Features

● Green idle power saving mode

A single 2.7V to 3.6V power supply

] ●

Use 3V logic operation

●

0.1 μF to 1 μF charge pump capacitor

● Low electromagnetic interference

] ●

Low-power shutdown: 20 na

●

fully meets RS-232

● 460 kb/s data data Rate

● A receiver is in a closed state (ADM3307E/ADM3311e/ADM3312e/ADM3315E)

● The two receivers are in a closed state ( ADM3310E)

● ESD-232-2 operating system gt; 1000 kV

● ESD GT on CMOS and RS-232 I/O ; 15 KV IEC 1000-4-2 (ADM3307E)

● Suitable for car applications

Data cable

● Notebook computer and laptop computer

Printer ●

peripheral equipment [ 123]

● modem

● PDA/handheld device/palm computer

Function box diagram

General description The design of the ADM33XXE series driver/receiver products fully meets the EIA-232 standard, while using a single 2.7 V to 3.6 V power supply. The device has a vehicle charge pump DC-DC converter and no dual power supply is required. This DC-DC converter contains a voltage trio and a voltage inverter, which generates positive and negative power supply from the input 3V power supply. The DCTO-DC converter works in the green idle mode. The charge pump oscillator is selected and closed, and the output voltage is kept at ± 7.25V under different load conditions. This will minimize the power consumption and make these products the ideal choice of portable equipment for battery power.

ADM3312E and ADM3315ADM3315ADM331E are suitable for ADM3315ADM331E in harsh environments. ADM3307E contains all I/O lines (CMOS, RS-232, EN, and SD) for all ESDs.

A shutdown facility also provided to reduce the power consumption to 66 Nm. When closing, a receiver keeps activity (the two receivers are in the active state in ADM3310E), which allows monitoring peripheral equipment. This function allows the device until the peripheral device starts to communicate.

Activity receiver can send alarm to the processor, and then the processor can withdraw the ADM33XXE device withdraw from the closure mode.

ADM3307E contains five drivers and three receivers for mobile phone data block cables and portable computing applications.

ADM3311E contains three drivers and five receivers for serial port applications on laptop/laptop computers.

The current closure mode of the two ADM331E of ADM331E also allows two ADM331E to be in active.

ADM3312E contains three drivers and three receivers, which are suitable for serial port applications, PDA, mobile phone data block cables and other handheld devices.

The input resistance of the 331E driver of ADM is 331E, which reduces the input resistance of ADME. Its main application is PDA, palm computer, and mobile phone data packet cables.

ADM33XXE device is made of CMOS technology, with the least power consumption. All components have high levels of overvoltage protection and locking resistance.

All ADM33XXE devices offer 32 lead 5 mm × 5 mmLFCSP WQ and TSSOP (28 -leading ADM3307E, ADM3310E, and ADM3311e; 24 -commanded ADM3312E and ADM3315E in TSSOP). ADM3311E also has 28 lines of SSOP.

ADM33XXE device is a reinforced RS-232 line drive/receiver, which can be powered by a single power supply from 2.7 V to 3.6 V. Based on the voltage converter and the level conversion transmitter and the receiver, the RS-232 level is allowed to develop the RS-232 level during the operation of a single power supply. Features include low power consumption, green idle operation, high transmission rate, and compatibility with EU electromagnetic compatibility instructions. This electromagnetic compatibility instruction includes protection of radiation and conduction interference, including high -level static discharge.

All RS-232 (and CMOS, SD, EN for ADM3307E) input and input and inputEach is protected by static discharge (up to ± 15 kV). This ensures that IEC 1000-4-2 requirements.

These devices are very suitable for working in a harsh electrical environment or RS-232 cables often work in environments. They are also immune to high frequency fields and do not need special protection measures.

The emissions are also controlled in a very strict range. CMOS technology is used to maintain the minimum power consumption, allowing the maximum battery life to be portable.

Typical performance characteristics

Circuit description The internal circuits are mainly four parts of the four parts. composition. This includes the following: charge pump voltage converter

EIA-232 transmitter 3.3 V logic

EIA-232 to 3.3 V logical receiver

all I/O lines on the transient protection circuit

Charging pump DC-DC voltage converter

The charge pump voltage converter consists of 250 kHz (ADM3307E is 300 kHz) oscillator and switch matrix. The converter generates ± 9 V power from the input 3.0 V level. This is completed through two stages through switching capacitance technology. First, use the capacitor C4 as the charge storage element, and increase the 3.0V input power supply three times to 9.0V. Then, using C5 as a storage element, the +9.0 V level reverse the +9.0 V to generate #8722; 9.0 V.

