LMR120xx 20-VIN, 1.5-A or 2-A Step-Down Voltage Regulator in WSON Package
1 Features
- Input Voltage Range of 3 V to 20 V
- Output Voltage Range of 1 V to 18 V
- LMR12015 and LMR12020 Deliver 1.5-A and 2-A Maximum Output Current, Respectively
- 2-MHz Switching Frequency
- Frequency Synchronization from 1 MHz to 2.35 MHz
- 70-nA Shutdown Current
- 1% Voltage-Reference Accuracy
- Peak-Current-Mode PWM Operation
- Thermal Shutdown
- Internally Compensated
- Internal Soft Start
- Tight Accuracy for Powering Digital ICs
- Extremely Easy to Use
- Tiny Overall Solution Reduces System Cost
- Space-Saving WSON (3 × 3 × 0.8 mm) Packaging
- Create a custom design using the LMR12015 WEBENCH® Power Designer or LMR12020 WEBENCH® Power Designer
2 Applications
- Point-of-Load Conversions from 3.3-V, 5-V, and 12-V Rails
- Space-Constrained Applications
3 Description
The LMR120xx regulator is a monolithic, high frequency, PWM step-down DC/DC converter in a 10-pin WSON package. It contains all the active functions to provide local DC/DC conversion with fast transient response and accurate regulation in the smallest possible PCB area.
With a minimum of external components the LMR12015/20 is easy to use. The ability to drive 1.5-A or 2-A loads, with an internal 150-mΩ NMOS switch results in the best power density available. The control circuitry allows for on-times as low as 65 ns, thus supporting exceptionally high frequency conversion. Switching frequency is internally set to 2 MHz and synchronizable from 1 to 2.35 MHz, which allows the use of extremely small surface mount inductors and chip capacitors. Even though the operating frequency is very high, efficiencies up to 90% are easy to achieve. External shutdown is included featuring an ultra-low shutdown current of 70 nA. The LMR12015/20 utilizes peak current mode control and internal compensation to provide high-performance regulation over a wide range of operating conditions. Additional features include internal soft-start circuitry to reduce inrush current, pulse-by-pulse current limit, thermal shutdown, and output overvoltage protection.
Device Information(1)
| PART NUMBER | PACKAGE | BODY SIZE (NOM) |
|---|---|---|
| LMR12015 | WSON (10) | 3.00 mm × 3.00 mm |
| LMR12020 |
- For all available packages, see the orderable addendum at the end of the data sheet.
Device Images
Typical Application Circuit
5 Pin Configuration and Functions
Pin Descriptions
| PIN | DESCRIPTION | |
|---|---|---|
| NO. | NAME | |
| 1,2 | SW | Output switch. Connects to the inductor, catch diode, and bootstrap capacitor. |
| 3 | BOOST | Boost voltage that drives the internal NMOS control switch. A bootstrap capacitor is connected between the BOOST and SW pins. |
| 4 | EN | Enable control input. Logic high enables operation. Do not allow this pin to float or be greater than VIN + 0.3 V. |
| 5 | SYNC | Frequency synchronization input. Drive this pin with an external clock or pulse train. Ground it to use the internal clock. |
| 6 | FB | Feedback pin. Connect FB to the external resistor divider to set output voltage. |
| 7 | GND | Signal and Power Ground pin. Place the bottom resistor of the feedback network as close as possible to this pin for accurate regulation. |
| 8 | AVIN | Supply voltage for the control circuitry. |
| 9,10 | PVIN | Supply voltage for output power stage. Connect a bypass capacitor to this pin. |
| DAP | GND | Signal / Power Ground and thermal connection. Tie this directly to GND (pin 7). See regarding optimum thermal layout. |
