Getting Started with the AEK-POW-LDOV02X Dual Linear Voltage Regulator Evaluation Board

Introduction

In the automotive industry, a low-dropout linear regulator (LDO) provides effective voltage ripple suppression and electromagnetic compatibility (EMC) performance, particularly when compared to DC-DC converters. LDOs are crucial for systems operating in harsh environments, such as vehicles.

In modern automotive designs, a 12 V battery typically powers the system. While a stable lower-voltage supply is required for system operation, constantly changing load conditions and environmental factors cause variations in the 12 V supply. An automotive battery-direct-connect LDO converts a harsh high-voltage supply into a stable lower-voltage output.

Moreover, thermal performance is always a critical concern for battery-direct-connection LDOs. The LDO connected to a car battery needs to convert the battery voltage down to 5 V, 3.3 V, or even lower voltage for powering MCU, CAN bus, and other devices. In these situations, the voltage drop on the LDO might be very high, and power dissipation on the LDO might even exceed 1 W for a 100-mA loading current. If the system demands several hundred milliamps of current, a single LDO cannot handle the power dissipation.

For automotive off-board sensors and small current off-board modules, systems must consider their power supplies with respect to both protection and output accuracy. In these systems, the power supply runs through a long cable from the main board. The long cable might be damaged in the harsh automotive environment, potentially causing short-to-ground or short-to-battery conditions on the power supply output. In such cases, the system must implement a protection mechanism to safeguard on-board components from damage.

Additionally, it is essential to minimize the voltage-tracking tolerance between the off-board sensor power supply and the MCU/ADC power supply. An ultra-low tolerance tracking voltage for the off-board sensor power supply is critical in achieving high-quality data acquisition. A voltage-tracking LDO is an ideal solution for driving the off-board loads. Voltage-tracking LDOS provide comprehensive protection features, including short-to-ground, short-to-battery, overload protection, thermal protection, and ultra-accurate output tracking voltage.

Our AEK-POW-LDOV02X evaluation board addresses this challenge, thanks to the L99VR02XP dual linear voltage regulator, reaching a higher output current and distributing power consumption among multiple devices.

The L99VR02XP operates with reduced input voltage, minimizing internal power dissipation and maximizing the sourcing current capability. Output current limitation protects the regulator and the application from overload conditions, such as short to ground.

Thanks to its operating temperature range (Tj=-40°C to 175°C), the device is suitable for electronic applications with high temperature environments and for applications that require stable power supplies (for example, navigation systems, microcontroller supplies, audio systems, automotive display drivers, sensors, infotainment processors, and powertrain systems).

The board features two output voltages, with two LDOs (LDO1 and LDO2), providing low ripple and excellent noise immunity. LDO2 performs automatic voltage tracking and de-tracking of LDO1, or of an external LDO voltage, thus representing an accurate solution for automotive off-board sensors and small current off-board modules.

This feature is important in complex systems with multiple power supply voltages where it is necessary for one voltage to reach its value before another, or for two voltages to reach the same value simultaneously. Additionally, this feature helps minimize high voltage differences between connected power supplies, reducing inrush currents.

The board also features some automotive safety mechanisms, such as a watchdog per LDO, generated from an external MCU, which allows real-time monitoring of device correct operation. Another key safety feature is advanced on-chip temperature control. In fact, the L99VR02XP outputs are split into two different temperature clusters with dedicated thermal sensors. If the temperature of a cluster reaches the thermal protection threshold, only the relevant output is turned off while the other one remains active.

