SBVS099H november 2007 – april 2023 TPS74701
PRODUCTION DATA
The TPS74701 offers very low dropout performance, making the device designed for high-current, low VIN and low VOUT applications. The low dropout of the TPS74701 allows the device to be used in place of a DC/DC converter and still achieve good efficiency. This feature provides designers with the power architecture for applications to achieve the smallest, simplest, and lowest cost solution.
There are two different specifications for dropout voltage with the TPS74701. The first specification (shown in Figure 8-1) is referred to as VIN dropout and is used when an external bias voltage is applied to achieve low dropout. This specification assumes that VBIAS is at least 1.39 V#SBVS0996181 above VOUT, which is the case for VBIAS when powered by a 3.3-V rail with 5% tolerance and with VOUT = 1.5 V. If VBIAS is higher than VOUT +1.39 V#SBVS0996181, VIN dropout is less than specified.(1)
The second specification (shown in Figure 8-2) is referred to as VBIAS dropout and applies to applications where IN and BIAS are tied together. This option allows the device to be used in applications where an auxiliary bias voltage is not available or low dropout is not required. Dropout is limited by BIAS in these applications because VBIAS provides the gate drive to the pass transistor; therefore, VBIAS must be 1.39 V above VOUT. Because of this usage, IN and BIAS tied together easily consume a huge amount of power. Pay attention not to exceed the power rating of the device package.