However, it is important to note that, unlike other charge pump DCTO DC converters, the charge pump on the ADM3307E does not open the loop. The output voltage is adjusted to ± 7.25 V through the green idle circuit (for ADM3310E and ADM3315E to ± 6.5 V), and it has never reached ± 9 V. This not only saves electricity, but also maintains a more constant output voltage.

The three -link work is divided into two stages. When the oscillator is low, S1 and S2 are closed, and C1 is quickly charged to VCC. S3, S4 and S5 are opened, S6 and S7 are closed.

When the oscillator is high, S1 and S2 are disconnected, S3 and S4 are closed, so the output voltage of S3 is 2VCC. This voltage is used to charge C2. Without any discharge current, C2 is charged to 2VCC after several cycles. During the high phase of the oscillator, as mentioned earlier, the S6 and S7 are closed, so the output voltage of the S6 is 3VCC. The voltage was then used to charge C3. The voltage is shown in Figure 25.

During the high phase of the oscillator, S10 and S11 opened, and S8 and S9 closed. In several cycles, C3 charged from the output end of the voltage three times to 3VCC. During the low phase of the oscillator, the S8 and S9 opened, and the S10 and S11 were closed. C3 cross -C5 is connected, its positive extremes are grounded, and the negative polar terminal is V output. In several cycles, C5 is charged to #8722; 3 VCC.

If the current requirements are small, the V+and V-power supply can also be used to power the external circuit. See Figure 12 of the typical performance feature part.

What is green idle?

Green and idle is a method that minimizes power consumption under the condition of free (no transmission), while still maintaining the real -time transmission capacity of data.

How did it work?

The charged pump DC-DC converter used in the RS-232 line drive is usually opened by the loop, that is, the output voltage is not adjusted by any way. Under the light load conditions, the output voltage of the frequency frequency device is nearly twice the power supply voltage. The output voltage of the three times frequencyr is three times the power supply voltage, and the ripples are very small. As the output voltage decreases, the ripples increase.

Even under the air load conditions, the oscillator and charge pump work at a very high frequency, resulting in switching loss and current loss.

Green idle speed work by monitoring the output voltage and keeping it at a constant value of about 7V (1). When the voltage rises to 7.25 V (2), the oscillator is closed. When the voltage drops below 7 V1, the oscillator is opened and a charging pulse is sent to the storage tank capacitor. In the case of zero load, the average power consumption of the light pump was almost cut off.

(1), for ADM3310E and ADM3315E, replaced to 6.5 V.

(2), for ADM3310E and ADM3315E, replaced to 6.25 V.

The frame diagram of the green idle circuit is shown in Figure 26. Monitor V+and V-and compare it with the reference voltage of the gap device from the chip. If V+or V-below 7 V (1), the oscillator will start until the voltage rises to 7.25 V (2).

FIG. 27 shows the green idle operation of V+under various load conditions. Under light load conditions, C1 is kept in charging, and only one oscillator pulse can be charged to charger C2. In this case, V+may actually exceed 7.25V (2).

Under medium load conditions, C2 is charged to 7.25 v (2) It may take several cycles. The average frequency of the oscillator is higher, because there are more pulses in each pulse group, and the distance between the pulse group is closer and the frequencyhigher.

Under high load conditions, if the output of the charge pump cannot reach 7.25 v (2), the oscillator will continue to open.

Green idle speed and shutdown

The shutdown mode is to minimize power consumption by completely closing the charge pump. In this mode, the switch configuration in the voltage three -twice device is connected to VCC directly. V #8722; Zero, because there is no oil supply pump operation to fill the C5. This means that before the V+and V-reaches its normal operating voltage, there will be a delay when exiting the shutdown mode. Green idle keeps the transmitter's power voltage under the idle state of the transmitter, so this delay will not occur.

Does green idle increase the power supply ripple?

The ripple of the output voltage of the charged pump on the loop of the loop depends on the three factors: the frequency of the oscillator, the capacity of the energy storage device, and the load current. The value of the storage tank capacitor is fixed. Increase the frequency of the oscillator to reduce the ripple voltage; reduce the frequency of the oscillator to increase the ripple voltage. Increasing the load current increases the ripple voltage, and reducing the load current will reduce the ripple voltage. The ripple voltage under the lighted load is naturally lower than the ripple voltage under the high load current.

