TPS798-Q1 汽车 50mA、3V 至 50V、微功耗、低压降线性稳压器
- ZHCSU17F March 2009 – April 2024 TPS798-Q1
  
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TPS798-Q1 汽车 50mA、3V 至 50V、微功耗、低压降线性稳压器

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1 特性

符合面向汽车应用的 AEC-Q100 标准：
- 温度等级 1：–40°C 至 +125°C，T_A
宽输入电压范围：3V 至 50V
低静态电流：40μA（典型值）
低压降：300mV（典型值）
输出电流：50mA
无需输入保护二极管
可调输出：从 1.275V 至 28V
关断时静态电流：1μA
与 1μF 输出电容器一起工作时保持稳定
与铝、钽或陶瓷电容器一起工作时保持稳定
反向输入电池保护
反向输出电流保护
热限制
采用 8 引脚 HVSSOP PowerPAD 器件封装

2 应用

低电流、高压稳压器
适用于电池供电系统的稳压器
电信
汽车

典型应用

3 说明

TPS798-Q1 是 50V 高压微功耗低压降 (LDO) 线性稳压器系列中的首款器件。该器件能够提供 50mA 的输出电流，而压降电压仅为 300mV。TPS798-Q1 专为低静态电流高压 (50V) 应用而设计，具有 40μA 的工作电流和 1μA 的关断电流，因此非常适合电池供电或高压系统。静态电流在压降中也得到了很好的控制。

TPS798-Q1 的其他特性包括能够与低等效串联电阻 (ESR) 陶瓷输出电容器一起工作。该器件很稳定，输出端上仅为 1μF；大多数旧器件需要 10μF 至 100μF 钽电容器才能保持稳定性。与其他稳压器一同使用时的常见情况一样，在无需额外等效串联电阻 (ESR) 的前提下可使用小型陶瓷电容器。内部保护电路包括反向输入电池保护、反向输出电流保护、电流限制和热限制，以在各种故障情况下保护器件。

此器件提供 5V 固定输出电压 (TPS79850)，并具有基准电压为 1.275V 的可调输出电压 (TPS79801)。TPS798-Q1 稳压器采用带有外露焊盘的 8 引脚 HVSSOP PowerPAD (DGN) 封装，可增强热管理功能。

封装信息

器件型号	封装⁽¹⁾	封装尺寸⁽²⁾
TPS798-Q1	DGN（HVSSOP，8）	3mm x 4.9mm

(1) 如需更多信息，请参阅机械、封装和可订购信息。

(2) 封装尺寸（长 × 宽）为标称值，并包括引脚（如适用）。

4 Pin Configuration and Functions

TPS798-Q1 DGN Package,8-Pin HVSSOP With PowerPAD
(Top View)

The exposed thermal pad is connected to ground through pin 4 (GND).

Figure 4-1 DGN Package,8-Pin HVSSOP With PowerPAD™ (Top View)

Table 4-1 Pin Functions

PIN		TYPE	DESCRIPTION
NAME	NO.	TYPE	DESCRIPTION
EN	5	I	Enable pin. Driving the EN pin high turns on the regulator over full operating range. Driving this pin low puts the regulator into shutdown mode over full operating range.
GND	4	O	Ground. The exposed thermal pad is connected to ground through this pin.
IN	8	I	Input pin. Place a 0.1μF ceramic or greater capacitor from this pin to ground to provide stability. Both input and output capacitor grounds must be tied back to the device ground with no significant impedance between them.
NC	3, 6, 7	—	No internal connection
OUT	1	O	Regulated output voltage pin. A small (1μF) capacitor is needed from this pin to ground to provide stability.
SENSE/FB	2	I	This pin is the input to the control loop error amplifier. Use this pin to set the output voltage of the device.

