TLE4470GS datasheet(14/22 Pages) SIEMENS

14 / 22 page

TLE 4470

Semiconductor Group

1998-11-01

Input, Output

The input capacitor

I is necessary for compensating line influences. Using a resistor of

approx. 1

Ω in series with C

I, the LC circuit of input inductivity and input capacitance can

be damped. To stabilize the regulation circuits of the stand-by and main regulator, output

capacitors

Q1 and CQ2 are necessary. Stability is guaranteed at values CQ1 ≥ 6 µF &

Q2 ≥ 10 µF, both with an ESR ≤ 10 Ω within the operating temperature range.

For the TLE 4470 G (P-DSO-20-6) the output voltage

Q2 of the main regulator can be

adjusted to 5 V

≤ V

Q2rated ≤ 20 V by connecting an external voltage divider to the voltage

adjust pin VA. For

Q2 = 5 V the voltage adjust pin has to be connected directly to the

main output.

For calculating

Q or R1 & R2 respectively the following equations can be used:

Q = Vref × (R1 + R2) / R2

1 = R × (VQ / Vref)

2 = R × R1 / (R1 – R)

Definitions:

1 // R2 ;

≈ 100 kΩ

ref = Output voltage of stand by regulator, typical 5 V

Disable

The main regulator of the TLE 4470 can be switched OFF by a voltage of 2.3 V at pin

DIS. Reducing this voltage below 1.4 V will switch ON the main regulator again.

Reset Timing

The power-on reset delay time is defined by the charging time of an external capacitor

d which can be calculated as follows:

d = (∆td × Id) / ∆V

Definitions:

= delay capacitor

∆t

d = delay time

= charge current, typical 5

µA

∆V= V

dt, typical 1.8 V

dt = upper delay switching threshold at Cd for reset delay time

The reset reaction time

rr is the time it takes the voltage regulator to set the reset out

LOW after the output voltage has dropped below the reset threshold. It is typically 2

µs

for delay capacitor of 100 nF. For other values for

d the reaction time can be estimated

using the following equation:

rr ≈ 20 s/F × Cd

TLE4470GS датащи(PDF) 14 Page - Siemens Semiconductor Group

TLE4470GS датащи(HTML) 14 Page - Siemens Semiconductor Group

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

датащи скачать

ссылки URL