TPS7A39 Dual, 150-mA, Wide VIN Positive and Negative LDO Voltage Regulator
1 Features
- Positive and Negative LDOs in One Package
- Wide Input Voltage Range: ±3.3 V to ±33 V
- Wide Output Voltage Range:
- Positive Range: 1.2 V to 30 V
- Negative Range: –30 V to 0 V
- Output Current: 150 mA per Channel
- Monotonic Start-Up Tracking
- High Power-Supply Rejection Ratio (PSRR):
- 69 dB (120 Hz)
- ≥ 50 dB (10 Hz to 2 MHz)
- Output Voltage Noise: 21 µVRMS (10 Hz–100 kHz)
- Buffered 1.2-V Reference Output
- Stable With a 10-µF or Larger Output Capacitor
- Single Positive-Logic Enable
- Adjustable Soft-Start In-Rush Control
- 3-mm × 3-mm, 10-Pin WSON Package
- Low Thermal Resistance: RθJA = 44.4°C/W
- Operating Temperature Range: –40 to +125°C
2 Applications
- Supply Rails for Op Amps, ADCs, DACs, and Other High-Precision Analog Circuitry
- Post DC-DC Regulation and Filtering
- Analog I/O Modules
- Test and Measurement
- Rx, Tx, and PA Circuitry
- Industrial Instrumentation
- Medical Imaging
3 Description
The TPS7A39 device is a dual, monolithic, high-PSRR, positive and negative low-dropout (LDO) voltage regulator capable of sourcing (and sinking) up to 150 mA of current. The regulated outputs can be independently and externally adjusted to symmetrical or asymmetrical voltages, making this device an ideal dual, bipolar power supply for signal conditioning.
Both positive and negative outputs of the TPS7A39 ratiometrically track each other during startup to mitigate floating conditions and other power-supply sequencing issues common in dual-rail systems. The negative output can regulate up to 0 V, extending the common-mode range for single-supply amplifiers. The TPS7A39 also features high PSRR to eliminate power-supply noise, such as switching noise, that can compromise signal integrity.
Both regulators are controlled with a single positive logic enable pin for interfacing with standard digital logic. A capacitor-programmable soft-start function controls in-rush current and start-up time. The internal reference voltage of the TPS7A39 can be overridden with an external reference to enable precision outputs, output voltage margining, or to track other power supplies. Additionally, the TPS7A39 has a buffered reference output that can be used as a voltage reference for other components in the system.
These features make the TPS7A39 a robust, simplified solution to power operational amplifiers, digital-to-analog converters (DACs), and other precision analog circuitry.
Device Information(1)
| PART NUMBER | PACKAGE | BODY SIZE (NOM) |
|---|---|---|
| TPS7A39 | WSON (10) | 3.00 mm × 3.00 mm |
- For all available packages, see the orderable addendum at the end of the data sheet.
Powering the Signal Chain
Monotonic Start-Up Tracking
5 Pin Configuration and Functions
Pin Functions
| PIN | I/O | DESCRIPTION | |
|---|---|---|---|
| NO. | NAME | ||
| 1 | INP | I | Positive input. A 10-μF(1) or larger capacitor must be tied from this pin to ground to ensure stability. Place the input capacitor as close to the input as possible; see the Capacitor Recommendations section for more information. |
| 2 | EN | I | Enable pin. Driving this pin to logic high (VEN ≥ VIH(EN)) enables the device; driving this pin to logic low (VEN ≤ VIL(EN)) disables the device. If enable functionality is not required, this pin must be connected to INP; see the Application and Implementation section for more detail. The enable voltage cannot exceed the input voltage (VEN ≤ VINP). |
| 3 | NR/SS | — | Noise-reduction, soft-start pin. Connecting an external capacitor between this pin and ground reduces reference voltage noise and enables soft-start and start-up tracking. A 10-nF or larger capacitor (CNR/SS) is recommended to be connected from NR/SS to GND to maximize or optimize ac performance and to ensure start-up tracking. This pin can also be driven externally to provide greater output voltage accuracy and lower noise, see the User-Settable Buffered Reference section for more information. |
| 4 | GND | — | Ground pin. This pin must be connected to ground and the thermal pad with a low-impedance connection. |
| 5 | INN | I | Negative input. A 10-μF(1) or larger capacitor must be tied from this pin to ground to ensure stability. Place the input capacitor as close to the input as possible; see the Capacitor Recommendations section for more information. |
| 6 | OUTN | O | Negative output. A 10-μF(1) or larger capacitor must be tied from this pin to ground to ensure stability. Place the output capacitor as close to the output as possible; see the Capacitor Recommendations section for more information. |
| 7 | FBN | I | Negative output feedback pin. This pin is used to set the negative output voltage. Although not required, a 10-nF feed-forward capacitor from FBN to OUTN (as close to the device as possible) is recommended to maximize ac performance. Nominally this pin is regulated to VFBN. Do not connect to ground. |
| 8 | BUF | O | Buffered reference output. This pin is connected to FBN through R2 and the voltage at this node is inverted and scaled up by the negative feedback network to provide the desired output voltage. The buffered reference can be used to drive external circuits, and has a 1-mA maximum load. |
| 9 | FBP | I | Positive output feedback pin. This pin is used to set the positive output voltage. Although not required, a 10-nF feed-forward capacitor from FBP to OUTP (as close to the device as possible) is recommended to maximize ac performance. Nominally this pin is regulated to VFBP. Do not connect this pin directly to ground. |
| 10 | OUTP | O | Positive output. A 10-μF(1) or larger capacitor must be tied from this pin to ground to ensure stability. Place the output capacitor as close to the output as possible; see the Capacitor Recommendations section for more information. |
| Pad | Thermal Pad | — | Connect the thermal pad to a large-area ground plane. The thermal pad is internally connected to GND. |