5 Specifications

5.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)⁽¹⁾

			MIN	MAX	UNIT
V_IN	Input voltage range	IN⁽²⁾	–65	60	V
		OUT	–0.3	28
		FB	–0.3	7
		EN⁽²⁾	–65	60
		Enable to IN differential	0.6	V_IN
T_J	Junction temperature range⁽³⁾		–40	125	°C
T_stg	Storage temperature		–65	150	°C

(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

(2) Transient: 500ms for V_IN > 50V.

(3) The junction temperature must not exceed 125°C. See Figure 5-13 to determine the maximum ambient operating temperature versus the supply voltage and load current. The safe operating area curves assume a 50°C/W thermal impedance and may need to be adjusted to match actual system thermal performance.

5.2 ESD Ratings

				VALUE		UNIT
V_(ESD)	Electrostatic discharge	Human body model (HBM), per AEC Q100-002⁽¹⁾		±2000		V
V_(ESD)	Electrostatic discharge	Charged device model (CDM), per AEC Q100-011		±1000		V

(1) AEC Q100-002 indicates HBM stressing is done in accordance with the ANSI/ESDA/JEDEC JS-001 specification.

5.3 Recommended Operating Conditions

			MIN	MAX	UNIT
V_IN	Input voltage	IN	–65	50	V
		OUT	–0.3	28
		FB	–0.3	7
		EN	–65	50
I_OUT	Output current			50	mA
T_J	Operating junction temperature⁽¹⁾ ⁽²⁾ ⁽³⁾		–40	125	°C
T_A	Ambient free-air temperature		–40	105	°C

(1) Operating conditions are limited by maximum junction temperature. The regulated output voltage specification does not apply for all possible combinations of input voltage and output current. When operating at maximum input voltage, the output current range must be limited. When operating at maximum output current, the input voltage range must be limited.

(2) The TPS798-Q1 is specified to meet performance specifications from –40°C to 125°C operating junction temperature. Specifications over the full operating junction temperature range are specified by design, characterization, and correlation with statistical process controls.

(3) This device includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperature exceeds 125°C (minimum) when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may impair device reliability.

5.4 Thermal Information

THERMAL METRIC⁽¹⁾		TPS798-Q1	UNIT
		DGN (HVSSOP)
		8 PINS
R_θJA	Junction-to-ambient thermal resistance (JEDEC 51-5⁽²⁾)	57.1	°C/W
R_θJA	Junction-to-ambient thermal resistance (JEDEC 51-7⁽³⁾)	130	°C/W
R_θJC(top)	Junction-to-case (top) thermal resistance	50.3	°C/W
R_θJB	Junction-to-board thermal resistance	30.6	°C/W
ψ_JT	Junction-to-top characterization parameter	1.5	°C/W
ψ_JB	Junction-to-board characterization parameter	30.3	°C/W
R_θJC(bot)	Junction-to-case (bottom) thermal resistance	6.5	°C/W

(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application note.

(2) The thermal data is based on using JEDEC 51-5. The copper pad is soldered to the thermal land pattern and using 5 by 8 thermal array (vias). Correct attachment procedure must be incorporated.

(3) The thermal data is based on using JEDEC 51-7. The copper pad is soldered to the thermal land. No thermal vias. Correct attachment procedure must be incorporated.

5.5 Electrical Characteristics

V_IN = V_OUT(NOM) + 1V or 4V (whichever is greater for either fixed or adjustable versions), I_LOAD = 1mA, V_EN = 3V, and C_OUT = C_IN = 2.2μF (unless otherwise noted); for the TPS79801, the FB pin is tied to V_OUT; typical values are at T_J = 25°C

