Features

Provide SO-8 packaging that saves space

output current: 100mA ( lt1054 )

125 mia ( LT1054L)

Regulate the benchmark and error amplifier

Low loss: 1.1V at 100mA

Running range: 3.5V to 15 volts (LT1054)

] 3.5 volts to 7 volts (LT1054L)

External shutdown

External oscillator synchronization

Pacific connection

and LTC #174; compatible pins;

1044/LTC7660 Type

Application

voltage inverter

Voltage regulator

Negative voltage multiplier

[ 123] Positive voltage multiplier

Description

lt #174; 1054 is a single -chip bipolar switch capacitor voltage converter and regulator. The LT1054 offer output current is significantly reduced than the previously available converter voltage loss. The adaptive switch driver scheme optimizes efficiency output current within a wide range. The total voltage loss in the 100mA output current is usually 1.1V. Under the entire power supply voltage, this range is 3.5V to 15V. Static current is usually 2.5mA. The LT1054 also provides a regulatory function, which is a function that did not have before the switch capacitor voltage converter. It can be obtained by adding an external resistor division to adjust the output. The output will change according to the input voltage and output current. This LT1054 can also be closed by ground feedback. The power current is less than 100 μA during the stop. The internal oscillator of the LT1054 runs at a rated frequency of 25kHz. The oscillator pins can be used to regulate the switch frequency or the external synchronization LT1054. LT1054 is compatible with previous converters such as LTC1044/LTC7660.

absolute value

Power voltage (Note 2)

LT1054 16 伏

LT1054L 7 volts

Input voltage

needle 1 0V ≤Vpin1 ≤V+

pin 3 (s packag 123]

pin 13 (S package) in10vref≤vp3

Working temperature range

LT1054C/LT1054LC 0 ° C 0 ° CTo 100 ° C

LT1054I – 40 ° C to 100 ° C

Most Temperature (Note 3)

LT1054C/LT1054LC 125 degrees Celsius

LT1054i 125 degrees Celsius

Storage temperature range

J8, N8, and S8 packages –55 ° C to 150 ° C

S packaging –65 ° C to 150 ° C

Lead temperature (welding, 10 seconds) 300 degrees Celsius

The electrical characteristics indicate the specification for the entire operation

The temperature range, otherwise the specification is TA 25 ° C. (Note 7)

Note 1: The absolute maximum rated value means that the value device that exceeds life may be damaged.

Note 2: 16V's absolute maximum power supply voltage rated value is applicable to non -regulating circuits of LT1054. For the regulating mode circuit, when using the VOUT ≤ 15V of the LT1054 and the pins 5 (pin 11 on S), the rated value can be increased to 20V. The absolute maximum power supply voltage of the LT1054L is 7 volts.

Note 3: The design of the device ensures that its function reaches the absolute maximum temperature.

Note 4: For the voltage loss test, the device is used as a voltage connection inverter, and the pins 1, 6 and 7 (3, 12, and 13S packaging) are not connected. In other configurations, voltage loss may be higher.

Note 5: The output resistance is defined as the curve slope ( #8710; vout vs #8710; IOUT), and the output current is 10mA to 100mA. This means part of a linear curve. The incremental slope of the curve will be at the characteristics of the switching transistor, current lt; 10mA.

Note 6: All specifications are suitable for connection to positive-negative converters/regulators, R1 20K, R2 102.5K, C1 0.002 μF, (C1 0.05 μF S packaging) CIN 10 μF , COUT 100 μF 钽.

Note 7: S8 packaging uses mold packaging different from H, J8, N8, and S. The S8 device will meet all existing data table parameters. See the adjustment part of the adjustment and capacitor selection in the application information.