Safety mechanisms

The AEK-POW-LDOV02X evaluation board implements the following automotive safety mechanisms:

• Output voltage monitoring: Two independent reset circuits supervise the VO_LDO1,2 output voltages. If at least one output voltage falls below V_{O_th_LDO1,2} threshold (equal to V_O-10% V_O1,2), the RST_LDO1,2 pins are pulled low.
• Active connection monitoring (MCU-connected configuration only): For continuous connection monitoring between the MCU and the two LDOs, a watchdog is employed. The watchdog signal (generated by the MCU and applied to the AEK-POW-LDOV02X WI1,2 pins) is a square wave with 50% duty cycle. The frequency value depends on both the output voltage and the chosen C7 capacitor value for LDO1 and C14 capacitor value for LDO2. The LDO devices monitor the watchdog signal provided by the MCU. If the signal frequency is outside the range described above, the RST1,2 pins are pulled low. You can disable the watchdog by placing a jumper on JP1 for LDO1 and a jumper on JP2 for LDO2.
• Regulator enabling and disabling: The L99VR02XP voltage regulator is enabled/disabled through two independent enable pins, EN1,2. Remove JP6 and JP13 jumpers to enable LDO1,2 output voltage. Put JP6 and JP13 jumpers to disable LDO1,2 output voltage.
• Output current limitation: The current output limitation protects the regulator in case of current overload or short-to-ground. The overcurrent limit is set by regulating the value of a multiturn variable resistor (trimmer) on the AEK-POW-LDOV02X I_short pins. To increase or decrease I_{short_LDO1}, turn TR1 trimmer, respectively in counterclockwise or clockwise direction. To increase or decrease I_{short_LDO2}, turn TR2 trimmer, respectively in counterclockwise or clockwise direction. If the LDO1,2 overcurrent limit is reached, the RST1,2 pins are pulled low.
• Thermal warning detection: To warn the microcontroller about a severe temperature increase of the LDO, two thermal warning outputs have been implemented (one for each regulator). If the device detects a junction temperature above 150°C, the related advanced thermal warning (TW_LDO1,2) pin is pulled low, while the specific voltage regulator and its features remain active.
• Overvoltage warning detection: The TW_LDO1,2 pins also provide diagnostics about the output overvoltage. To distinguish between a thermal and an overvoltage warning event, two different signals are generated on the same TW_LDO1,2 output pin. A thermal warning event detection sets the TW_LDO1,2 pins low, whereas an output overvoltage event generates a square wave (duty cycle = 50% and period = 300 microseconds) on the TW_LDO1,2 pins.
• Reverse polarity protection: To prevent reverse battery polarity, a protection block has been added to rail input lines (VS_LDO1,2).

Overview

Board features

The board key features are:

• L99VR02XP dual automotive-grade linear voltage regulator
• User-selectable output voltages (0.8, 1.2, 1.5, 1.8, 2.5, 2.8, 3.3, and 5 V) with up to 250 mA load current capability per channel (LDO1 and LDO2)
• Protection and diagnostic features: Enable pin for enabling/disabling the voltage regulator, Reset, Watchdog, Advanced thermal warning with output overvoltage detection, Undervoltage lockout, Programmable short-circuit output current (I_short), Fast output discharge, Short-to-battery output protection.
• The two internal LDOs have separate thermal clusters and temperature sensors
• Thermal shutdown and short-circuit protection
• LDO2 automatic voltage tracking and de-tracking with respect to LDO1, or to an external voltage regulator

Block diagram

The figure below shows the AEK-POW-LDOV02X overall architecture diagram, related to the two LDOs, with protection blocks (detailed in Figure 5. VS_LDO1,2 protection block position), power supplies (VBAT1,2 for LDO1,2), connectors (CN1A, CN2A, CN1B, CN2B), capacitors for supply backup and high-frequency noise filtering (Cout_LDO1,2), and signals (tracking mode, watchdog, thermal warning, overvoltage, enable, reset and ADC).

Hardware overview

Hardware description

Hardware overview

The AEK-POW-LDOV02X evaluation board is equipped with four connectors for MCU-connected mode only:

• CN1A and CN1B related to LDO1
• CN2A and CN2B related to LDO2

Functional blocks

As shown in the figure below, the board is functionally divided into two blocks along the horizontal axis: the lower part manages LDO1, while the upper part manages LDO2.