PARAMETER		TEST CONDITIONS		T_J⁽¹⁾	MIN	TYP	MAX	UNIT
V_IN	Minimum input voltage	I_LOAD = 50mA		Full range		3	4	V
Fixed V_OUT	Initial output voltage accuracy	V_IN = V_OUT nom + 0.5V		25°C	–1.5%		1.5%
Fixed V_OUT	Output voltage accuracy over line, load, and full temperature range	V_IN = V_OUT nom + 1V to 50V, I_LOAD = 1mA to 50mA		Full range	–3%		3%
Adjustable V_OUT	Initial output voltage accuracy	V_IN = 3V		25°C	1.256	1.275	1.294	V
Adjustable V_OUT	Output voltage accuracy over line, load, and full temperature range	V_IN = 4V to 50V, I_LOAD = 1mA to 50mA		Full range	1.237	1.275	1.313	V
ΔV_OUT/ΔV_IN	Line regulation, adjustable V_OUT	ΔV_IN = 3V to 50V		Full range			13	mV
ΔV_OUT/ΔV_IN	Line regulation, TPS79850	V_IN = V_OUT nom + 0.5V to 50V		Full range			15	mV
ΔV_OUT/ΔI_OUT	Load regulation, adjustable V_OUT	ΔI_LOAD = 1mA to 50mA		25°C			20	mV
	Load regulation, adjustable V_OUT	ΔI_LOAD = 1mA to 50mA		Full range			32	mV
	Load regulation, fixed V_OUT	ΔI_LOAD = 1mA to 50mA		25°C			50	mV
	Load regulation, fixed V_OUT	ΔI_LOAD = 1mA to 50mA		Full range			90	mV
Adjustable V_OUT	Output voltage range⁽²⁾ ⁽³⁾			Full range	1.275		28	V
V_DO	Dropout voltage⁽⁴⁾ ⁽⁵⁾	V_IN = V_OUT(NOM) – 0.1V		25°C		85	150	mV
		V_IN = V_OUT(NOM) – 0.1V		Full range			190
		I_LOAD = 10mA, V_IN = V_OUT(NOM) – 0.1V		25°C		170	260
		I_LOAD = 10mA, V_IN = V_OUT(NOM) – 0.1V		Full range			350
		I_LOAD = 50mA, V_IN = V_OUT(NOM) – 0.1V		25°C		300	370
		I_LOAD = 50mA, V_IN = V_OUT(NOM) – 0.1V		Full range			550
I_GND	GND pin current⁽⁶⁾	V_IN = V_OUT(NOM)	I_LOAD = 0mA	Full range		30	80	μA
			I_LOAD = 1mA	Full range		100	180
			I_LOAD = 10mA	Full range		400	700
			I_LOAD = 50mA	Full range		1.8	3.3	mA
V_N	Output voltage noise	C_OUT = 10μF, I_LOAD = 50mA, BW = 10Hz to 100kHz, V_IN = 4.3V, V_OUT = 3.3V (adjustable used)		25°C		100		μV_RMS
I_FB	FB pin bias current⁽⁷⁾	V_IN = 3V		25°C		0.05	0.2	μA
V_EN	EN pin high (enabled)⁽⁸⁾	OFF to ON, V_IN = 6V		Full range			1.5	V
	EN pin low (shutdown)⁽⁸⁾	ON to OFF, V_IN = 6V		25°C	0.4 V			V
	EN pin low (shutdown)⁽⁸⁾	ON to OFF, V_IN = 6V		Full range	0.2 V			V
I_EN	EN pin current⁽⁸⁾	V_EN = 0V V_IN = 6V, I_LOAD = 0mA		Full range		0.4	2	μA
I_EN	EN pin current⁽⁸⁾	V_EN = 3V, V_IN = 6V, I_LOAD = 0mA		Full range		0.4	0.5	μA
I_shutdown	GND pin current⁽⁶⁾	V_IN = 6V, V_EN = 0V, I_LOAD = 0mA		Full range		3	25	μA
PSRR	Power-supply rejection ratio	V_IN = 4.3V, V_OUT 3.3V V_RIPPLE = 0.5V_PP, f_RIPPLE = 120Hz, I_LOAD = 50mA		25°C		65		dB
I_LIMIT	Fixed current limit⁽⁹⁾	ΔV_OUT = V_OUT(NOM) – 0.1V		Full range	60		200	mA
I_LIMIT	Adjustable current limit	ΔV_OUT = V_OUT(NOM) – 0.1V		Full range	60		200	mA
I_RL	Input reverse leakage current(reverse battery test)	V_IN = –60V, V_OUT = open, C_IN open		Full range			6	mA
I_RO	Reverse output current⁽¹⁰⁾	V_OUT = V_OUT(NOM), V_IN = ground		25°C		19	25	μA
T_SD	Thermal shutdown temperature (T_J)⁽¹¹⁾	Shutdown, temperature increasing			135			°C
T_SD	Thermal shutdown temperature (T_J)⁽¹¹⁾	Reset, temperature decreasing			135			°C

(1) Full range T_J = –40°C to 125°C.