Typical performance features

pin function

fb/shdn (pin 1) : Feedback/shutdown pin. This other needle has two functions. Selling 1 below the shutdown threshold (≈0.45V) to stop the device. When closed, the reference/regulator is turned off and the switch stops. The settings of this switch enable both CIN and COUT can be loaded through the outputCharging. The static current input is about 100 μ performance characteristics). Any open setting door can be used to close the LT1054. Normally (not adjusted) operation should be closed when the outer doors are closed. In the LT1054 circuit, using the adjustment function, the external resistor division can provide sufficient drop -down power to keep the device shut down until the output capacitor (COUT) is completely discharged. For most people, the LT1054 intermittent operation application is not a problem, because the discharge time is shorter than the interruption time of the device. Before the device must discharge the capacitor (COUT), it must be at the LT1054. With the circuit in Figure 5, the restart signal can be the pulse (TP GT; 100 μs) or high logic. The re -startup signal of the diode coupling input needle pin 1 will allow the output voltage to adjust, and do not adjust it. The resistor should select the separator R3/R4 in Figure 5 to provide the signal level of the needle 1 of the needle 0.7V to 1.1V. Point 1 is also an incorrect reverse input amplifier for LT1054, so it can be used to obtain output voltage.

CAP+/CAP- (pin 2/pin 4): pin 2, orthopedic input capacitor (CIN) in V+and ground. When driving to V+, the pins 2 get the current from V+. When driving to ground, the needle 2 remits the current to the ground. Do not need to drive the negative side of the capacitor and drive between the ground voltage alternately. When the car drives to the ground, the needle 4 remits the current to the ground. When driving to the valve feet 4, the current source from Kut. The current flow switch under all cases is one -way bipolar switch.

VOUT (pin 5): In addition to being used as an output pin, the pin is also tied to the substrate of the device. It is necessary to be careful in the LT1054 circuit to avoid pulling out any other pins of the pin. Coming out of the campaign 3 (GND) is a substrate diode that will prevent the device from starting. When the output load is LT1054 refers to its positive power supply (or other power supply positive voltage). Note that most operational amplifiers are such loads because their power currents from V+terminals to V terminals. In order to prevent the startup problem of such loads, the external transistor must be added as shown in Figure 1. This will prevent VOUT (pin 5)

pin function

from being pulled to ground needle (needle 3). Any small general -purpose transistor can use 2N2222 or 2N2219. The RX should be selected to provide sufficient base drives for the external transistor in order to be output voltage and maximum output current conditions in the rated output voltage. In some cases, the N -channel enhanced MOSFET can be used to replace the transistor.

VREF (pin 6): Reference output. The pin provides a 2.5V voltage for reference point for the regulator circuit based on the LT1054. The temperature coefficient of the reference voltage has been adjusted to make the voltage voltage output voltage connectNearly zero. This requires a refer to the output with a positive temperature coefficient from a typical performance curve. This non -zero drift is to offset the internal reference allocation and comparator network connection to the feeder foot. The overall result of these drift items is a regulatory output. When the output voltage is lower than 5V, its temperature coefficient is slightly positive, and the output voltage is negative TC when the output voltage is higher than 5V. For the reference output, the current should be limited to about 60 μA for the regulator feedback network. The reference needle will be 对100 μA when the ground is short -circuited, which will not affect the internal benchmark/regulator. Therefore, the pin can also be used to pull the LT1054 circuit that needs to be synchronized.

OSC (pin 7): oscillator pin. This sales can be used to increase or reduce the frequency of oscillator or make the device synchronize an external clock. The internal needle pin 7 is connected to the time capacitor (CT≈150PF) to the oscillator, and alternately charges and discharge through the current source of ± 7 μA, so as to occupy 50%of the duty ratio. The LT1054 oscillator is designed to minimize the switch loss in the switch. However, the frequency can be improved, decreased, or synchronized with the external system clock (if necessary). The frequency can be used to add a capacitor from 7 to ground (C1, Figure 2) from the outer pin. This will increase the number of charging and discharge, reducing the frequency of oscillator. The frequency can increase the addition of external capacitors (C2, Figure 2, range 5pf to 20pf), from 2 to pinnal pin 7. This capacitor couples to charging to CT during the switch, which will shorten the charge and discharge time and increase the frequency of the oscillator. Synchronization can pull it from the external resistance from the pin 7 to the external resistance of the pin (pin 6). It is recommended to pull 20K. The open range can then use a gate or NPN transistor to drive the oscillator pins at the external clock frequency, as shown in the middle. It is not recommended to pull the needle 7 to the external voltage. For circuits that need to be synchronized and adjusted frequently, external reference can be used as R1/R2 division, and pins 6 is allowed to be used as a pull point 7.