When using green idle speed, the ripple voltage is determined by the high and low threshold of the green idle speed. These voltages are usually 7V (1) and 7.25V (2), so under most load conditions, the ripples are 250 MV. Under very light load conditions, there may be more than 7.25V (2) over -transfer, so the ripples will be slightly larger. Under high load conditions, the output will never reach 7.25V (2). The green idle circuit does not work. The ripple voltage is determined by the load current, which is the same as the situation in the ordinary charge pump.

What about electromagnetic compatibility?

The green idle speed cannot work at the frequency of constant oscillator. Therefore, the frequency and spectrum of the oscillator signal change with the load. Any radiation and conduction emitter will change accordingly. Like other simulated equipment RS-232 transceiver products, the ADM33XXE device has a conversion rate limit and other technologies to minimize radiation and transmission emission.

(1), for ADM3310E and ADM3315E, replaced to 6.5 V.

(2), for ADM3310E and ADM3315E, replaced to 6.25 V.

The transmitter (drive) part

The driver converts the 3.3V logic input level to the EIA-232 output level. When VCC u003d 3.0 V and drives the EIA-232 load, the output voltage swing is usually ± 6.4 V (or ADM3310e and ADM3315E as ± 5.5 V).

Unused inputs can be kept discontinuous, because the internal 400kV pull -up resistance raised them to force them to enter a low state. GroundAt the time, the power supply of the upper pull -up resistor is usually 8 mAh, so the input that is not used should be connected to V or kept disconnected to minimize the power consumption.

The receiving section

The receiver is the reversing level displacement, accepts the RS-232 input level and converts it to 3.3V logical output level. The input terminal has a 5 kΩ internal drop -down resistor (ADM3310E is 22 kΩ) grounding, and it can prevent overvoltage of up to ± 30 V. The unconnected input end is pulled down from the internal 5 kΩ (or ADM3315E to 22 kΩ) to 0 V. Therefore, for the input or connected to the GND, this will lead to logical 1 output level.

The receiver has a Schmidt trigger input with a lagging level of 0.14V. This ensures no error receipt of noise input and slow conversion time input.

Enable and close

The enable function is designed to promote the data bus connection, which requires the output of a receiver with three states. In the disable mode, all receiver output is in a high impedance state. The shutdown function is to turn off the device to minimize static current. In the state of stopping, all transmitters are disabled. Turn off all the receiver, the receiver R3 (ADM3307E, ADM3312E, and ADM3315E), the receiver R5 (ADM3311E), and the receiver R4 and the receiver R5 (ADM3310E). Note that the disabled transmitter is not three states in the shutdown state, so multiple (RS-232) drives are allowed to be connected together.

The shutdown function is very useful in the battery power supply system because it reduces power consumption to 66 Nm. During the shutdown, the oil supply pump will also be discontinued. After exiting the suspension, the charge pump is restarted, and about 100 μs is required to meet its steady -state operating conditions.

High Potter rate

ADM33XXE has a high conversion rate, allowing the data transmission rate to far exceed the EIA/RS-232E specification. Under the worst load conditions, the RS-232 voltage level remains at a data rate of up to 230 Kbps (ADM3307E for 460 KBPS). This allows high -speed data links between two terminals. Layout and supply decoupling

Because the operating frequency of the ADM33XXE oscillator is very high, special attention should be paid to the layout of the printing circuit board. All records should be as short as possible. As far as possible to connect to the device. It is strongly recommended to use ground layers below and around the device.

When the oscillator is started during the green idle operation, the VCC will produce large -current veins. Therefore, VCC should be decoupled with parallel combination of 10 μF 钽 钽 and 0.1 μF ceramic capacitors, and as close to VCC quotes as much as possibleFoot installation.

The values u200bu200bof capacitor C1 to capacitor C3 are between 0.1 μF and 1μF. The larger the value, the smaller the ripple. These capacitors can be electrolytic capacitors for low -equation series resistors (ESR) or non -polar capacitors, but it is strongly recommended to use ceramic types. If the polarized electroacapacitator is used, the polarity must be observed (such as C1+).

ESD/EFT transient protection scheme

ADM33XXE uses a protective clamp structure on all input and output, stabilizes the voltage to the safe level, and dissipates ESD (electrostatic) and EFT (EFT (static) and EFT (EFT (static) and EFT ( Electric fast transient) energy in discharge. The simplified schematic diagram of the protection structure is shown in Figure 30 and Figure 31 (the ADM3307E protection structure is shown in Figure 32 and 33).

