how to design a constant current source with accurate absolute value？

:victory::victory::victory:

check this post,I hope it will help ya
http://www.eetop.cn/bbs/thread-94586-1-5.html

Current Mode Bandgap
Please visit the following website,
http://www.eetop.cn/bbs/thread-190594-1-1.html
This report includes detailed Hspice simuation and netlist files.
Contents
1. OP schematic sheet and netlist
2. Bandgap reference schematic sheet and netlist
3. Bandgap reference circuit: temperature vs. Vref simulation
4. Bandgap reference circuit: Transient simulation
5. Bandgap reference PSRR simulation
File name discription
1. bandgap.sp: temperature vs. reference voltage simulated file
2. bandgap_tran.sp: Bandgap tranient simulated file
3. bandgap_psrr.sp: Bandgap PSRR simulated file
Reference paper:Hironori Banba “A CMOS Bandgap Reference Circuit with Sub-1-V Operation” IEEE J. Solid-State Circuits, vol. 34, NO. 5, pp.670-673, MAY 1999
For analytical solution of Banba Bandgap Reference circuit, please visit the following website
http://www.eetop.cn/bbs/thread-184913-1-1.html
The original solution of Razavi's Problem 11.17 and 11.18 are wrong！Page 402~403
Hspice Model: please visit http://www.eetop.cn/bbs/thread-135217-1-2.html
Hi All
Your comments are always welcome！

thanks for sharing

thanks for sharing.