Datasheet MCP1501 (Microchip) - 5

MCP1501
1.1 Terminology 1.1.1 OUTPUT VOLTAGE Output voltage is the reference voltage that is available
on the OUT pin. 1.1.2 INPUT VOLTAGE The input voltage (VIN) is the range of voltage that can
be applied to the VDD pin and still have the device
produce the designated output voltage on the OUT pin. 1.1.3 TEMPERATURE COEFFICIENT
(TCOUT) The output temperature coefficient or voltage drift is a
measure of how much the output voltage will vary from
its initial value with changes in ambient temperature.
The value specified in the electrical specifications is
measured as shown in Equation 1-1. EQUATION 1-1: TCOUTPUT CALCULATION V OUT  MAX  – V OUT  MIN 
6
TC OUT = ------------------- 10 ppm/ C
 T  V OUT  NOM  Where:
VOUT(MAX) = Maximum output voltage over the
temperature range
VOUT(MIN) = Minimum output voltage over the
temperature range
VOUT(NOM) = Average output voltage over the
temperature range
T = Temperature range over which the
data was collected 1.1.4 DROPOUT VOLTAGE The dropout voltage is defined as the voltage difference
between VDD and VOUT under load. Equation 1-2 is
used to calculate the dropout voltage. EQUATION 1-2:
V DO = V IN – V OUT | I OUT = Cons tan t 1.1.5 EQUATION 1-3:
 V OUT
----- 100% = % Line Regulation
 V IN
Line regulation may also be expressed as %/V or in
ppm/V, as shown in Equation 1-4 and Equation 1-5,
respectively. EQUATION 1-4:
  V OUT 
 ---------
 V OUT  NOM 
%
----------- 100% = --Line Regulation
 V IN
V EQUATION 1-5:
  V OUT 
 ---------
 V OUT  NOM 
6
ppm
----------- 10 = ---Line Regulation
 V IN
V
As an example, if the MCP1501-20 is implemented in a
design and a 2 µV change in output voltage is measured from a 250 mV change on the input, then the
error in percent, ppm, percent/volt, and ppm/volt, as
shown in Equation 1-6 – Equation 1-9. EQUATION 1-6:
  V OUT

2 V
 ----- 100%   ----- 100% = .0008%

V
250 mV


IN EQUATION 1-7:
  V OUT
6
6
2 V
 ----- 10    ----- 10  = 8 ppm
250 mV
  V IN
 EQUATION 1-8:
2  V - 
  ----  2.048V 
----- 100% =  ------  100% = 0.000390625 %
- V IN
V
 250 mV 

  V OUT LINE REGULATION An ideal voltage reference will maintain a constant output voltage regardless of any changes to the input voltage. However, when real devices are considered, a
small error may be measured on the output when an
input voltage change occurs. EQUATION 1-9:
2  V - 
  ---- V OUT
  2.048V 
6
6
ppm
----- 10 =  ------  10 = 3.90625 --- V IN
V
 250 mV 

 Line regulation is defined as the change in output voltage (VOUT) as a function of a change in input voltage
(VIN), and expressed as a percentage, as shown in
Equation 1-3.  2015-2017 Microchip Technology Inc. DS20005474E-page 5