diff --git a/gf180mcu/openlane/gf180mcu_fd_sc_mcu7t5v0/config.tcl b/gf180mcu/openlane/gf180mcu_fd_sc_mcu7t5v0/config.tcl
index 2c61643..d8d0b9d 100644
--- a/gf180mcu/openlane/gf180mcu_fd_sc_mcu7t5v0/config.tcl
+++ b/gf180mcu/openlane/gf180mcu_fd_sc_mcu7t5v0/config.tcl
@@ -51,3 +51,4 @@
 set ::env(GPL_CELL_PADDING) {0}
 set ::env(DPL_CELL_PADDING) {0}
 
+set ::env(TRISTATE_CELL_PREFIX) "$::env(STD_CELL_LIBRARY)__bufz"
diff --git a/gf180mcu/openlane/gf180mcu_fd_sc_mcu9t5v0/config.tcl b/gf180mcu/openlane/gf180mcu_fd_sc_mcu9t5v0/config.tcl
index b0a2c1d..8c34ef3 100644
--- a/gf180mcu/openlane/gf180mcu_fd_sc_mcu9t5v0/config.tcl
+++ b/gf180mcu/openlane/gf180mcu_fd_sc_mcu9t5v0/config.tcl
@@ -51,3 +51,4 @@
 set ::env(GPL_CELL_PADDING) {0}
 set ::env(DPL_CELL_PADDING) {0}
 
+set ::env(TRISTATE_CELL_PREFIX) "$::env(STD_CELL_LIBRARY)__bufz"
diff --git a/sky130/openlane/sky130_fd_sc_hd/config.tcl b/sky130/openlane/sky130_fd_sc_hd/config.tcl
index 9abb7f9..e5dd71a 100755
--- a/sky130/openlane/sky130_fd_sc_hd/config.tcl
+++ b/sky130/openlane/sky130_fd_sc_hd/config.tcl
@@ -70,3 +70,5 @@
 # Determined from https://github.com/google/skywater-pdk-libs-sky130_fd_sc_hd/blob/ac7fb61f06e6470b94e8afdf7c25268f62fbd7b1/cells/clkbuf/sky130_fd_sc_hd__clkbuf_16__tt_025C_1v80.lib.json
 set ::env(CTS_MAX_CAP) 1.53169
 set ::env(DEFAULT_MAX_TRAN) 0.75
+
+set ::env(TRISTATE_CELL_PREFIX) "$::env(STD_CELL_LIBRARY)__ebuf"
diff --git a/sky130/openlane/sky130_fd_sc_hdll/config.tcl b/sky130/openlane/sky130_fd_sc_hdll/config.tcl
index 09a7475..9a34844 100755
--- a/sky130/openlane/sky130_fd_sc_hdll/config.tcl
+++ b/sky130/openlane/sky130_fd_sc_hdll/config.tcl
@@ -67,3 +67,5 @@
 # Determined from https://github.com/google/skywater-pdk-libs-sky130_fd_sc_hdll/blob/0694bd23893de20f5233ef024acf6cca1e750ac6/cells/clkbuf/sky130_fd_sc_hdll__clkbuf_16__tt_025C_1v80.lib.json
 set ::env(CTS_MAX_CAP) 1.03547
 set ::env(DEFAULT_MAX_TRAN) 0.75
+
+set ::env(TRISTATE_CELL_PREFIX) "$::env(STD_CELL_LIBRARY)__ebuf"
diff --git a/sky130/openlane/sky130_fd_sc_hs/config.tcl b/sky130/openlane/sky130_fd_sc_hs/config.tcl
index d2ae850..eed9de4 100755
--- a/sky130/openlane/sky130_fd_sc_hs/config.tcl
+++ b/sky130/openlane/sky130_fd_sc_hs/config.tcl
@@ -66,3 +66,5 @@
 set ::env(CTS_MAX_CAP) 1.8894300000
 set ::env(DEFAULT_MAX_TRAN) 0.75
 set ::env(FP_PDN_RAIL_WIDTH) 0.48
+
+set ::env(TRISTATE_CELL_PREFIX) "$::env(STD_CELL_LIBRARY)__ebuf"
diff --git a/sky130/openlane/sky130_fd_sc_ls/config.tcl b/sky130/openlane/sky130_fd_sc_ls/config.tcl
index 6657138..4f70f8f 100755
--- a/sky130/openlane/sky130_fd_sc_ls/config.tcl
+++ b/sky130/openlane/sky130_fd_sc_ls/config.tcl
@@ -69,3 +69,5 @@
 set ::env(CTS_MAX_CAP) 1.53169
 set ::env(DEFAULT_MAX_TRAN) 0.75
 set ::env(FP_PDN_RAIL_WIDTH) 0.48
+
+set ::env(TRISTATE_CELL_PREFIX) "$::env(STD_CELL_LIBRARY)__ebuf"
diff --git a/sky130/openlane/sky130_fd_sc_ms/config.tcl b/sky130/openlane/sky130_fd_sc_ms/config.tcl
index d7bc6e5..9275f4d 100755
--- a/sky130/openlane/sky130_fd_sc_ms/config.tcl
+++ b/sky130/openlane/sky130_fd_sc_ms/config.tcl
@@ -68,3 +68,5 @@
 set ::env(CTS_MAX_CAP) 1.53169
 set ::env(DEFAULT_MAX_TRAN) 0.75
 set ::env(FP_PDN_RAIL_WIDTH) 0.48
+
+set ::env(TRISTATE_CELL_PREFIX) "$::env(STD_CELL_LIBRARY)__ebuf"