LP2950 and LP2951 are specially designed by micro-power pressure regulator to maintain properly adjusting low input-output voltage differences. The characteristics of these devices are that the low static bias current is 75 A, which can provide an output current exceeding 100 mAh. Internal current and heat provide restrictions and protection. LP2951 has three additional functions. The first is an error output, which can be used to send signal adjustment conditions to the external circuit to the output, or use it as a microprocessor to power and reset. This second function allows the output voltage to preset at 5.0 V, 3.3 V, or 3.0 V output (depending on the model) or from 1.25 V programming it includes a fixed resistor divisor and DC electrical access error amplifier feedback input. The third feature is the output of the processed input regulator that allows the logic level signal to be turned off or connected. Due to the low input-output voltage difference and bias current specifications, these devices are the ideal life of computer, consumer goods and industrial equipment batteries for battery power supply. LP2950 has three types of model pink shells 29 and DPAK packaging. LP2951 can be installed and packaged on the eight-pin dual-column, SOIC-8 and Micro8 surface. The A suffix has an initial output voltage tolerance ± 0.5%.

Features

75 A's low static bias current #61623; 100 A's low input output voltage difference is 50 mv, and 100 mAh is 380 millivoltors [ 123]

5.0 V、3.3 V或3.0 V±0.5%允许用作调节器或参考

极为严格的线路和负荷调节

仅需1.0 F输出电容器以Maintain stability

Internal current and thermal limit

NCV prefix, used to need

unique on -site and control change requirements; AEC q100

] Qualified and PPAP capabilities

These devices are not lead, in line with the ROHS standard

LP2951 additional function

Error output signal is irregular state

1.25 V v To 29 V's programmable output

Logic level off input

Maximum rated value (TA 25 ° C, unless otherwise instructions)

The stress that exceeds the maximum rated value may damage the device. The maximum rated value is only the stress rated value. The above function operation does not imply the proposed operating conditions. Under the stress that exposed long -term exposure to the recommended operating conditions may affect the reliability of the equipment

Electrical characteristics

(vin vo+1.0 v, IO 100 A, CO 1.0 F 1.0 f TA 25 #61616; C [Note 3], unless there is another instructions. )

1. As shown in Figure 29, the thermal resistance of the paired environment is determined by the PCB copper area.

2. This series of equipment includes ESD protection and exceeds the following tests:

Human model (HBM), 2000 V, level 2, JESD22 A114-C

Machine model (MM), 200 V, B, BESD22 A115-A

Charging Equipment Model (CDM), 2000 V, IV level, JESD22 C101 Pulse technology is used to keep the knot temperature as close to the ambient temperature during testing.

4.vo (nom) is the part number option.

5. When performing noise testing on LP2951, use a 0.01 F capacitor to connect to the pin 7 and 1.

*NCV prefix is used for automotive and other applications that need to be controlled by sites and changes.

Electric characteristics (continued)

(vin vo+1.0 v, IO 100 A, CO 1.0 f, TA 25 #61616; c [Note 8], unless it is unless Another explanation.

6. As shown in Figure 29, the thermal resistance of the paired environment is determined by the PCB copper area. ESD data.

8. Low -occupying ratio pulse technology is used to keep the knot temperature as close to the ambient temperature during the test.

9.VO (NOM) is the partial voltage option.

10. When performing noise testing on LP2951, use a 0.01 F capacitor to connect between the pin 7 and 1. Application.

Voltage drop-input/output voltage difference

At this time, the regulator output no longer keeps adjusting to prevent the input voltage from further decrease. The measurement time output voltage is lower than its nominal value 100 100 MV (that is, measured at 1.0 V different), it will affect the supply voltage, load current, and minimum input supply requirements. Line adjustment A output voltage changes in input voltage changes. The measurement is based on low loss or use. The condition of the pulse technology does not significantly affect the average temperature of the chip. The output voltage of the load adjustment a changes to the constant chip temperature down the load current. Within specifications. Bias current-for operating pressure regulator chips, not transported to the load. Output noise voltage output, constant load, no input ripple, measurement within the specified frequency range. Leakage current-The hagement voltage at the time of the bipolar transistor set electrode base tube is off . The upper limit voltage-applied to the comparator input terminal, which is lower than the reference voltage to the other comparator input terminal, causing the comparator output from logic 0 to 1 . The lower threshold voltage-applied to the comparator input terminal, which is lower than the reference voltage application to another comparator input terminal, causing the comparator output from the logic 1 to 0 . Different voltage and upper limit voltage between lag-lower threshold.

