LD39300XX25 STMicroelectronics, LD39300XX25 Datasheet - Page 11

• Manufacturer Part Number: LD39300XX25
• Description: Ultra low drop BICMOS voltage regulator
• Manufacturer: STMicroelectronics

Specifications of LD39300XX25

• Fixed And Adj Output Voltages: 1.22V, 1.8V, 2.5V, 3.3V, ADJ. (*see order code)
• Temperature Range: -40 to 125°C

LD39300
7
7.1
7.2
7.3
7.4
7.5
Application notes
External capacitors
The LD39300 requires external capacitors for regulator stability. These capacitors must be
selected to meet the requirements of minimum capacitance and equivalent series resistance
(see
the relative pins and connected directly to the input/output ground pins using traces which
have no other currents flowing through them. Any good quality of Ceramic or Electrolytic
capacitors can be used.
Input capacitor
An input capacitor whose minimum value is 1µF is required with the LD39300 (amount of
capacitance can be increased without limit). This capacitor must be located a distance of not
more than 1cm from the input pin of the device and returned to a clean analog ground. Any
good quality ceramic, tantalum or film capacitors can be used for this capacitor.
Output capacitor
It is possible to use Ceramic or Tantalum capacitors but the output capacitor must meet the
requirement for minimum amount of capacitance and E.S.R. (equivalent series resistance)
value. A minimum capacitance of 4.7µF is a good choice to guarantee the stability of the
regulator. Anyway, other C
showing the allowable ESR range as a function of the output capacitance. This curve
represents the stability region over the full temperature and I
Thermal note
The output capacitor must maintain its ESR in the stable region over the full operating
temperature range to assure stability. Also, capacitors tolerance and variation with
temperature must be kept in consideration in order to assure the minimum amount of
capacitance at all times.
Inhibit input operation
The inhibit pin can be used to turn OFF the regulator when pulled down, so drastically
reducing the current consumption down to less than 1µA. When the inhibit feature is not
used, this pin must be tied to V
proper operation, the signal source used to drive the inhibit pin must be able to swing above
and below the specified thresholds listed in the electrical characteristics section (V
The inhibit pin must not be left floating because it is not internally pulled down/up.
Figure 14. Figure 15.
). The input/output capacitors must be located less than 1cm from
O
values can be used according to the (
I
to keep the regulator output ON at all times. To assure
O
range.
Figure 14. Figure 15.
Application notes
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