M3004LDT

M3004LD REMOTE CONTROL TRANSMITTER FEATURES SUMMARY ■ FLASHED OR MODULATED TRANSMISSION ■ ■ Figure 1. Package 7 SUB-SYSTEM ADDRESSES UP TO 64 COMMANDS PER SUB-SYSTEM ADDRESS HIGH-CURRENT REMOTE OUTPUT AT VDD = 6V (–IOH = 80mA) LOW NUMBER OF ADDITIONAL COMPONENTS KEY RELEASE DETECTION BY TOGGLE BITS VERY LOW STAND-BY CURRENT (< 2µA) OPERATIONAL CURRENT < 1mA AT 6V SUPPLY SUPPLY VOLTAGE RANGE 2 TO 6.5V CERAMIC RESONATOR CONTROLLED FREQUENCY (typ. 450kHz) REMO 1 2 3 4 5 6 7 8 9 10 20 19 ■ ■ ■ SO20 (Plastic Package) ■ ■ ■ ■ Figure 2. Pin Connection VDD DRV 6N DRV 6N DRV 6N DRV 6N DRV 6N DRV 6N DRV 6N OSC OUT OSC IN DESCRIPTION The M3004LD transmitter IC is designed for infrared remote control systems. It has a total of 448 commands which are divided into 7 sub-system groups with 64 commands each. The sub-system code may be selected by a press button, a slider switch or hard wired. The M3004LD generates the pattern for driving the output stage. These patterns are pulse distance coded. The pulses are infrared flashes or modulated. The transmission mode is defined in conjunction with the sub-system address. Modulated pulses allow receivers with narrow-band preamplifiers for improved noise rejection to be used. Flashed pulses require a wide-band preamplifier within the receiver. SEN 6N SEN 5N SEN 4N SEN 3N SEN 2N SEN 1N SEN 0N ADRM VSS 18 17 16 15 14 13 12 11 REV. 2 June 2004 1/14 M3004LD Figure 3. Block Diagram DRV OUTPUTS 0N 1N 2N 3N 4N 5N 6N S E N I N P U T S 0N 1N 2N 3N 4N 5N 6N ADRM VDD VSS OSCI OSCO OSCILLATOR CONTROL LOGIC KEYBOARD SCAN PULSE DISTANCE MODULATOR REMO OUTPUT INPUTS AND OUTPUTS Key matrix inputs and outputs (DRV0N to DRV6N and SEN0N to SEN6N) The transmitter keyboard is arranged as a scanned matrix. The matrix consists of 7 driver outputs and 7 sense inputs as shown in Figure 4. The driver outputs DRV0N to DRV6N are open drain N-channel transistors and they are conductive in the stand-by mode. The 7 sense inputs (SEN0N to SEN6N) enable the generation of 56 command codes. With 2 external diodes all 64 commands are addressable. The sense inputs have P-channel pull-up transistors so that they are HIGH until they are pulled LOW by connecting them to an output via a key depression to initiate a code transmission. ADDRESS MODE INPUT (ADRM) The sub-system address and the transmission mode are defined by connecting the ADRM input to one or more driver outputs (DRV0N to DRV6N) of the key matrix. If more than one driver is connected to ADRM, they must be decoupled by diodes. This allows the definition of seven subsystem addresses as shown in Table 3. If driver DRV6N is connected to ADRM, the data output format of REMO is modulated or if not connected, flashed. The ADRM input has switched pull-up and pulldown loads. In the stand-by mode only the pulldown device is active. Whether ADRM is open (sub-system address 0, flashed mode) or connected to the driver outputs, this input is LOW and will not cause unwanted dissipation. When the transmitter becomes active by pressing a key, the pulldown device is switched off and the pull-up device is switched on, so that the applied driver signals are sensed for the decoding of the sub-system address and the mode of transmission. The arrangement of the sub-system address coding is such that only the driver DRVnM with the highest number (n) defines the sub-system address, e.g. if drivers DRV2N and DRV4N are connected to ADRM, only DRV4N will define the subsystem address. This option can be used in systems requiring more than one sub-system address. The transmitter may be hard-wired for subsystem address 2 by connecting DRV1N to ADRM. If now DRV3N is added to ADRM by a key or a switch, the transmitted sub-system address changes to 4. A change of the sub-system address will not start a transmission. 2/14 M3004LD REMOTE CONTROL SIGNAL OUTPUT (REMO) The REMO signal output stage is a push-pull type. In the HIGH state, a bipolar emitter-follower allows a high output current. The timing of the data output format is listed in Table 1 and 2. The information is defined by the distance tb between the leading edges of the flashed pulses or the first edge of the modulated pulses (see Figure 6). The format of the output data is given in Figure 5 and 6. The data word starts with two toggle bits T1 and T0, followed by three bits for defining the sub-system address S2, S1 and S0, and six bits F, E, D, C, Band A which are defined by the selected key. In the modulated transmission mode the first toggle bit is replaced by a constant reference time bit (REF). This can be used as a reference time for the decoding sequence. The toggle bits function is an indication for the decoder that the next instruction has to be considered as a new command. The codes for the sub-system address and the selected key are given in Table 3 and 4. The REMO output is protected against ”Lock-up”, i.e. the length of an output pulse is limited to