Hardware architecture

The AEK-POW-LDOV02X evaluation board is equipped with four connectors for MCU-connected mode only:

• CN1A and CN1B related to LDO1
• CN2A and CN2B related to LDO2

Enable pins

Two independent enable inputs (EN_LDO1,2) enable/disable the L99VR02XP. A high-voltage signal switches the regulator on. When the enable pins are set to low, the VO1 and VO2 outputs are switched off. The current consumption of the device is about 1 µA and the fast output discharge circuit is activated.

When using an external MCU board, signals coming from the MCU must be:

• MCU_LDO1,2_EN = 0 to enable the LDOs
• MCU_LDO1,2_EN = 1 to disable the LDOs

To change the output voltages while the regulators are on, apply a pulse signal to the EN_LDO1,2 input pins after setting SELx_LDOY pins (see table 25). The L99VR02XP needs a low enable signal (En_LDO1,2) to acquire the input level of SELx_LDOY and select the output voltage accordingly.

Output voltage selection

The L99VR02XP provides up to eight different output voltage options for each output. The combination of its three digital input selectors (SELx_LDOY) determines the output voltage according to the following truth table.

The SELx_LDOy pin configuration is acquired at the device startup (in about 500 µs). Once the configuration is set, the output voltage cannot be changed until the next EN_LDO1,2 pin transition. If all SELx_LDOy pins are left unconnected, the default configuration is applied.

Reset pins

Two independent reset circuits supervise the output voltages VO1,2. The reset circuit is active when EN_LDO1,2 is high. As the reset pin (RS 1,2) is an open-drain output, a 10 kΩ resistor, connected to Vext, is used to pull it up (refer to AEK-POW-LDO02X schematic). When VO1,2 falls below the threshold (= VO1,2 -10% of VO1,2), the reset RS 1,2 signal generates a low logic level. C6 and C13 capacitors are used to increase the delay after VO1,2 > (VO1,2-10% of VO1,2), holding the RS signal down (to GND). The delay time is calculated through the following equation:

Trd = (2.2 V) / (Icr_LDO1,2) * Ctr

Where: Trd = delay time, Icr_LDO1,2 = current, Ctr = capacitor value. We selected 2.2 nF for Ctr (C6=C13 in the board schematic diagrams) with a delay time in the range: Trd = 162µs to 605µs (measured at about 300µs).

Note: When the RST pin is pulled low, be aware that the current flowing through the RST pin may affect the watchdog activation or deactivation.

Autonomous watchdog

The L99VR02XP features an autonomous watchdog, which is an automotive safety mechanism used to monitor continuous connection with an external MCU. Up to two supplied microcontrollers are monitored by the watchdog inputs, Wi_LDO1,2. The watchdog signals are generated by the MCU and provided as inputs to the AEK-POW-LDOV02X Wi_LDO1,2 pins, respecting a specific time window.

If this window is not respected, the MCU triggers a reset signal that indicates a malfunction and resets the device. If pulses are missing, the relative RST_LDO1,2 output pins are set low. The watchdog timeout can be set within a wide range with the external capacitor, Ctw. The watchdog circuits discharge the capacitor Ctwx, with the constant current ICWd_LDO1,2.

If the lower threshold (Vwlth_LDO1,2) is reached, a watchdog reset is generated. To prevent this from happening, the microcontroller must generate a positive edge during the discharge of the capacitors before the voltage reaches the threshold Vwlth_LDO1,2.

The time window is calculated through the following equations:

(Vwhth_LDO1,2 - Vwlth_LDO1,2) × Ctw = ICWd_LDO1,2 × Td

(Vwhth_LDO1,2 - Vwlth_LDO1,2) × Ctw = ICWC_LDO1,2 × Twol

Twop = Td+Twol

Where: Vwhth_LDO1,2 = VO1,2 high threshold (50% of VO1,2), Vwith_LDO1,2 = VO1,2 low threshold (16% of VO1,2), Ctw = external capacitor value, IcWc_LDO1,2 = Ctw current, Td = Ctw charging time, Twol = Ctw discharging time. The sum of Td and Twol determines the time window Twop. During this time window, the watchdog signal must change state. The rising edge triggers the capacitor to transition from discharge to charge.