(2) This parameter is tested and specified under pulse load conditions such that T_J = T_A. This device is 100% production tested at T_A = 25°C. Performance at full range is specified by design, characterization, bench to ATE correlation testing, and other statistical process controls.

(4) This device is limited by a maximum junction temperature of T_J = 125°C. The regulated output voltage specification cannot be applied to all combinations of various V_IN, V_OUT, ambient temperature, and I_OUT conditions. When operating with large voltage differentials across the device, the output load must be limited so as not to violate the maximum junction temperature for a given ambient temperature.

(5) In the adjustable version test, the output uses an external voltage divider. This resistor voltage divider is made up of R₁ = 215kΩ and R2 (bottom resistor) = 340kΩ. This configuration preloads the output with 6μA.

(6) By definition, dropout voltage is the minimum input voltage needed to maintain a given output voltage at a specific load current. For dropout testing, minimum V_IN = V_OUT(NOM) × 0.96. This specification ensures that the device is in dropout and takes into account the output voltage tolerance over the full temperature range.

(7) Ground pin current is tested with V_IN = V_OUT(NOM) or 3V, whichever is greater.

(8) FB pin current flows into the FB pin.

(9) EN pin current flows into the EN pin.

(10) Current limit is tested with V_IN = V_OUT(NOM) + 0.5V or 3V, whichever is greater. V_OUT is forced to V_OUT(NOM) – 0.1V and the output current is measured.

(11) Reverse output current is tested with the IN pin tied to ground and the output forced to V_OUT(NOM) +0.1V. This current flows into the OUT pin and out of the GND pin and then measured.

(12) Specified by design.

5.6 Dissipation Ratings

see ⁽¹⁾

BOARD	PACKAGE	DERATING FACTOR ABOVE T_A = 25°C	T_A ≤ 25°C POWER RATING	T_A = 70°C POWER RATING	T_A = 85°C POWER RATING
High-K⁽²⁾	DGN	16.6mW/°C	1.83W	1.08W	0.833W

(1) See the Thermal Considerations for more information related to thermal design.

(2) The JEDEC High-K (1s) board design used to derive this data was a 4.5 inch × 3 inch, 2-layer board with 2 ounce copper traces on top of the board.

5.7 Typical Characteristics

TPS798-Q1 Line
Regulation vs Input Voltage

Figure 5-1 Line Regulation vs Input Voltage

TPS798-Q1 Dropout Voltage vs Output Current

Figure 5-3 Dropout Voltage vs Output Current

TPS798-Q1 Quiescent Current vs Temperature

Figure 5-5 Quiescent Current vs Temperature

TPS798-Q1 Quiescent Current vs Input Voltage

Figure 5-7 Quiescent Current vs Input Voltage

TPS798-Q1 Quiescent Current vs Output Current

Figure 5-9 Quiescent Current vs Output Current

TPS798-Q1 Reverse Battery Leakage vs Input Voltage

Figure 5-11 Reverse Battery Leakage vs Input Voltage

Figure 5-13 Safe Operating Area

Figure 5-2 Line Regulation vs Input Voltage

Figure 5-4 Dropout Voltage vs Output Current

Figure 5-6 Quiescent Current vs Temperature

Figure 5-8 Quiescent Current vs Input Voltage

Figure 5-10 Quiescent Current vs Output Current

TPS798-Q1 Power
Supply Ripple Rejection vs Frequency

Figure 5-12 Power Supply Ripple Rejection vs Frequency

6 Detailed Description

6.1 Overview

The TPS798-Q1 is a 50mA high-voltage LDO regulator with micropower quiescent current and shutdown. The device is capable of supplying 50mA at a dropout voltage of 300mV (typical). The low operating quiescent current (40μA) drops to 1μA in shutdown. In addition to the low quiescent current, the TPS798-Q1 incorporates several protection features that make it ideal for battery-powered applications.

