Features
- Wide input voltage range of 3V to 40V
- Synchronous operation for high efficiency
- Integrated high-side and low-side NMOS devices
- Selectable PFM or PWM mode at light loads
- Internal fixed frequency (500kHz) or adjustable switching frequency (300kHz to 2MHz)
- Continuous output current up to 1.1A
- Internal or external soft-start
- Power-good and enable functions
- 500mA low dropout linear regulator
- 1.8V to 6V input
- ±1.8% VOUT accuracy ensured over line, load, and TJ = -40°C to +125°C
- Very low 45mV dropout voltage at VOUT = 2.5V
- Excellent PSRR over wide frequency range
- Programmable output soft-start time
- Very fast transient response
- Current limit protection
Description
The RAA212421 is a dual-output regulator combining a 3V to 40V input, 1.1A synchronous buck converter with a 500mA LDO featuring fast transient response. The combination of two high-performance power supplies in one compact 3mm x 6mm package provide an easy-to-use, high-efficiency compact solution. The wide VIN buck regulator of the RAA212421 integrates both high-side and low-side nMOSFETs and features a PFM mode for improved efficiency at light load. This feature can be disabled if forced PWM mode is desired. It can use internal or external compensation, which minimizes the required external components, reduces BOM count and complexity of design. The part switches at a default frequency of 500kHz; however, it can also be programmed using an external resistor from 300kHz to 2MHz. Other features include programmable soft-start, hiccup mode overcurrent protection, thermal shutdown, and power-good. The LDO also features state-of-the-art internal compensation that allows it to achieve very fast load transient response. The device provides an output accuracy of ±1.8% VOUT accuracy over all load, line, and temperature variations (TJ = -40°C to +125°C). Other features include soft-start and enable that allow the LDO to be placed into low quiescent current shutdown mode. The part is available in a small Pb-free 3mm x 6mm DFN plastic package with a full-range industrial temperature of -40°C to +125°C.
Parameters
| Attributes | Value |
|---|---|
| Topology [Rail 1] | Buck |
| Outputs (#) | 2 |
| Input Voltage (Min) [Rail 1] (V) | 1.8 |
| Input Voltage (Max) [Rail 1] | 6 |
| Output Voltage (Min) [Rail 1] (V) | 0.5 |
| Output Voltage (Max) [Rail 1] (V) | 5.5 |
| Output Current (Max) [Rail 1] (A) | 0.5 |
| Switching Frequency Range (Typical) (kHz) | 300 - 2000 |
| Control Type | Current Mode |
| Peak Efficiency (%) | 94 |
| IQ [Rail 1] (µA) | 2200 |
| SYNCH Capability | Yes |
| Qualification Level | Standard |
| Temp. Range (°C) | -40 to +125°C |
Package Options
| Pkg. Type | Pkg. Dimensions (mm) | Lead Count (#) | Pitch (mm) |
|---|---|---|---|
| TDFN | 6.0 x 3.0 x 0.75 | 22 | 0.5 |
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