Thermal warning and thermal shutdown

To warn the microcontroller about a severe temperature increase, two thermal warning outputs have been implemented (one for each regulator). Through TC_CONF it is possible to set the management of a thermal shutdown event.

Thermal clusters

To provide advanced on-chip temperature control, the L99VR02XP outputs are split into two different temperature clusters with dedicated thermal sensors.

When the TC_CONF pin is high, the two clusters are linked to each other:

• If LDO1 is in thermal shutdown, LDO2 also is switched off
• If LDO2 is in thermal shutdown, LDO1 keeps the normal activity

When the TC_CONF pin is low, only the cluster that reached protection temperature is switched off:

• LDO1 and LDO2 are fully independent of each other and monitored by two different thermal clusters
• In tracking mode: if LDO1 is in thermal shutdown and TRK_MODE = GND, LDO2 is untied from LDO1 and keeps the normal activity.

Overvoltage detection and thermal warning

The TW_LDO1,2 pins provide output overvoltage (OV_LDO1,2) diagnostics. To distinguish between a thermal warning event and an output overvoltage event, two different signals are generated on the same TW_LDO1,2 output pins. A thermal warning event detection sets the TW_LDO1,2 pins low. An output overvoltage event generates a square wave on the TW_LDO1,2 pins. Overvoltage detection has a higher priority than thermal warning detection. Therefore, if both protections are triggered, the generated signal is a square wave.

The period of signal in TW in the over voltage status is: 160µs ≤ Tw_per_LDO1,2≤ 350µs with frequency: 2.8KHz ≤ Tw_fre_LDO1,2 ≤ 6.25KHz.

Fast output discharge

To ensure a quick discharge of the external capacitors (tied on the output pins) down to around 1.3 V, the L99VR02XP uses two internal pull-down circuits. When the EN_LDO1,2 pins go low, during thermal shut-down and undervoltage lockout, the output currents flow to the ground through the pull-down resistors of the fast output discharge circuit.

The fast output discharge feature is available for the following output voltages:

• VO_LDO1,2 = 2.5 V (SELx = [1;0;0])
• VO_LDO1,2 = 2.8 V (SELx = [1;0;1])
• VO_LDO1,2 = 3.3 V (SELx = [1;1;0])
• VO_LDO1,2 = 5 V (SELx = [1;1;1])

Note: For further information, refer to DS14686

Automatic voltage tracking and de-tracking of LDO1 or tracking of an external LDO

Voltage tracking and de-tracking are solutions adopted when long cables supply off-board loads with voltage regulators located on the main module. Under these operating conditions, short-to-ground and short-to-battery protections oppose possible electrical failures caused by cable damage.

In the L99VR02XP, LDO2 can be a tracker of LDO1 or of an external voltage regulator. This function is enabled by TRK_MODE pin, IN_TRK pin and TRK_STAT, as detailed in the following table.

The IN_TRK (input pin) is used to select LDO1, an external LDO, or GND. Put a jumper on JP15 to select:

• LDO1 (positions 5-6)
• Ext_LDO (positions 1-2): in this case, LDO2 tracks an external LDO
• GND (positions 3-4)

The TRK_STAT pin indicates to the MCU if the LDO2 is in tracking mode or working as an independent regulator. During the startup phase (soft start), if the tracking mode is disabled or LDO2 is in UV/OV, the TRK_STAT pin is set to low. After startup, without UV/OV faults, when the tracking mode is activated, the TRK_STAT pin goes high. If the device is configured with LDO2 tracking LDO1 and the LDO1 soft-start signal is high, the tracking comparators are ignored to avoid unwanted transient effects during standard startup in the tracking with LDO1. When the TRK_STAT (output pin) is high, the LDO2 is in tracking state. If the output pin is low, the LDO2 is in de-tracking state. The high logic level depends on the V-Ex voltage (5 VDC).