The device is protected against both reverse-input and reverse-output voltages. In battery-backup applications, where the output can be held up by a backup battery when the input is pulled to ground, the TPS798-Q1 acts as if a diode is in series with the device output and prevents reverse current flow. Figure 6-1 and Figure 6-2 illustrate two typical applications.

TPS798-Q1 Constant Brightness for Indicator LED Over Wide Input Voltage Range

I_LED = 1.275V / R_SET –48V can vary from –4V to –50V.

Figure 6-1 Constant Brightness for Indicator LED Over Wide Input Voltage Range

Figure 6-2 Kelvin Sense Connection

6.2 Functional Block Diagrams

Figure 6-3 Fixed Voltage Output Version

TPS798-Q1 Adjustable Voltage Output Version

Figure 6-4 Adjustable Voltage Output Version

6.3 Feature Description

6.3.1 Adjustable Operation

The TPS798-Q1 has an output voltage range of 1.275V to 28V. The output voltage is set by the ratio of two external resistors as shown in Figure 6-5. The feedback loop monitors the output to maintain the voltage at the adjust pin at 1.275V referenced to ground. The current in R₁ is then equal to 1.275V / R₁, and the current in R₂ is the current in R₁ plus the FB pin bias current. The FB pin bias current, 0.2μA at 25°C, flows through R₂ into the FB pin. The output voltage can be calculated using the formula in Figure 6-5. The value of R₁ must be less than 250kΩ to minimize errors in the output voltage caused by the FB pin bias current. When in shutdown, the output is turned off and the divider current is zero.

Figure 6-5 Adjustable Operation

A 100pF capacitor (C₁) placed in parallel with the top resistor (R₂) of the output divider is necessary for stability and transient performance of the adjustable TPS798-Q1. The impedance of C₁ at 10kHz must be less than the value of R₂.

The adjustable device is tested and specified with the FB pin tied to the OUT pin and a 1mA DC load (unless otherwise specified) for an output voltage of 1.275V. Specifications for output voltages greater than 1.275V are proportional to the ratio of the desired output voltage to 1.275V (V_OUT / 1.275V). For example, load regulation for an output current change of 1mA to 50mA is –10mV (typical) at V_OUT = 1.275V.

At V_OUT = 12V, load regulation is:

Equation 1. (12V / 1.275V) × (–10mV) = –94mV

6.3.2 Output Capacitance and Transient Response

The TPS798-Q1 is designed to be stable with a wide range of output capacitors. The ESR of the output capacitor affects stability, most notably with small capacitors. To prevent oscillations, use a minimum output capacitor of 1μF with an ESR of 3Ω or less. The TPS798-Q1 is a micropower device, and output transient response is a function of output capacitance. Larger values of output capacitance decrease the peak deviations and provide improved transient response for larger load current changes. Bypass capacitors, used to decouple individual components powered by the TPS798-Q1, increase the effective output capacitor value.

Extra consideration must be given to the use of ceramic capacitors. Ceramic capacitors are manufactured with a variety of dielectrics, each with different behavior over temperature and applied voltage. The most common dielectrics used are Z5U, Y5V, X5R, and X7R. The Z5U and Y5V dielectrics are good for providing high capacitances in a small package, but exhibit strong voltage and temperature coefficients. When used with a 5V regulator, a 10μF Y5V capacitor can exhibit an effective value as low as 1μF to 2μF over the operating temperature range. The X5R and X7R dielectrics result in more stable characteristics and are more suitable for use as the output capacitor. The X7R type has better stability across temperature, while the X5R is less expensive and is available in higher values.

