LT1763

Part: LT1763 series — Linear Technology Corporation

Type: Micropower, Low Noise, Low Dropout Regulator

Description: The LT1763 series are micropower, low noise, low dropout regulators capable of supplying 500mA of output current with a dropout voltage of 300mV, featuring a wide input voltage range of 1.8V to 20V and low 30μA quiescent current.

Operating Conditions:

• Supply voltage: 1.8V to 20V
• Operating temperature: -40°C to 125°C (C, I Grade), -55°C to 125°C (MP Grade)
• Output current: 500mA

Absolute Maximum Ratings:

• Max supply voltage (IN Pin): ±20V
• Max continuous current: 500mA
• Max junction/storage temperature: 125°C (Operating Junction), 150°C (Storage)

Key Specs:

• Output Current: 500mA
• Low Quiescent Current: 30μA (I LOAD = 0mA)
• Low Dropout Voltage: 300mV (I LOAD = 500mA)
• Output Voltage Noise: 20μV RMS (C OUT = 10μF, C BYP = 0.01μF, I LOAD = 500mA, BW = 10Hz to 100kHz)
• Shutdown Current: 0.1μA (V IN = 6V, V SHDN = 0V)
• ADJ Pin Bias Current: 30 nA
• Current Limit: 520 mA (typ)
• Ripple Rejection: 65 dB (V IN - V OUT = 1.5V (Avg), V RIPPLE = 0.5V P-P, f RIPPLE = 120Hz, I LOAD = 500mA)

Features:

• Low Noise: 20μV RMS (10Hz to 100kHz)
• Low Quiescent Current: 30μA
• Wide Input Voltage Range: 1.8V to 20V
• Low Dropout Voltage: 300mV
• Very Low Shutdown Current: < 1μA
• Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 3V, 3.3V, 5V
• Adjustable Output from 1.22V to 20V
• Stable with 3.3μF Output Capacitor
• Reverse Battery Protection
• Overcurrent and Overtemperature Protected

Applications:

• Cellular Phones
• Battery-Powered Systems
• Noise-Sensitive Instrumentation Systems

Package:

• 8-Lead SO
• 12-Lead (4mm × 3mm × 0.75mm) DFN

• n Low Noise: 20μV RMS (10Hz to 100kHz)

• n Output Current: 500mA

• n Low Quiescent Current: 30μA

• n Wide Input Voltage Range: 1.8V to 20V

• n Low Dropout Voltage: 300mV

• n Very Low Shutdown Current: < 1μA

• n No Protection Diodes Needed

• n Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 3V, 3.3V, 5V

• n Adjustable Output from 1.22V to 20V

• n Stable with 3.3μF Output Capacitor

• n Stable with Aluminum, Tantalum or Ceramic Capacitors

• n Reverse Battery Protection

• n No Reverse Current

• n Overcurrent and Overtemperature Protected

• n 8-Lead SO and 12-Lead (4mm × 3mm) DFN Packages

• n Cellular Phones
• n Battery-Powered Systems
• n Noise-Sensitive Instrumentation Systems

temperature range, otherwise specifi cations are at T A = 25°C. (Note 2)

1763fg

IN Pin Voltage ........................................................ ±20V

OUT Pin Voltage ..................................................... ±20V

Input to Output Differential Voltage ........................ ±20V

SENSE Pin Voltage ............................................... ±20V

ADJ Pin Voltage ...................................................... ±7V

BYP Pin Voltage .....................................................±0.6V

SHDN Pin Voltage ................................................ ±20V

Output Short-Circuit Duration ........................ Indefi nite

Operating Junction Temperature Range (Note 2)

C, I Grade ...........................................- 40°C to 125°C

MP Grade ...........................................- 55°C to 125°C

Storage Temperature Range

S8 Package ........................................- 65°C to 150°C

DFN Package ......................................- 65°C to 150°C

Lead Temperature (Soldering, 10 sec)

S8 Package ....................................................... 300°C

The power handling capability of the device will be limited by the maximum rated junction temperature (125°C). The power dissipated by the device will be made up of two components:

1. Output current multiplied by the input/output voltage differential: (I OUT )(V IN - V OUT ), and
2. GND pin current multiplied by the input voltage: (I GND)(V IN ).

The GND pin current can be found by examining the GND Pin Current curves in the Typical Performance Characteristics section. Power dissipation will be equal to the sum of the two components listed above.

The LT1763 series regulators have internal thermal limiting designed to protect the device during overload conditions. For continuous normal conditions, the maximum junction temperature rating of 125°C must not be exceeded. It is important to give careful consideration to all sources of thermal resistance from junction-to-ambient. Additional heat sources mounted nearby must also be considered.

For surface mount devices, heat sinking is accomplished by using the heat spreading capabilities of the PC board and its copper traces. Copper board stiffeners and plated through-holes can also be used to spread the heat generated by power devices.

The following tables list thermal resistance for several different board sizes and copper areas. All measurements were taken in still air on 3/32" FR-4 board with one ounce copper.

Table 1. DE Package, 12-Lead DFN

Table 2. SO-8 Package, 8-Lead SO