V+(pin 8): Enter the power supply. LT1054 is charged alternately when CIN and the input power supply, and then transfer the charge to Coutcin to switch parallel with COUT. Switch occurs at the frequency of oscillator. During CIN charging, the peak power current is about 2.2 times the output current. The power supply current dropped to about 0.2 times the output current. The input power bypass capacitor will provide some peak inputs from the current of the LT1054, and find the average value of the current to extract from the supply. The minimum input power bypass is 2 μF capacitors, preferably or other low -recommended use of ESR types. The larger capacitor may be in some cases, for example, when the actual input power supply is connected to the LT1054 through the long lead, or when the pulse current generated by the LT1054 is connected to other circuits of the power supply coupling.

Application information

Operation theory

In order to understand the working principle of LT1054, a basic switch capacitor blocks are helpful. In Figure 3, when the switch is on the left side, the capacitorThe device C1 will charging to the voltage V1. The total cost of C1 is q1 C1v1. Then switch to the right, discharge C1 to voltage V2. After the discharge time, the charge on C1 is Q2 C1V2. Please note that the cost has been from the source V1 to the output V2. The amount of the charging amount is: #8710; q q1 -q2 C1 (V1 – V2) If the switch is circulated F times per second, the transmission of the charging unit time (that is, current) is: ( #8710; q f ) [1 (F)] In order to obtain an equivalent resistance of the switch capacitor network, we can use voltage to rewrite the equivalent effect of this equation:

Define a new variable requit, Requiv 1/FC1. Therefore, the equivalent circuit network of the switch capacitor is shown in Figure 4. LT1054 also has the same function switching action as the basic component of the switch capacitor. Even if this simplification does not include limited connection resistance and output voltage ripples, it provides an intuitive feeling of how to work in the device. These simplified circuits interpret the voltage loss as a function frequency (see typical performance characteristics). As a lower frequency, the output impedance will be

controlled by 1/FC1 item. The voltage loss will stand up. Please note that as the frequency increases, loss will increase. This is caused by internal switch loss caused by losses in each switch cycle. The charging loss per unit cycle is used as a current loss by switching frequency. The loss of high frequency becomes significant, and the voltage loss rises again. The oscillator of the LT1054 is designed to be the smallest frequency band in voltage loss.

Regulations

The error amplifier of the LT1054 puts the driver servo to the PNP switch to control the voltage on the input capacitor (CIN), and then determines the output voltage. The exterior resistor division of the use and error amplifier of the LT1054 is set to set the adjustment output voltage. Figure 5 shows the proper resistance value of the basic regulator configuration and calculation formula. Select R1

20K or higher, because the reference output current is limited to ≈100 μA. R2 should choose between 100K and 300K within this range. In order to get the best results, the ratio of CIN/COUT is 1/10. C1, the adjustment of the light load current required for a good load should be 0.002μF output voltage. A new mold layout is needed to adapt to the size of the physical environment S8 component. Although the new death LT1054CS8 will meet the existing LT1054 product introduction, the subtle differences of the layout need to consider new molds in certain application circuits. The nominal value of the capacitor in the adjustment mode of the 1054CS8 regulatory mode must be about the correct operation temperature on the elevation. This is different from the previous part. The non -matching container within the normal production tolerance range is acceptable. Make the nominal capacitance value equal to ensure that it is improving the knot temperatureThe cost is the degradation of the transient response of the regulator circuit. For non -regulating circuits, the values u200bu200bof CIN and COUT are usually equal for all packages. For the assistance of the S8 application special application circuit, please consult the factory. From the circuit frame diagram, it can be seen that the maximum adjustment output voltage is limited by the power supply. For basic configuration, | Vout | Refers to the ground needle of the LT1054 less than the voltage loss caused by the power supply voltage. The relationship between voltage loss and output current caused by switches can be found in typical performance characteristics. The configuration of other negative multiples can provide higher output voltage when the output current is reduced (see typical applications).

