TPS7A4533DCQT

Part: TPS7A45xx — Texas Instruments

Type: Low-Dropout Voltage Regulator

Description: 1.5 A low-noise, fast-transient-response LDO regulator operating up to 20 V with 300 mV dropout at full load.

Operating Conditions:

• Supply voltage: (VOUT + VDO) to 20 V
• Operating temperature: -40 to 125 °C (recommended junction temperature)

Absolute Maximum Ratings:

• Max supply voltage: 20 V (IN pin, -20 V to 20 V)
• Max junction/storage temperature: 150 °C (storage temperature: -65 to 150 °C)

Key Specs:

• Maximum output current: 1.5 A
• Dropout voltage: 300 mV (typ at ILOAD = 1.5 A, TJ = 25°C; 450 mV max over full range)
• Output voltage accuracy: 1% (at 25°C)
• Output noise voltage: 35 μVRMS (10 Hz to 100 kHz, COUT = 10 μF, ILOAD = 1.5 A, TJ = 25°C)
• Ripple rejection: 68 dB (f = 120 Hz, VIN - VOUT = 1.5 V avg, VRIPPLE = 0.5 VP-P, ILOAD = 0.75 A, TJ = 25°C)
• Quiescent current in shutdown: 0.01 μA typ, 1 μA max (VIN = 6 V, VSHDN = 0 V, TJ = 25°C)
• Ground pin current: 1 mA typ, 1.5 mA max (ILOAD = 0 mA, over full temperature range)
• Current limit: 1.6 A min (VIN = VOUT(NOMINAL) + 1 V, over full temperature range)

Features:

• Optimized for fast transient response
• Controlled quiescent current in dropout
• Stable with ceramic output capacitors as low as 10 μF
• Built-in reverse-battery, reverse-current, current-limit, and thermal-limiting protection
• No external protection diodes needed
• Precision enable/shutdown logic input

Applications:

• Industrial
• Wireless Infrastructure
• Radio-Frequency Systems

Package:

• 6-pin SOT-223 (DCQ)
• 5-pin TO-263 (KTT)

The TPS7A45xx regulators incorporate several protection features which make them ideal for use in batterypowered circuits. In addition to the normal protection features associated with monolithic regulators, such as current limiting and thermal limiting, the devices are protected against reverse input voltages, reverse output voltages and reverse voltages from output to input.

Current limit protection and thermal overload protection are intended to protect the device against current overload conditions at the output of the device. For normal operation, the junction temperature should not exceed 125°C.

The input of the device withstands reverse voltages of 20 V. Current flow into the device is limited to less than 1 mA (typically less than 100 μ A), and no negative voltage appears at the output. The device protects both itself and the load. This provides protection against batteries that can be plugged in backward.

The output of the TPS7A45xx can be pulled below ground without damaging the device. If the input is left open circuit or grounded, the output can be pulled below ground by 20 V. For fixed voltage versions, the output acts like a large resistor, typically 5 k Ω or higher, limiting current flow to typically less than 600 μ A. For adjustable versions, the output acts like an open circuit; no current flows out of the pin. If the input is powered by a voltage source, the output sources the short-circuit current of the device and protects itself by thermal limiting. In this case, grounding the SHDN pin turns off the device and stops the output from sourcing the short-circuit current.

The ADJ pin of the adjustable device can be pulled above or below ground by as much as 7 V without damaging the device. If the input is left open circuit or grounded, the ADJ pin acts like an open circuit when pulled below ground and like a large resistor (typically 5 k Ω ) in series with a diode when pulled above ground.

In situations where the ADJ pin is connected to a resistor divider that would pull the ADJ pin above its 7-V clamp voltage if the output is pulled high, the ADJ pin input current must be limited to less than 5 mA. For example, a resistor divider is used to provide a regulated 1.5-V output from the 1.21-V reference when the output is forced to 20 V. The top resistor of the resistor divider must be chosen to limit the current into the ADJ pin to less than 5 mA when the ADJ pin is at 7 V. The 13-V difference between OUT and ADJ divided by the 5-mA maximum current into the ADJ pin yields a minimum top resistor value of 2.6 k Ω .

SLVS720F -JUNE 2008-REVISED NOVEMBER 2015

In circuits where a backup battery is required, several different input/output conditions can occur. The output voltage may be held up while the input is either pulled to ground, pulled to some intermediate voltage, or is left open circuit.

When the IN pin of the TPS7A45xx is forced below the OUT pin or the OUT pin is pulled above the IN pin, input current typically drops to less than 2 μ A. This can happen if the input of the device is connected to a discharged (low voltage) battery and the output is held up by either a backup battery or a second regulator circuit. The state of the SHDN pin has no effect on the reverse output current when the output is pulled above the input.

• Industrial
• Wireless Infrastructure
• Radio-Frequency Systems

DCQ Package 6-Pin SOT-223 Top View

Over recommended operating temperature range TJ = -40 to 125°C (unless otherwise noted) (1)

SLVS720F -JUNE 2008-REVISED NOVEMBER 2015

over operating virtual-junction temperature range (unless otherwise noted) (1)

over operating free-air temperature range (unless otherwise noted)

This section highlights some design considerations for implementing this device in various applications.