1996 Mar 20
3
Philips Semiconductors
Product specication
Voltage reference diodes
1N821 to 1N829
1N821A to 1N829A
ELECTRICAL CHARACTERISTICS
Tj = 25 °C unless otherwise specied.
Notes
1. The quoted values of
V
ref are based on a constant current IZ. Two factors can cause Vref to change, namely the
differential resistance rdif and the temperature coefficient SZ.
a) As the max. rdif of the device can be 15 , a change of 0.01 mA in the current through the reference diode will
result in a
Vref of 0.01 mA × 15 = 0.15 mV. This level of Vref is not significant on a 1N821 (Vref < 96 mV),
it is however very significant on a 1N829 (
Vref < 5 mV).
b) The temperature coefficient of the reference voltage SZ is a function of IZ. Reference diodes are classified at the
specified test current and the SZ of the reference diode will be different at different levels of IZ. The absolute value
of IZ is important, however, the stability of IZ, once the level has been set, is far more significant. This applies
particularly to the 1N829. The effect of the stability of IZ on SZ is shown in Fig.3.
2. All reference diodes are characterized by the ‘box method’. This guarantees a maximum voltage excursion (
Vref)
over the specified temperature range, at the specified test current (IZ), verified by tests at indicated temperature
points within the range. VZ is measured and recorded at each temperature specified. The Vref between the highest
and lowest values must not exceed the maximum
V
ref given. Therefore the temperature coefficient is only given as
a reference. It may be derived from:
THERMAL CHARACTERISTICS
SYMBOL
PARAMETER
CONDITIONS
MIN.
TYP.
MAX.
UNIT
Vref
reference voltage
IZ =7.5 mA
5.89
6.20
6.51
V
ref
reference voltage excursion
IZ =7.5 mA; test points for
Tamb: 55; +25; +75; +100 °C;
see Fig.2; notes 1 and 2
1N821; 1N821A
96
mV
1N823; 1N823A
48
mV
1N825; 1N825A
19
mV
1N827; 1N827A
9mV
1N829; 1N829A
5mV
S
Z
temperature coefcient
IZ = 7.5 mA: see Fig.3;
notes 1 and 2
1N821; 1N821A
0.01
%/K
1N823; 1N823A
0.005
%/K
1N825; 1N825A
0.002
%/K
1N827; 1N827A
0.001
%/K
1N829; 1N829A
0.0005 %/K
rdif
differential resistance
IZ = 7.5 mA; see Fig.4
1N821 to 1N829
15
1N821A to 1N829A
10
SYMBOL
PARAMETER
CONDITIONS
VALUE
UNIT
Rth j-tp
thermal resistance from junction to tie-point
8 mm from the body
300
K/W
Rth j-a
thermal resistance from junction to ambient
lead length 10 mm
375
K/W
S
Z
V
ref1
V
ref2
–
T
amb2
T
amb1
–
--------------------------------------
100
V
ref nom
-------------------- %/K
×
=