Capacitor selection

For non -regulating circuits, the nominal value of CIN and COUT should be equal. For regulatory circuits, see regulations. The accuracy of CIN and COUT is non -critical, good quality, and low ESR capacitors, such as solid state, to minimize voltage loss at high current. For CIN, the ESR effect of the capacitor will lose due to twice the switch current as about twice the output current in the charging and discharge cycle. This means that the effect of using ESR to 1 #8486; CIN is the same as the effect of increasing the output impedance of LT1054 by 4 #8486; This means increased voltage loss. Because the impact of blood sink is not so dramatic. COUT is an ESR of an ESR of an output current electric container alternating and discharging the power container. This step will reduce the output load current. Realizing that the price of large -capacity pyrades is expensive, a large -scale aluminum electrolytic capacitor can be used to use large aluminum electrolytic capacitors that can be used for parallel to smaller 钽 to obtain low ESR and reasonable costs. Where is the problem of some new chip types that can be used to use a capacitor. These capacitors usually have a rated operating voltage between 10V and 20V and displayed very low ESRs (within the range of 0.1 #8486; range).

Output ripple

Peak to peak output ripples determine the output capacitor and output current by this value. The peak peak output ripples can be approximately similar to the following formulas:

In the formula, DV peak ripple, F oscillator frequency. For output capacitors with significant ESR, the second item must be added to explain the voltage level of the switch. This step is about equal to: (2 outputs) (ESR of COUT)

Power loss

The power consumption of any LT1054 circuit must limit the temperature of the device to the maximum temperature range. The total power consumption must be based on the two components, the power loss caused by the power loss switch and the driving current loss caused by the decreased voltage. The total power consumed by LT1054 can be calculated: p≈ (vin - | vout |) (input)+(vin) (input) (input) (0.2) (0.2) Among them, VIN and VOUT pointed to the ground needle (pin 3) LT1054. For the LT1054 regulator circuit, the dispersion of the power supply will be equivalent to the linear regulator. Due to the limited power processing capacity of the LT1054, the user must limit the output current requirements or take measures to dissipate the external power supply LT1054 for large input/output gigitation. This may be realized by connecting the resistor and CIN series as shown in Figure 6. Part of the input voltage will pass through this resistor without affecting the output. Because the switching current is about 2.2 multiplied by a voltage drop at a resistor CIN charging and discharging, the resistor should be selected as:

IOUT the maximum output current required for iOut Essence Factors 1.3 will provide some operating profits for LT1054. For example: assuming that there is an output current of 12 to 5 volts at 100 mAh. First calculate the power consumption when there is no external resistance: P (12 volts - | - 5 volts |) (100 mAh)+(12 volts) (100 mAh) (0.2) p 700mW+240mW 940MW at 130 ° at 130 ° at 130 ° Under the θja of C/W, the commercial plastic device will cause the knot temperature to increase by 122 ° C. Therefore, when the ambient temperature is 25 ° C, the device will exceed the highest knot temperature. Calculate the power consumption with an external resistor (RX). How much voltage can be reduced on RX for the first time. The maximum voltage loss of the LT1054 in the standard stabilizer is 100mA output current is 1.6V, so VX 12V - [(1.6V) (1.3)+| --5V |] 4.9V and RX 4.9V/(4.4) (100mA) 11 #8486; This resistor will reduce the LT1054 multiplier (4.9V) (100mA) 490MW. The dissipation volume of the total power LT1054 is (940MW – 490MW) 450 MW. The rising temperature is now only 58 ° C. Although the commercial equipment guarantees that the normal work at the knot temperature only guarantees that the knot temperature of 125 ° C is 100 ° C, the ideal of the knot temperature should be 100 ° C ideal under the ideal circumstances. For the above example, this means that the ambient temperature is limited to 42 ° C. You can take other steps to allow higher environmental temperatures. The thermal resistance packaging of LT1054 represents the sinking and static air without heating. Small clamping radiator can be used to reduce thermal resistance of the LT1054 component. In some systems, there may be some available airflows that will help reduce thermal resistance. The circuit board traces of the wide PCLT1054 wire also help discharge calories from the device. Especially for plastic packaging.