1N821 datasheet(3/5 Pages) PHILIPS

3 / 5 page

1996 Mar 20

Philips Semiconductors

Product speciﬁcation

Voltage reference diodes

1N821 to 1N829

1N821A to 1N829A

ELECTRICAL CHARACTERISTICS

Tj = 25 °C unless otherwise speciﬁed.

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 Ω, a change of 0.01 mA in the current through the reference diode will

result in a

∆Vref of 0.01 mA × 15 Ω = 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

−−

1N823; 1N823A

−−

1N825; 1N825A

−−

1N827; 1N827A

−−

9mV

1N829; 1N829A

−−

5mV

S

Z

temperature coefﬁcient

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

−−

Ω

1N821A to 1N829A

−−

Ω

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

ref1

ref2

–

amb2

amb1

–

--------------------------------------

100

ref nom

-------------------- %/K

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