Rainbow Electronics 78M6631 - Manual (Page 19)

DS_6631_056 78M6631 Data Sheet
Rev 1 19
2.4.7 Temperature Sensor
Table 11 shows the performance for the temperature sensor. The LSB values do not include the 8-bit left
shift at CE input.
Table 11: Temperature Sensor Performance Specifications
Parameter Condition Min Typ Max Unit
Nominal relationship: N(T) = S
n
*(T-T
n
) + N
n
, T
n
= 22ºC
Nominal
Sensitivity (S
n
)
3
n 3
L
00107 . 0 S 





⋅ − =
[M26MHZ, M40MH] =
[00], [01], or [11]
FIR_LEN= 0 (L=138)
FIR_LEN=1 (L=288)
-104
-947
LSB/ºC
[M26MHZ, M40MHZ] =
[10]
FIR_LEN=0 (L=186) -255
Nominal Offset
(N
n
) 4
3
n
3
L
510 . 0 N 





⋅ =
[M26MHZ, M40MH] =
[00], [01], or [11]
FIR_LEN=0 (L=138)
FIR_LEN=1 (L=288)
49641
451200
LSB
[M26MHZ, M40MHZ] =
[10]
FIR_LEN=0 (L=186)
121500
Temperature Error 2






+
−
− =
n
n
n T
S
N T N
T ERR
) ) ( (
T
n
= 22°C,
T = -40ºC to +85ºC
-10 1 +10 1 ºC
1 Guaranteed by design; not production tested.
2 N
n
is measured at T
n
during measurement calibration and is stored in MPU or CE for use in temperature
calculations.
2.4.8 VREF
Table 12 shows the performance specifications for VREF. Unless otherwise specified, VREF_DIS = 0.
Table 12: VREF Performance Specifications
Parameter Condition Min Typ Max Unit
VREF output voltage, VREF(22) T
A
= +22ºC 1.193 1.195 1.197 V
VREF chop step 40 mV
VREF power supply sensitivity
ΔVREF/ΔV3P3A V3P3A = 3.0 to 3.6 V
-1.5 +1.5 mV/V
VREF input impedance VREF_DIS = 1,
VREF = 1.3 to 1.7 V
100 kΩ
VREF output impedance CAL =1,
I
LOAD = 10 µA, -10 µA
2.5 kΩ
VNOM definition 2 2 ) 22 ( 1 ) 22 ( ) 22 ( ) ( 2 TC T TC T VREF T VNOM − + − + = V
VNOM temperature coefficients:
TC1
TC2
3.18·(52.46-TRIMT)
-0.444
µ V/ºC
µ V/°C 2
VREF(T) deviation from VNOM(T)
) 40 , 22 max(
10
) (
) ( ) ( 6
−
−
T T VNOM
T VNOM T VREF -40 1 +40 1 ppm/ºC
VREF aging ± 25 ppm/year
1 Guaranteed by design; not production tested.
2 This relationship describes the nominal behavior of VREF at different temperatures.