In tracking mode, if the jumper position of Sel1,2,3_LDO1 ≠ Sel1,2,3_LDO2 (see Table 5. Jumper description and Figure 9. Jumper position), the LDO2 acts as a fully independent regulator.

If the ramp-up phase is successful, the state machine transitions from the "RAMP in standalone reg." state to the "Standalone reg. state". If EN pin is equal to 0 or an undervoltage occurs, the state machine enters "LDO2 OFF" state and LDO2 is switched off.

If TRK_COND is true, the device enters "RAMP in tracking mode" state. Then, it enters the "RAMP in tracking mode" state and finally the "Tracking mode reg.". According to the image above, TRK_COND is true when all the following conditions occur: EN_LDO2=1, TRK_MODE=1, IN_TRK_UV/OV=0, Sel1,2,3_LDO1 = Sel1,2,3_LDO2, Thermal fault LDO1=0, UVLO VS_LDO1=0. During the sof-start phase, IN_TRK_UV/OV logic state is not considered.

If TRK_COND is false, the device goes back to the "Detrack procedure" state. According to the image above, TRK_COND is false when the following conditions occur: EN_LDO2=0, TRK_MODE=0, IN_TRK_UV/OV=1, Sel1,2,3_LDO1 ≠ Sel1,2,3_LDO2, Thermal fault LDO1=1, UVLO VS_LDO1=1. The device remains in "Detrack procedure" state until a fast discharge condition (EN_LDO2=0) or an undervoltage occurs on LDO2. In these cases, the device enters the "RAMP in standalone reg." state, and the state machine cycle starts again.

Note: For further information, refer to DS14686

AutoDevKit ecosystem

AutoDevKit demo application

The upcoming AutoDevKit version 2.7.0 includes a demo application whose goal is to vary the output voltage of both channels of the device among the 8 different supported levels in a cycle, with a delay of 3 seconds between each transition. The L99VR02XP_dev_init() and L99VR02XP_dev_poweron() functions require the device name as argument and perform, respectively, the initialization and the start-up of both device channels at the default operation mode (0.8V).

The L99VR02XP_ch_changeVOut() function requires the channel name and an operation mode. This function changes the channel output voltage by applying the given operation mode.

Demo code

/* Application entry point. */
int main(void) {
  /* Initialization of all the imported components in the order specified in
     the application wizard. The function is generated automatically.*/
  componentsInit();
  irqIsrEnable();
  L99VR02XP_dev_init(L99VR02XP_DEV0);
  L99VR02XP_dev_powerOn (L99VR02XP_DEV0);
  /* Application main loop. */
  for (;;) {
    osalThreadDelayMilliseconds (3000);
    L99VR02XP_ch_changeVOut (L99VR02XP_DEV0, L99VR02XP_CH1, L99VR02XP_CH_VOLTAGE_1_2_V);
    L99VR02XP_ch_changeVOut (L99VR02XP_DEV0, L99VR02XP_CH2, L99VR02XP_CH_VOLTAGE_1_2_V);
    osalThreadDelayMilliseconds (3000);
    L99VR02XP_ch_changeVOut(L99VR02XP_DEV0, L99VR02XP_CH1, L99VR02XP_CH_VOLTAGE_1_5_V);
    L99VR02XP_ch_changeVOut(L99VR02XP_DEV0, L99VR02XP_CH2, L99VR02XP_CH_VOLTAGE_1_5_V);
    osalThreadDelayMilliseconds (3000);
    L99VR02XP_ch_changeVOut (L99VR02XP_DEV0, L99VR02XP_CH1, L99VR02XP_CH_VOLTAGE_1_8_V);
    L99VR02XP_ch_changeVOut (L99VR02XP_DEV0, L99VR02XP_CH2, L99VR02XP_CH_VOLTAGE_1_8_V);
    osalThreadDelayMilliseconds (3000);
    L99VR02XP_ch_changeVOut (L99VR02XP_DEV0, L99VR02XP_CH1, L99VR02XP_CH_VOLTAGE_2_5_V);
    L99VR02XP_ch_changeVOut (L99VR02XP_DEV0, L99VR02XP_CH2, L99VR02XP_CH_VOLTAGE_2_5_V);
    osalThreadDelayMilliseconds (3000);
    L99VR02XP_ch_changeVOut (L99VR02XP_DEV0, L99VR02XP_CH1, L99VR02XP_CH_VOLTAGE_2_8_V);
    L99VR02XP_ch_changeVOut (L99VR02XP_DEV0, L99VR02XP_CH2, L99VR02XP_CH_VOLTAGE_2_8_V);
    osalThreadDelayMilliseconds (3000);
    L99VR02XP_ch_changeVOut (L99VR02XP_DEV0, L99VR02XP_CH1, L99VR02XP_CH_VOLTAGE_3_3_V);
    L99VR02XP_ch_changeVOut (L99VR02XP_DEV0, L99VR02XP_CH2, L99VR02XP_CH_VOLTAGE_3_3_V);
    osalThreadDelayMilliseconds (3000);
    L99VR02XP_ch_changeVOut (L99VR02XP_DEV0, L99VR02XP_CH1, L99VR02XP_CH_VOLTAGE_5_V);
    L99VR02XP_ch_changeVOut(L99VR02XP_DEV0, L99VR02XP_CH2, L99VR02XP_CH_VOLTAGE_5_V);
    osalThreadDelayMilliseconds (3000);
    L99VR02XP_ch_changeVOut(L99VR02XP_DEV0, L99VR02XP_CH1, L99VR02XP_CH_VOLTAGE_0_8_V);
    L99VR02XP_ch_changeVOut (L99VR02XP_DEV0, L99VR02XP_CH2, L99VR02XP_CH_VOLTAGE_0_8_V);
  }
}