Each input and output contain a high -speed clamp diode with two backs. During the normal working period of the RS-232 signal level, the diode has no effect, because according to the polarity of the signal, one or the other is reverse bias. However, if the voltage exceeds about ± 50 V, reverse breakdown will occur, and the voltage is restrained at this level. The diode is a large P-N knot, which is used to handle the instantaneous current of more than a few ampels.

The output of the transmitter and the receiver input has a similar protection structure. The receiver input can also pass the internal 5 k #8486; (for ADM3310E to 22 k #8486;) resistors and protect the diode, which consumes part of the energy.

ADM3307E protection scheme is slightly different (see Figure 32 and Figure 33). The receiver input, transmitter input and transmitter output contains two high -speed clamping diode with two backs. The receiver output (CMOS output), SD and EN pins, containing a reverse bias high -speed clamp diode. Under the normal work of the maximum CMOS signal level, the receiver output, SD and EN protection diodes have no effect because they are reverse bias. However, if the voltage exceeds about 15 volts, reverse breakdown will occur, and the voltage will be restrained at this level. If the voltage reaches the #8722; 0.7 V, the diode is positive biased, and the voltage is fixed at this level. The receiver input can also consume part of the energy from the internal 5 k #8486; the resistor and protect the diode.

The protective structure achieves ESD protection up to ± 15 kV on all RS-232 I/O lines (and all CMOS lines, including SD and EN of ADM3307E). For the method of testing protection schemes, see the ESD test (IEC 1000-4-2) section.

ESD test (IEC 1000-4-2)

IEC 1000-4-2 (previous 801-2) It specifies the compliance test of the two coupling methods of contact discharge and air gap discharge. Contact discharge needs to be directly connected to the measured unit. The high test voltage is used for air gap discharge, but it does not directly contact the measured unit. In the case of air discharge, the discharge gun was moved towards the measured unit, forming an arc on the air gap, so it was called air discharge. This method is affected by humidity, temperature, atmospheric pressure, distance, and velocity of the shutdown gun. Although the contact discharge method is not realistic, it is more repetitive and easier to be accepted than the gas gap method.

Although the energy contained in the ESD pulse is very small, the extremely high rising time plus the high voltage will cause a non -protective semiconductor to fail. Arcs or heating can immediately cause catastrophic destruction. Even if the disaster failure does not happen immediately, the equipment will degenerate, resulting in a decline in performance. The cumulative effect of continuous exposure will eventually lead to a complete failure.

I/O lines are particularly vulnerable to ESD damage. Simply touching or inserting I/O cables will cause static discharge, which will damage or completely destroy interface products connected to port I/O. The traditional ESD test method, such as the MIL-STD-883B method 3015.7, cannot fully test the sensitivity of the product to this discharge. This test aims to test the sensitivity of electrostatic discharge damage during handling.

Each pin is tested relative to all other pins. There are some important differences between traditional trials and IEC tests.

IEC test is more stringent in discharge energy. The peak current of the injection exceeds 4 times.

in IEC tests, the current rising time is significantly faster.

IEC test was performed when the device was powered on.

ESD discharge may cause the measured device to be atresses. Therefore, the test can represent the real I/O discharge that the device runs normally under power. However, in order to maximize people, these two tests should be carried out to ensure that they can be protected to the greatest extent during the transportation period and the subsequent on -site service period.

ADM33XXE device uses the above two test methods for testing. Test all the pins of the human body according to standard 55.1. In addition, all I/O pins are tested in accordance with the IEC 1000-4-2 test specifications. The product is tested under the following conditions:

Normal operation of power Turn off the power

IEC 1000-4-2 specifies four compliance with four compliances Sexual level. ADM33XXE parts to meet the strictest level of compliance with contact discharge and air gap discharge. This means that the product can withstand more than 8 kilometers of contact discharge and more than 15 kV air gap dischargeEssence

The size of the shape

Automobile product

ADM3307EWModels provide controlled control to support the quality and reliability requirements of automobile applications.Please note that the specifications of this model may be different from commercial models; therefore, designers should read the specifications in the data table carefully.Only automotive -grade products can be used for car applications.Please contact your local simulation equipment customer representatives to obtain specific product ordering information and obtain a specific car reliability report of this model.