caravel/xschem/current_test.spice

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*---------------------------------------------------------------------------
* SPDX-FileCopyrightText: 2020 Efabless Corporation
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* SPDX-License-Identifier: Apache-2.0
*---------------------------------------------------------------------------
* Simple POR circuit for Caravel current mirror test
*-------------------------------------------------------------------
.lib /home/tim/projects/efabless/tech/SW/sky130A/libs.tech/ngspice/sky130.lib.spice tt
* Note: 20 resistors of length 25um connected in series
Xres1 vdda vin vss sky130_fd_pr__res_xhigh_po_0p69 l=500
Xres2 vin vss vss sky130_fd_pr__res_xhigh_po_0p69 l=149
* voltage sources at 0V for measuring current in each branch
Vm1 vssm1 vss DC=0
Vm2 vdda vddm2 DC=0
Vm3 vdda vddm3 DC=0
Vm4 vssm4 vss DC=0
Vm5 vssm5 vss DC=0
Vm6 vdda vddm6 DC=0
Vm7 vdda vddm7 DC=0
* D G S B
Xm1 casc1 vin vssm1 vss sky130_fd_pr__nfet_g5v0d10v5 w=2 l=0.8 m=1
Xc1 mir1 casc1 casc1 vdda sky130_fd_pr__pfet_g5v0d10v5 w=2 l=0.8 m=1
Xm2 mir1 mir1 vddm2 vdda sky130_fd_pr__pfet_g5v0d10v5 w=2 l=0.8 m=8
Xm3 mir2 mir1 vddm3 vdda sky130_fd_pr__pfet_g5v0d10v5 w=2 l=0.8 m=1
Xc2 casc2 casc1 mir2 vdda sky130_fd_pr__pfet_g5v0d10v5 w=2 l=0.8 m=1
Xm4 casc2 casc2 vssm4 vss sky130_fd_pr__nfet_g5v0d10v5 w=2 l=0.8 m=7
Xm5 casc3 casc2 vssm5 vss sky130_fd_pr__nfet_g5v0d10v5 w=2 l=0.8 m=1
Xc3 mir3 casc3 casc3 vdda sky130_fd_pr__pfet_g5v0d10v5 w=2 l=0.8 m=1
Xm6 mir3 mir3 vddm6 vdda sky130_fd_pr__pfet_g5v0d10v5 w=2 l=0.8 m=7
Xm7 mir4 mir3 vddm7 vdda sky130_fd_pr__pfet_g5v0d10v5 w=2 l=0.8 m=1
Xc4 vcap casc3 mir4 vdda sky130_fd_pr__pfet_g5v0d10v5 w=2 l=0.8 m=1
* Check branch currents in each mirror branch.
* 1st branch should be 240nA
* 2nd branch should be 30nA
* 3rd branch should be 4.3nA
* 4th branch should be 612pA
*
* Result: vin sits at 0.7590 (close to 0.7575 target)
* I(Vm1/2) = 202.80 nA
* I(Vm3/4) = 26.10 nA (should be /8) actually /7.77
* I(Vm5/6) = 4.58 nA (should be /7) actually /5.70
* I(Vm7) = 0.67 pA (should be /7) actually /6.80
*----------------------------
* Testbench circuit
*----------------------------
Vpwr vdda vss DC=3.3
Rgnd vss 0 0.01
Rload vcap vss 1MEG
*----------------------------
*----------------------------
* Testbench control
*----------------------------
.control
op
print V(vin)
print I(Vm1)
print I(Vm2)
print I(Vm3)
print I(Vm4)
print I(Vm5)
print I(Vm6)
print I(Vm7)
.endc
.end