3.5.1 Drain Saturation Voltage Calculations

If $BULKMOD = 0$

$D_{mobs} = 1 + UA(T) \cdot (E_{effs})^{EU} + \dfrac{UD(T)}{ \Bigg[ \dfrac{1}{2} \cdot \Bigg( 1 + \dfrac{q_{is}}{1e^{-2} / C_{ox} } \Bigg) \Bigg]^{UCS(T)} }$

If $BULKMOD = 1$

$D_{mobs} = 1 + (UA(T) + UC(T) \cdot V_{eseff}) \cdot (E_{effs})^{EU} + \dfrac{UD(T)}{ \Bigg[ \dfrac{1}{2} \cdot \Bigg( 1 + \dfrac{q_{is}}{1e^{-2} / C_{ox} } \Bigg) \Bigg]^{UCS(T)} }$

$(3.304)$

$D_{mobs} = \dfrac{D_{mobs}}{U0MULT} \qquad (3.305)$

If $RDSMOD = 0$ then

$R_{ds,s} = \dfrac{1}{ \Big[ W_{eff0}(\mu m) \Big]^{WR_i}} \cdot \Bigg( RDSWMIN(T) + \dfrac{RDSW(T)}{1 + PRWGS_i \cdot q_{is}} \Bigg) \qquad (3.306)$

If $RDSMOD = 1$ then

$R_{ds,s} = 0 \qquad (3.307)$

If $RDSMOD = 2$ then

$R_{ds,s} = \dfrac{1}{ \Big[ W_{eff0}(\mu m) \Big]^{WR_i}} \cdot \Bigg( RS_{geo} + RD_{geo} + RDSWMIN(T) + \dfrac{RDSW(T)}{1 + PRWGS_i \cdot q_{is}} \Bigg) \qquad (3.308)$

$E_{sat} = \dfrac{2 \cdot VSAT(T)}{\mu_0 (T) / D_{mobs}} \qquad (3.309)$

$E_{satL} = E_{sat} \cdot L_{eff} \qquad (3.310)$

Here, $RS_{geo}$ and $RD_{geo}$ are geometry dependent (bias indepedent) part of source and drain resistances. In $RDSMOD = 2$ they are included in $R_{ds,s}$ calculation and no extra node is created. See Section 3.15 for details.

If $R_{ds,s} = 0$ then

$V_{dsat} = \dfrac{E_{satL} \cdot KSATIV_i \cdot \Big( V_{gsfbeff} - \psi_s + 2 \frac{kT}{q} \Big)}{E_{satL} + KSATIV_i \cdot \Big( V_{gsfbeff} - \psi_s + 2 \frac{kT}{q} \Big)} \qquad (3.311)$

Else,

$WVC_{ox} = W_{eff0} \cdot VSAT(T) \cdot C_{ox} \qquad (3.312)$

$T_a = 2 \cdot WVC_{ox} \cdot R_{ds,s} \qquad (3.313)$

$T_b = KSATIV_i \cdot \Big( V_{gsfbeff} - \psi_s + 2 \frac{kT}{q} \Big) \cdot (1 + 3 \cdot WVC_{ox} \cdot R_{ds,s}) + E_{satL} \qquad (3.314)$

$\begin{aligned} T_c &= KSATIV_i \cdot \Big( V_{gsfbeff} - \psi_s + 2 \frac{kT}{q} \Big) \\ &\times \Big[ E_{satL} + T_a \cdot KSATIV_i \cdot \Big( V_{gsfbeff} - \psi_s + 2 \frac{kT}{q} \Big) \Big] \qquad (3.315) \end{aligned}$

$V_{dsat} = \dfrac{T_b - \sqrt{T_b^2 - 2 T_a T_c}}{T_a} \qquad (3.316)$

$V_{dseff} = \dfrac{V_{ds}}{ \Bigg[ 1 + \Big( \dfrac{V_{ds}}{V_{dsat}} \Big)^{MEXP(T)} \Bigg]^{1/MEXP(T)}} \qquad (3.317)$