Introduction Turn off with heat to make them user -friendly. LP2950's typical application circuit LP2951 is shown in Figure 20 to 28. These regulators do not have internal compensation, so 1.0 F (or larger) capacitance LP2950/LP2951 output terminals and stable grounding. Most types of aluminum, 型 or multi -layered ceramics will fully play a role. Solid or proper multi -layer ceramic capacitors are recommended to run below 25 ° C. The smaller the output current, the smaller the output capacitor is necessary for the output stability. The capacitor can reduce the current of 0.33 F when the current is less than 10 mA, and the current is 0.1 F below 1.0 mAh. In the voltage below 5.0 V, it is placed in a large increase value operation error, so more output capacitors are needed to maintain stability. For the worst operating situation output of 100 MA loads under 1.23 V (connected to feedback pin 7) A is recommended to be 3.3 F. When the output load is running. When setting output, the voltage with an external resistor with an external resistor. The selection of the resistance to the minimum value of 1.0 A should be selected. It is recommended to enter the ground in LP2950/LP2951. If more than a 4 -inch wire, the input is connected to the battery or power filter capacitor. LP2951 feedback needle 7 can input capacitance to generate a pole. If the external value is high, it will cause unstable resistance to set the output voltage. Add a capacitor between 100 PF output needle 1 and feedback pin 7 and increase the output filter capacitance to at least 3.3 F to a stable feedback circuit.

error detection comparator

No matter when, the comparator will switch to positive logic low level LP2951 output voltage by more than 5.0%exceeding the regulations. This value is the design compensation voltage of the 60 MV of the comparator. As shown in the representative block. The check -in level is still lower than the normal value of 5.0%regardless of the value of the regulating output voltage. For example, for the normal 5.0 V, the wrong sign of the wrong sign is 4.75 V to adjust the output, or 9.50 volts, and the output voltage of 10 volts. Figure 2 shows the wrong timing chart signal andThe adjustment output voltage is tilted up and down as the input voltage to LP2951. The error signal becomes effective (low) when input of about 1.3 V. When the input reaches about 5.0 V (Vout exceeds about 4.75 V). Because the lower voltage of LP2951 depends on the load current (refer to the curve characteristics in the typical performance), the input voltage checkpoint will be the load current. The output voltage trigger point does not change the load. The output of the error comparator is that an outer pull -up resistor needs to be opened. This resistor may return to the output or system. The resistance value should be selected as a consistent comparison with the 400 A receiver capacity. The values between 100 k and 1.0 m are recommended. If the output is unused. When running in the shutdown mode, the error is pulled to the external supply if the comparator output is pulled. In order to avoid this invalid response, the error should be pulled to VOUT (see Figure 18)

Output voltage programming (LP2951)

LP2951CX can be used The fixed output voltage of the internal pressure is connected to the needle 1 (output) to the pinna (induction) and the needle pin 7 (feedback) to the pin 6 (5.0 V section). Alternatively, it can be programmed at 1.235 reference voltage and its maximum rated voltage to 30 V. A pair of external resistors are shown in Figure 19.

The complete equation of the output voltage is:

Among them, VREF is the nominal voltage, and the VREF is the reference voltage is the feedback pin bias current current , Nominal 20 na. The minimum load current of this proposal is 1.0 A. If the regulator must be carried out. IFB will generate a typical error of 2%at room temperature by adjusting R1. In order to obtain better accuracy, select R2 100K while increasing the resistance, reduce the error to 0.17%, and program programming to 12 ampel. Because LP2951 is usually 75 A empty load, pins 2 openings, the consumption of additional 12 A current is usually worth a weighing. There is no need to set the output voltage in the test.

Output noise

In many applications, reducing noise appeared on the output end. Reducing the bandwidth of the regulator to increase the size of the output capacitor is the only method to reduce the noise on the 3 -line LP2950. However, when the capacitor is only increased from 1.0 F to 220 F at 100 kHz, the noise is reduced from 430 volts to 160 volt 5.0V output bandwidth. By bypass electrical containers, noise can be reduced by R1 by four times, because it will high -frequency gain from 4 to unite.

or about 0.01 F. When performing this operation, the output capacitor must be increased to 3.3 f to maintain stability. These changes reduce output noise from 430 voltsBy 126 volt 5.0V output is 100 kHz bandwidth.With bypass and capacitors, the noise no longer changes with the output voltage. Therefore, when the output is higher, the improvement is more significant.

All diodes are 1N4148.Low input voltage warning signs.

Under a lower input voltage, the main output is locked.

Spare battery with auxiliary output.

Operation: The VOUT programming of the regulator 1 is reduced to 5.0 V.When the error logo becomes activated, when the vehicle recognition number (VIN) is less than 5.7 volts, when the vehicle identification number (VIN) drops to 5.3 volt below 5.3, the error sign of the regulator 2 is activated and locks the main output level through Q1.When Vin exceeds 5.7 V again, the regulator 1 resume adjustment, and the warning signal rises, unlock the regulator 2

Voltage 1.25V (1.0+R1/R2)

For 5.0 V output, use internal resistors.Site 6 to 7, and connect the needle 2 to the+VOUT bus.