APIs

The following functions are available for the AEK-POW-LDOV02X device:

• void L99VR02XP_dev_init (L99VR02XP dev name t devName);: Initializes the AEK-POW-LDOV02X device.
• void L99VR02XP_dev_powerOn(L99VR02XP_dev_name_t devName);: Turns on both channels of a specific AEK-POW-LDOV02X device.
• void L99VR02XP_ch_enable(L99VR02XP_dev_name_t devName, L99VR02XP_ch_name_t chName);: Enables a specific channel of a specific AEK-POW-LDOV02X device.
• void L99VR02XP_ch_disable(L99VR02XP_dev_name_t devName, L99VR02XP_ch_name_t chName);: Disables a specific channel of a specific AEK-POW-LDOV02X device.
• L99VR02XP_ch_sts_t L99VR02XP_ch_getEnablingSts(L99VR02XP_dev_name_t devName, L99VR02XP_ch_name_t chName);: Returns the enabling status of a channel (DISABLED, ENABLED) of a specific AEK-POW-LDOV02X device.
• L99VR02XP_ch_vout_chng_retCode_t L99VR02XP_ch_changeVOut(L99VR02XP_dev_name_t devName, L99VR02XP ch name t chName, L99VR02XP ch opMode t opMode);: Sets the output voltage of a specific channel of a specific AEK-POW-LDOV02X device.
• void L99VR02XP dev startLDO1Tracking (L99VR02XP dev name t L99VR02XP dev name);: Makes LDO2 tracker of LDO1 Out Voltage (if the JP-INTRK jumper JP15 is set accordingly in position 5-6) in a specific AEK-POW-LDOV02X device.
• void L99VR02XP dev startExtTracking (L99VR02XP dev name t L99VR02XP dev name, L99VR02XP_ch_opMode_t L99VR02XP_ch_opMode);: Makes LDO2 tracker of an external regulator in a specific AEK-POW-LDOV02X device, if the following conditions are verified: the JP-INTRK jumper JP15 is set accordingly in position 1-2; an external voltage, equal to one of those supported by the device, is supplied in LDO-ex pin in connector CN2A; the L99VR02XP_ch_opMode argument is equal to the supplied external voltage.
• L99VR02XP_ch_fsm_sts_t L99VR02XP_ch_getFsmState(L99VR02XP_dev_name_t devName, L99VR02XP ch name t chName);: Returns the status of a channel (POWER_OFF, DISABLED, NORMAL, CHANGING_VOUT, UNKNOWN) of a specific AEK-POW-LDOV02X device.
• L99VR02XP_ch_error_fsm_t L99VR02XP_ch_getErrorFsmState (L99VR02XP_dev_name_t devName, L99VR02XP ch name t chName);: Returns the error status of a channel (NONE, WARNING, ERROR, UNKNOWN) of a specific AEK-POW-LDOV02X device.
• L99VR02XP_ch_rst_fsm_t L99VR02XP_ch_getRSTFsmState (L99VR02XP_dev_name_t devName, L99VR02XP ch name t chName);: Returns the status related to the RST pin of a channel (IDLE, NORMAL, WD_MISSING, UNDERVOLTAGE, UNKNOWN) of a specific AEK-POW-LDOV02X device.
• L99VR02XP_ch_tw_fsm_t L99VR02XP_ch_getTWFsmState (L99VR02XP_dev_name_t devName, L99VR02XP ch name t chName);: Returns the status related to the TW pin of a channel (NORMAL, THERMAL_WARNING, OVERVOLTAGE, UNKNOWN) of a specific AEK-POW-LDOV02X device.

