ADR3450, increase output capability

Question

Hello friends, 
 I need around 15-20mA stable 5.000V reference for powering A1301, a ratiometric hall sensor. Since the project has low budget, I choose ADR3450 and plan to increase output capability with something similar that shown in datasheet: 
 
 I've done some simulation Multisim but since no support for ADR3450 spice model, I had to choose ADR3425, a 2.5V reference like this: 
 
 The question is: This circuit works also for 5V when powered from 5.5V supply? ADR itself has a very low dropout, but what about when boosting with NMOS? Can circuit be improved if necessarily? 
 Thanks very much in advance for comments.

FormerMember · Accepted Answer

zuzu, 
 Several things. 
 Note in the data sheet, the op amp is running on +16V so the output has enough swing to drive the MOSFET. 
 The A301 data sheet 
 http://www.tekscan.com/pdf/A301-force-sensor.pdf 
 is very poor, but looks like a variable resistor. It says the max recommended current is 2.5 mA, well 
 within the ADR3450 spec without extra circuitry (and cost) 
 There are several ways of measuring resistance. For two ways, see data sheets for 
 AD7793 and AD5933. 
 Harry)

FormerMember · Answer

zuzu, 
 I was looking at the A301 data sheet, instead of the A1301 data sheet. 
 The A1301 has a ratiometric output, so you don't need any reference at all. 
 Something like figure 2-17 should be good: 
 http://www.analog.com/static/imported-files/seminars_webcasts/49470200sscsect2.PDF 
 If you have a differential input on the ADC, just use a 5k/5k divider from the "5V" supply to ground 
 and drive the VIN- input. 
 Harry

EZAdministrator · Answer

This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

Thank you,
EZ Admin

Partner Forums

Partner Libraries

Products Mentioned

ADR3450, increase output capability