Bonnie,
Open drain means there is no pullup in the IO. Given the circuit below , I
w3ould not expect to see the circuit rise to a 1 except via leakage
currents. Put a pullup resistor on the output pin.
Doug
_____
From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf
Of Xuefeng Chen
Sent: Thursday, October 14, 2010 12:48 AM
To: Baker, Bonnie; Muranyi, Arpad; ibis-users@eda.org
Subject: RE: [IBIS-Users]: Using HSPICE to run IBIS model
Hi Bonnie,
I am sure HSPICE supports all kinds of IBIS buffer types except external
model of VERILOG-AMS or VHDL-A(MS).
From the mail without the ibis file, it’s hard to figure out the issue.
Would you like contact HSPICE related AC or CAE for help.
Thanks,
Xuefeng
From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf
Of Baker, Bonnie
Sent: 2010年10月14日 11:53
To: Muranyi, Arpad; ibis-users@eda.org
Subject: [IBIS-Users]: Using HSPICE to run IBIS model
I am using Hspice to run IBIS and comparing it to a Spice simulation. The
Spice simulates the buffer well but the Hspice program is having problems.
My buffer type is I/O_open_drain.
The circuit diagram is:
-------------
I/O / R=0.5 L=2,5e-9
Open- /-----------/\/\/\/\-------|------/\_/\_/\_/\---------|---------O
output
Drain / |
|
Buffer / ---
---- ------------ --- C=1e-12 ---- C=5e-12 | | GND GND The I/O buffer is driven with a rail to rail input signal. The output signal does to reach the rail as expected. It actually looks like: ---------------------expected-output-high--------------------------------- ----------------- _______ _______/ _______/ _____/ ___/ __/ _/ / / / __/______________________________________________________ I expect ---------------------expected-and-actual-output-high---------------------- ---------------------------- / / / / / / / / / / / __/______________________________________________________ It appears as if Hspice does not recognize the fact that this buffer is open drain. Has anyone else experienced this and is the a work around? The Hspice netlist is: * * HSPICED IBIS I/O open drain BUFFER TEST BENCH * Temperature .TEMP 27 * POWER SUPPLIES and SIGNAL VOLTAGES VVCC VCC 0 DC=VCC VGND GND 0 DC=GND *PARAMETER DEFINITIONS .PARAM GND = 0V .PARAM VCC = VCC_typ .PARAM VCC_typ = 1.8 * Simulation Options .OPTIONS ACCT ACCURATE NOPAGE OPTS POST SCALE=1e-6 .OPTIONS METHOD=GEAR *=========TRANSIENT ANALYSIS sim======== .TRAN 0.1e-9 13000e-9 START =0.0e-9 * TD VIN_ibis IN_ibis GND PULSE VCC GND 0ps 0.01ns 0.01ns 149.99ns 300n *******************AC LOAD************** B_IO nd_pu nd_pd Out_ibis IN_ibis nd_en SDA_signal nd_pc nd_gc + file = 'tsc2014_nokia_3.ibs' model = 'SDA_1' + typ = typ power = on + buffer = 6 + ramp_fwf=1 ramp_rwf=1 Rpcb Out_ibis n1_pcb 0.50 Lpcb n1_pcb OUT_pcb_ibis 2.5e-9 Cpcb n1_pcb GND 1e-12 Cpcbload OUT_pcb_ibis GND 5e-12 Bonnie -- This message has been scanned for viruses and dangerous content by <http://www.mailscanner.info/> MailScanner, and is believed to be clean. -- This message has been scanned for viruses and dangerous content by <http://www.mailscanner.info/> MailScanner, and is believed to be clean. -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. -------------------------------------------------------------------- |For help or to subscribe/unsubscribe, e-mail majordomo@eda-stds.org |with the appropriate command message(s) in the body: | | help | subscribe ibis <optional e-mail address, if different> | subscribe ibis-users <optional e-mail address, if different> | unsubscribe ibis <optional e-mail address, if different> | unsubscribe ibis-users <optional e-mail address, if different> | |or e-mail a request to ibis-request@eda-stds.org. | |IBIS reflector archives exist under: | | http://www.eda-stds.org/pub/ibis/email_archive/ Recent | http://www.eda-stds.org/pub/ibis/users_archive/ Recent | http://www.eda-stds.org/pub/ibis/email/ E-mail since 1993Received on Thu Oct 14 04:55:26 2010
This archive was generated by hypermail 2.1.8 : Thu Oct 14 2010 - 04:56:03 PDT