TDA3664_7 © NXP B.V. 2007. All rights reserved.
Product data sheet Rev. 07 — 25 June 2007 7 of 16
NXP Semiconductors
TDA3664
Very low dropout voltage/quiescent current 5 V voltage regulator
Remark: In the event of using different types of capacitors, a minimum ESR needs to
be created by using an additional resistor that is placed in series with the output
capacitor, see Figure 4.
• It is recommended not to use below 1 mA output current because of reduced phase
margin.
11.3 Application circuits
The maximum output current of the regulator equals:
When T
amb
=21°C, the maximum output current equals 140 mA at V
P
=14 V.
The total thermal resistance of the TDA3664 (SOT223-1 package) can be decreased to
lower values when pin 4 and body of the package are soldered to the printed-circuit board.
11.3.1 Application circuit with backup function
Sometimes, a backup function is needed to supply, for example, a microcontroller for a
short period of time when the supply voltage spikes to 0 V (or even −1 V).
This function can easily be built with the TDA3664 by using a large output capacitor. When
the supply voltage is 0 V (or −1 V), only a small current will flow into pin REG from this
large output capacitor (a few µA).
The application circuit is given in Figure 4.
Table 8: Minimum ESR values required
I
REG
(mA) max C2 = 100 nF C2=1µF C2=10µF C2 = 100 µF
1>0Ω > 1.5 Ω > 2.5 Ω >0Ω
5>1Ω > 0.5 Ω >1Ω >0Ω
10 > 0 Ω > 0.5 Ω >4Ω >0Ω
100 > 0 Ω > 0.5 Ω >4Ω >0Ω
I
REG max()
150 T
amb
–
R
th j a–()
V
P
V
REG
–()×
----------------------------------------------------------
150 T
amb
–
100 V
P
5–()×
------------------------------------
mA()==
(1) C1 is optional (to minimize supply noise only)
(2) C2 ≤ 4700 µF
(3) V
REG
=5V
(4) For reliable operation, it is recommended to have a minimum ESR of 3 Ω of the output
capacitor total (see Figure 4 above) and to have a stable application independent of load
current, temperature or output capacitance.
Fig 4. Application circuit with backup function (SO4 version)
014aaa089
V
P
13
2, 4
V
REG
(3)
C1
(1)
1
µF
C2
(2)
TDA3664
