simulation over temperature range +25°C to +107°C of SM6T10A, PSPICE model downloaded from STMicro site, is far from real behaviour. At +25°C, VBR = 10.12V for IR = 1 mA, at +107°C, VBR = 244.8µV for the same current. With alphaT = 7.3 10e-4/°C (see datasheet), at +107°C, VBR should be 10.12*1.06 = 10.73 V, behaviour confirmed by measurement.
