Datasheet

TPS7A3001
OUT
FB
GND
C
10 F
IN
m
C
10nF
NR/SS
R
1
R
2
C
10nF
BYP
C
10 F
OUT
m
IN
EN
NR/SS
V
IN
V
OUT
V
OUT
V
REF
- 1 R =R
1 2
V
OUT
R +R
1 2
³ 5 Am,where
Time(20ms/div)
V
IN
V
EN
V
OUT
TPS7A3001-EP
www.ti.com SBVS174 –OCTOBER 2011
THEORY OF OPERATION
GENERAL DESCRIPTION
The TPS7A3001 belongs to a family of new generation linear regulators that use an innovative bipolar process to
achieve ultralow-noise and very high PSRR levels at a wide input voltage range. These features, combined with
a high thermal performance MSOP-8 with PowerPAD package make this device ideal for high-performance
analog applications.
ADJUSTABLE OPERATION
The TPS7A3001 has an output voltage range of –1.174 to –35V. The nominal output voltage of the device is set
by two external resistors, as shown in Figure 30.
Figure 30. Adjustable Operation for Maximum AC Performance
R
1
and R
2
can be calculated for any output voltage range using the formula shown in Equation 1. To ensure
stability under no load conditions, this resistive network must provide a current equal to or greater than 5μA.
(1)
If greater voltage accuracy is required, take into account the output voltage offset contributions because of the
feedback pin current and use 0.1% tolerance resistors.
ENABLE PIN OPERATION
The TPS7A3001 provides a dual polarity enable pin (EN) that turns on the regulator when |V
EN
| > 2.0V, whether
the voltage is positive or negative, as shown in Figure 31.
This functionality allows for different system power management topologies:
• Connecting the EN pin directly to a negative voltage, such as V
IN
, or
• Connecting the EN pin directly to a positive voltage, such as the output of digital logic circuitry.
Figure 31. Enable Pin Positive/Negative Threshold
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