AMS1117-2.85

Part: AMS1117 series by Advanced Monolithic Systems

Type: Low Dropout Voltage Regulator

Description: The AMS1117 series are adjustable and fixed voltage regulators designed to provide up to 1A output current and operate down to 1V input-to-output differential, available in 1.5V, 1.8V, 2.5V, 2.85V, 3.3V, and 5.0V fixed output options.

Operating Conditions:

• Supply voltage: VOUT + 1V to 15V (max input voltage 15V, 1V dropout)
• Operating temperature: -40 to 125 °C (Junction)
• Max output current: 1A

Absolute Maximum Ratings:

• Max supply voltage: 15V
• Max continuous current: 1A (Output Current)
• Max junction/storage temperature: +150 °C (Storage)

Key Specs:

• Dropout Voltage: 1.3V max (at IOUT = 0.8A)
• Reference Voltage (AMS1117): 1.232V min, 1.250V typ, 1.268V max (IOUT = 10mA, 1.5V ≤ (VIN - VOUT) ≤ 12V)
• Line Regulation (AMS1117): 0.2% max (1.5V ≤ (VIN - VOUT) ≤ 12V)
• Load Regulation (AMS1117): 0.4% max ((VIN - VOUT) = 1.5V, 10mA ≤ IOUT ≤ 0.8A)
• Current Limit: 900 mA min, 1500 mA max ((VIN - VOUT) = 1.5V)
• Quiescent Current: 5 mA typ, 11 mA max ((VIN - VOUT) = 1.5V)
• Ripple Rejection (AMS1117): 60 dB min (f = 120Hz, C OUT = 22 μF Tantalum, I OUT = 1A, (V IN -V OUT ) = 3V, C ADJ =10 μF)
• Thermal Resistance Junction-to-Case: 15 °C/W max (All packages)

Features:

• Three Terminal Adjustable or Fixed Voltages: 1.5V, 1.8V, 2.5V, 2.85V, 3.3V and 5.0V
• Output Current of 1A
• Operates Down to 1V Dropout
• Line Regulation: 0.2% Max.
• Load Regulation: 0.4% Max.
• SOT-223, TO-252 and SO-8 package available

Applications:

• High Efficiency Linear Regulators
• Post Regulators for Switching Supplies
• 5V to 3.3V Linear Regulator
• Battery Chargers
• Active SCSI Terminators
• Power Management for Notebook
• Battery Powered Instrumentation

Package:

• TO-252
• SOT-223
• 8L SOIC

• Three Terminal Adjustable or Fixed Voltages* 1.5V, 1.8V, 2.5V, 2.85V, 3.3V and 5.0V
• Output Current of 1A
• Operates Down to 1V Dropout
• Line Regulation: 0.2% Max.
• Load Regulation: 0.4% Max.
• SOT-223, TO-252 and SO-8 package available

• High Efficiency Linear Regulators
• Post Regulators for Switching Supplies
• 5V to 3.3V Linear Regulator
• Battery Chargers
• Active SCSI Terminators
• Power Management for Notebook
• Battery Powered Instrumentation

SOT-223 Top View

AMS1117

1A LOW DROPOUT VOLTAGE REGULATOR

RoHs Compliant

8L SOIC Top View

1

2 V OUT

8

4

3 V OUT

7

5

6

V OUT

N/C

V OUT

GND/ADJ

N/C

V IN

TO-252 FRONT VIEW

Electrical Characteristics at IOUT = 0 mA, and TJ = +25°C unless otherwise specified.

Soldering information

Lead Temperature (25 sec)

265 ° C

Thermal Resistance

SO-8 package

ϕ JA= 160 ° C/W

TO-252 package

ϕ JA= 80 ° C/W

SOT-223 package

ϕ JA= 90 ° C/W*

• With package soldering to copper area over backside ground plane or internal power plane ϕ JA can vary from 46 ° C/W to > 90 ° C/W depending on mounting technique and the size of the copper area.

(Note 1)

Power Dissipation

Internally limited

Input Voltage

15V

Operating Junction Temperature Range

Control Section

-40 ° C to 125 ° C

Power Transistor

-40 ° C to 125 ° C

Storage temperature

• 65 ° C to +150 ° C

The AMS1117 series have internal power and thermal limiting circuitry designed to protect the device under overload conditions. However maximum junction temperature ratings of 125 ° C should not be exceeded under continuous normal load conditions.

Careful consideration must be given to all sources of thermal resistance from junction to ambient. For the surface mount package SOT-223 additional heat sources mounted near the device must be considered. The heat dissipation capability of the PC board and its copper traces is used as a heat sink for the device. The thermal resistance from the junction to the tab for the AMS1117 is 15 ° C/W. Thermal resistance from tab to ambient can be as low as 30 ° C/W.

Table 1.

The total thermal resistance from junction to ambient can be as low as 45 ° C/W. This requires a reasonable sized PC board with at least on layer of copper to spread the heat across the board and couple it into the surrounding air.

Experiments have shown that the heat spreading copper layer does not need to be electrically connected to the tab of the device. The PC material can be very effective at transmitting heat between the pad area, attached to the pad of the device, and a ground plane layer either inside or on the opposite side of the board. Although the actual thermal resistance of the PC material is high, the Length/Area ratio of the thermal resistance between layers is small. The data in Table 1, was taken using 1/16' FR-4 board with 1 oz. copper foil, and it can be used as a rough guideline for estimating thermal resistance.

For each application the thermal resistance will be affected by thermal interactions with other components on the board. To determine the actual value some experimentation will be necessary.

The power dissipation of the AMS1117 is equal to:

Maximum junction temperature will be equal to:

TJ = TA(MAX) + PD(Thermal Resistance (junction-to-ambient))

Maximum junction temperature must not exceed 125 ° C.

TO-252 PLASTIC PACKAGE (D)

3 LEAD SOT-223 PLASTIC PACKAGE

PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted (Continued).