The TPS7B4256-Q1 is a monolithic, integrated, low-dropout (LDO) voltage tracker. The device is available in 8-pin SOIC and HSOIC packages. The TPS7B4256-Q1 is designed to provide power supply to off-board sensors in an automotive environment. Because the risk of failure in cables that deliver off-board power is high, the device comes with integrated protection features against fault conditions such as short to battery, reverse polarity, output short to ground (current limit), and overtemperature (thermal shutdown). The device incorporates a back-to-back PMOS topology that eliminates the need for an external diode that is otherwise required to help protect against fault conditions that result in flow of reverse current. The device is designed to handle a 45-V (absolute maximum) input voltage and survive the automotive load dump transient conditions.
A reference voltage applied at the adjustable input pin (ADJ/EN) is tracked with a very tight 6 mV (max) tolerance at the FB pin across temperature. This tracking enables the TPS7B4256-Q1 to deliver a power-supply voltage with high precision for loads up to 70 mA. The reference voltage can be directly connected to the ADJ/EN pin or scaled down to lower values with the help of an external resistor divider at the ADJ/EN pin to a minimum of 2 V. The output voltage can be made equal to the voltage at the ADJ/EN pin (± the tracking tolerance) by tying the FB pin directly to the OUT pin or scaled to higher values with the help of a resistive voltage divider between the FB and the OUT pin.
PART NUMBER | PACKAGE(1) | PACKAGE SIZE(2) |
---|---|---|
TPS7B4256-Q1 | DDA (HSOIC, 8) | 4.9 mm × 6 mm |
D (SOIC, 8) |
The TPS7B4256-Q1 provides an effective buffer to the reference voltage of an ADC and securely transmits this voltage (or a scaled version thereof) over a long cable to power off-board sensors. If the sensor is ratiometric and the output is sampled by the ADC, the described features of the TPS7B4256-Q1 help significantly improve the reliability and accuracy of the sensor measurements.
By setting the ADJ/EN input pin low, the TPS7B4256-Q1 switches to standby mode and reduces the quiescent current consumption of the LDO to less than 3.5 μA.
PIN | TYPE | DESCRIPTION | ||
---|---|---|---|---|
NAME | D | DDA | ||
ADJ/EN | 5 | 5 | I | Adjustable/enable input pin. Connect the external reference voltage to this pin. This pin connects to the inverting input of the error amplifier internally. A low signal below VIL disables the device, and a high signal above VIH enables the device. Connect the voltage reference directly, or with a voltage divider to attain output voltages lower than the reference; see the Tracker Output Voltage (VOUT) section for more details. To compensate for line influences, place a 0.1-μF capacitor close to this pin. |
FB | 4 | 4 | I | Feedback pin. This pin is connected to the noninverting input of the error amplifier internally and can be used to control the output voltage. For output voltages equal to or less than the external reference voltage, connect this pin directly to the output pin. To attain output voltage values higher than the reference, use a voltage divider with external feedback resistors; see the Tracker Output Voltage (VOUT) section for more details. |
GND | 2, 3, 6, 7 | 6 | G | GND pin. Connect this pin to a low impedance path to ground. |
IN | 8 | 8 | I | Input power-supply voltage pin. For best transient response and to minimize input impedance, use the recommended value or larger ceramic capacitor from IN to GND, as listed in the Recommended Operating Conditions table. Place the input capacitor as close to the input pin of the device as possible to compensate for line influences. |
NC | — | 2, 3, 7 | — | Not internally connected. For best thermal performance, connect these pins to GND. |
OUT | 1 | 1 | O | Regulated output voltage pin. A capacitor is required from OUT to GND for stability. For best transient response, use the nominal recommended value or larger ceramic capacitor from OUT to GND; see the Recommended Operating Conditions table. Place the output capacitor as close to output of the device as possible. |
Thermal Pad | — | Pad | Thermal pad. Connect the pad to GND for best possible thermal performance. |