Voltage and temperature coefficients are not the only sources of problems. Some ceramic capacitors have a piezoelectric response. A piezoelectric device generates voltage across the terminals because of mechanical stress, similar to the way a piezoelectric accelerometer or microphone works. For a ceramic capacitor, the stress can be induced by vibrations in the system or thermal transients.

6.3.3 Calculating Junction Temperature

Given an output voltage of 5V, an input voltage range of 15V to 24V, an output current range of 0mA to 50mA, and a maximum ambient temperature of 50°C, the maximum junction temperature is calculated as follows.

The power dissipated (P_DISS) by the DGN package is equal to:

Equation 2. I_OUT(MAX)(V_IN(MAX) – V_OUT) + I_GND(V_IN(MAX))

where:

I_OUT(MAX) = 50mA
V_IN(MAX) = 24V
V_OUT = 5V
I_GND at (I_OUT = 50mA, V_IN = 24V) = 1mA

Therefore,

Equation 3. P_DISS = 50mA (24V – 5V) + 1mA (24V) = 0.974W

The thermal resistance is approximately 60°C/W, based on JEDEC 51-5 profile. Therefore, the junction temperature rise above ambient is approximately equal to:

Equation 4. 0.974W × 60°C/W = 58.44°C

The maximum junction temperature is then equal to the maximum junction temperature rise above ambient plus the maximum ambient temperature or:

Equation 5. T_J max = 50°C + 58.44°C = 108.44°C

6.3.4 Protection Features

The TPS798-Q1 incorporates several protection features that make the device designed for use in battery-powered circuits. In addition to the normal protection features associated with monolithic regulators, such as current limiting and thermal limiting, the device is protected against reverse-input voltages, and reverse currents 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. The junction temperature must not exceed 125°C.

The input of the device withstands reverse voltages of –60V. Current flow into the device is limited to less than 6mA (typically, less than 100μA), and no negative voltage appears at the output. The TPS798-Q1 protects both the device and the load. This architecture also provides protection against batteries that can be plugged in backwards.

The FB pin of the adjustable device can be pulled above or below ground by as much as 7V without damaging the device. If the input is left open or grounded, the FB pin behaves as an open circuit when pulled below ground, or as a large resistor (typically, 100kΩ) in series with a diode when pulled above ground. If the input is powered by a voltage source, pulling the FB pin below the reference voltage increases the output voltage. This configuration causes the output to go to a unregulated high voltage. Pulling the FB pin above the reference voltage turns off all output current.

In situations where the FB pin is connected to a resistor divider that pulls the FB pin above the 7V clamp voltage if the output is pulled high, the FB pin input current must be limited to less than 5mA. For example, a resistor divider provides a regulated 1.5V output from the 1.275V reference when the output is forced to 28V. The top resistor of the resistor divider must be chosen to limit the current into the FB pin to less than 5mA when the FB pin is at 7V. The 21V difference between the OUT and FB pins divided by the 5mA maximum current into the FB pin yields a minimum top resistor value of 5.8kΩ.

In circuits where a backup battery is required, several different input and output conditions can occur. The output voltage can be held up while the input is either pulled to ground, pulled to some intermediate voltage, or is left open. The rise in reverse output current above 7V occurs from the breakdown of the 7V clamp on the FB pin. With a resistor divider on the regulator output, this current is reduced, depending on the size of the resistor divider.

When the IN pin of the TPS798-Q1 is forced below the OUT pin, or the OUT pin is pulled above the IN pin, input current typically drops to less than 0.6mA. This scenario can occur if the input of the TPS798-Q1 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 EN pin has no effect on the reverse output current when the output is pulled above the input.

6.4 Device Functional Modes

6.4.1 Low-Voltage Tracking

At low input voltages, the regulator drops out of regulation and the output voltage tracks input minus a voltage based on the load current and switch resistance. This allows for a smaller input capacitor and can possibly eliminate the need of using a boost convertor during cold-crank conditions.