Trf Trf Typ Inverting [End External Model] AMI_Tstonefile_Tx.cir. .SUBCKT AMI_Tstonefile_Tx my_driveP my_driveN A_signal_pos A_signal_neg + Tstonefile="NA.s4p" Sdriver my_driveP my_driveN A_signal_pos A_signal_neg 0 MNAME=Smodel_name .MODEL Smodel_name S N=4 TSTONEFILE=Tstonefile .ends Reserved_Model AMI_Tstonefile_Rx [External Model] Language ISS Reserved_Model AMI_Tstonefile_Rx [End External Model] Is equivalent to: [External Model] Language ISS Corner Typ AMI_Tstonefile_Rx.cir AMI_Tstonefile_Rx Parameters Tstonefile = AMIfile(Tstonefile) Ports A_signal_pos A_signal_neg A_int_pos A_int_neg A_to_D D_receive A_int_pos A_int_neg -.02 .02 Typ [End External Model] AMI_Tstonefile_Rx.cir. .SUBCKT AMI_Tstonefile_Rx A_signal_pos A_signal_neg A_int_pos A_int_neg + Tstonefile="NA.s4p" Sdriver A_signal_pos A_signal_neg A_int_pos A_int_neg 0 MNAME=Smodel_name .MODEL Smodel_name S N=4 TSTONEFILE=Tstonefile .ends Reserved_Model AMI_Thevenin_Tx [External Model] Language ISS Reserved_Model AMI_Thevenin_Tx [End External Model] Is equivalent to: [External Model] Language ISS Corner Typ AMI_Thevenin_Tx.cir AMI Thevenin_Tx Parameters Rt = AMIfile(Rt) Parameters Rs = AMIfile(Rs) Parameters Cc = AMIfile(Cc) Parameters Vt = AMIfile(Vt) Parameters Cac = AMIfile(Cac) Parameters Rac = AMIfile(Rac) Parameters Rd = AMIfile(Rd) Parameters Cd = AMIfile(Cd) Parameters Trf = AMIfile(Trf) | Only AMI Model_Specific parameters Rt Rs Cc Vt Cac Rac Rd Cd defined in the | .ami file shall be passed as parameters to the subckt AMI Thevenin_Tx instance Converter_Parameters Vhi = AMIfile(Voh) | Voh must be an AMI Model_Specific parameter Converter_Parameters Vlo = AMIfile(Vol) | Vol is 0 if it is not an AMI Model_Specific parameter Converter_Parameters Trf = AMIfile(Trf) | Trf is 1p if it is not an AMI Model_Specific parameter Ports my_driveP my_driveN A_signal_pos A_signal_neg D_to_A D_drive my_driveP 0 Vlo Vhi Trf Trf Typ Non-Inverting D_to_A D_drive my_driveN 0 Vlo Vhi Trf Trf Typ Inverting [End External Model] AMI_Thevenin_Tx.cir .SUBCKT AMI_Thevenin_Tx my_driveP my_driveN A_signal_pos A_signal_neg + Rt=1Meg Rs=1Meg Cc=0. Vt=0. Cac=0. Rac=1Meg Rd=1Meg Cd=0. E_H E_my_driveP 0 VCVS my_driveP 0 1. E_L E_my_driveN 0 VCVS my_driveN 0 1. R_Rs_H E_my_driveP A_signal_pos R='Rs' R_Rs_L E_my_driveN A_signal_neg R='Rs' R_Rd A_signal_pos A_signal_neg R='Rd' C_Rd A_signal_pos A_signal_neg C='Cd' R_Rt_H A_signal_pos Vt R='Rt' R_Rt_H A_signal_neg Vt R='Rt' V_Vt Vt 0 DC='Vt' C_Cc_H A_signal_pos 0 C='Cc' C_CC_L A_signal_neg 0 C='Cc' R_ac A_signal_pos Nac R='Rac' C_ac A_signal_neg Nac C='Cac' .ends Reserved_Model AMI_Thevenin_Rx [External Model] Language ISS Reserved_Model AMI_Thevenin_Rx [End External Model] Is equivalent to: [External Model] Language ISS Corner Typ AMI_Thevenin_Rx.cir AMI_Thevenin_Rx Parameters Rt = AMIfile(Rt) Parameters Cc = AMIfile(Cc) Parameters Vt = AMIfile(Vt) Parameters Cac = AMIfile(Cac) Parameters Rac = AMIfile(Rac) Parameters Rd = AMIfile(Rd) Parameters Cd = AMIfile(Cd) |Only AMI Model_Specific parameters Rt Cc Vt Cac Rac Rd Cd defined in the |.ami file shall be passed as parameters to the subckt AMI Thevenin_Tx instance Ports A_signal_pos A_signal_neg A_int_pos A_int_neg A_to_D D_receive A_int_pos A_int_neg -.02 .02 Typ [End External Model] [External Model] AMI_Thevenin_Rx.cir. .subckt AMI_Thevenin_Rx A_signal_pos A_signal_neg A_int_pos A_int_neg + Rt=1Meg Cc=0. Vt=0. Cac=0. Rac=1Meg Rd=1Meg Cd=0. E_H A_int_pos 0 VCVS A_signal_pos 0 1. E_L A_int_neg 0 VCVS A_signal_neg 0 1. R_Rd A_signal_pos A_signal_neg R='Rd' C_Rd A_signal_pos A_signal_neg C='Cd' R_Rt_H A_signal_pos Vt R='Rt' R_Rt_H A_signal_neg Vt R='Rt' V_Vt Vt 0 DC='Vt' C_Cc_H A_signal_pos 0 C='Cc' C_CC_L A_signal_neg 0 C='Cc' R_ac A_signal_pos Nac R='Rac' C_ac A_signal_neg Nac C='Cac' .ends Walter Katz wkatz@xxxxxxxxxx<mailto:wkatz@xxxxxxxxxx> Phone 303.449-2308 Mobile 720.333-1107 ________________________________ This message and any attached documents contain information from QLogic Corporation or its wholly-owned subsidiaries that may be confidential. If you are not the intended recipient, you may not read, copy, distribute, or use this information. If you have received this transmission in error, please notify the sender immediately by reply e-mail and then delete this message.