How to configure the AEK-POW-LDOVO2X evaluation board

The AEK-POW-LDOV02X board operates in two modes:

• Auto mode or MCU-connected configuration: the board settings are managed through an external microcontroller unit (MCU).
• Manual mode: the board works standalone, that is, without an MCU, and settings are defined via dedicated jumpers.

In both modes, place jumpers on JP16 and JP14, as shown in the figure below.

Auto mode

In auto mode, the board is configured and controlled by an external MCU through CN1A, CN2A, CN1B, and CN2B connectors. To use the board in this mode, simply remove all jumpers, except the ones on JP14 and JP16.

Manual mode

To use the board in this mode, follow the procedure below:

1. Place/remove jumpers on JP6 and JP13 to disable/enable LDO1 and LDO2, respectively.
2. Place jumpers on JP1 and JP2 to disable the watchdogs for both LDOs.
3. Select the output voltage values (Vout1 and Vout2) for LDO1 and LDO2 according to table 7 and jumpers on: JP7, JP8, JP9 for LDO1; JP10, JP11, JP12 for LDO2.
4. LDO2 can work in tracking or de-tracking modes:
   • Tracking mode: Place a jumper on JP4. Place a jumper on JP15: Position 1-2 to make LDO2 track an external LDO. Position 5-6 to make LDO2 track LDO1.
   • De-tracking mode: If present, remove the jumper from JP4. Place a jumper on JP15 in positions 3-4.
5. To make the LDO2 shut down in case of LDO1 thermal shut down, remove a jumper on JP5.

Test results

The figures below show an example of Enable transaction from the high level to the low level and back to the high level (blue arrows). When EN1,2 goes low (GND), VO1,2 = 0 V.

The images below show the reset signal of VO1 and VO2 without watchdog activated, considering two different voltage levels.

The following figures show examples of thermal warning and thermal shutdown, with an ambient temperature of 23.5°C and an operating voltage of 5 V.

Schematic diagrams

The document includes detailed schematic diagrams for the AEK-POW-LDOV02X evaluation board, illustrating the circuit design and component connections.

Bill of materials

The bill of materials lists all the components used in the AEK-POW-LDOV02X evaluation board, including their part numbers, quantities, and manufacturers.

Board versions

Information regarding different versions of the AEK-POW-LDOV02X evaluation board is provided, including references to schematic diagrams and bills of materials.

Regulatory compliance information

This section provides important regulatory compliance information, including notices for the US Federal Communication Commission (FCC), Innovation, Science and Economic Development Canada (ISED), the European Union, and the United Kingdom. It details compliance with directives such as EMC and RoHS II.

Revision history

The document revision history tracks changes made to the manual, including the initial release and subsequent updates.

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