STLED316SMTR ,Serial-interfaced 6-digit LED controller with keyscanelectrical characteristics . . . 115.2 Power consumption estimation . 125.3 Capacitance ..
STLM20DD9F ,Ultra-low current 2.4 V precision analog temperature sensorapplications where maximizing battery life is important. It operates over a –55 °C to 130 °C (grade ..
STLM20W87F ,Ultra-low current 2.4 V precision analog temperature sensorApplications■ Smartphones■ Multimedia PDA devices■ GPS devices■ Portable medical instrumentsUDFN-4L ..
STLM75DS2F ,Digital temperature sensor and thermal watchdogFunctional description . . . . . . 163.1 Registers and register set formats . . . . . . 163 ..
STLM75M2E , Digital temperature sensor and thermal watchdog
STLM75M2F ,Digital temperature sensor and thermal watchdogFeatures ■ Measures temperatures from –55°C to +125°C (–67°F to +257°F)– ±0.5°C (typ) accuracy– ±2° ..
SY10EL31ZC , D FLIP-FLOP WITH SET AND RESET
SY10EL31ZC , D FLIP-FLOP WITH SET AND RESET
SY10EL31ZC , D FLIP-FLOP WITH SET AND RESET
SY10EL31ZG , D FLIP-FLOP WITH SET AND RESET
SY10EL31ZG , D FLIP-FLOP WITH SET AND RESET
SY10EL32V , 5V/3.3V ÷ 2 DIVIDER
STLED316SMTR
Serial-interfaced 6-digit LED controller with keyscan
January 2008 Rev 1 1/33
STLED316SSerial-interfaced 6-digit LED controller with keyscan
Features LED driver with 14 outputs
(8 segments/6 digits) 40 mA load current capability for each segment Output pins connected directly to the LEDs or
can be open-drain Key-scanning (8x 2 matrix) Low power consumption in standby mode 3-wire serial bus interface (CLK, STB,
DIN/DOUT) 8-step dimming circuit to control the overall
display brightness Single external resistor for output current
setting Inputs with Schmitt trigger give superior noise
immunity A single LED digit output (DIG1_LED) can be
used to drive up to 8 discrete LEDs 8-step dimming circuit to control brightness of
individual LEDs for LED digit 5.0 V (± 10%) for VCC Drives common-anode LED digits Built-in power on reset and soft-start circuits Available in SO24 package -40 °C to 85 °C operating temperature range
Applications Set-top-boxes White goods Home appliances DVD players and VCRs
Table 1. Device summary
Contents STLED316S2/33
Contents STLED316S functional and application diagram . . . . . . . . . . . . . . . . . . 3 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 STLED316S functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73.1 Low power mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2 Serial interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.3 Initial power up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.4 Display types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.5 Keyscan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.6 Discrete LED outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.7 Power on reset and soft-start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.8 LED drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.9 Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.10 Operating the device with 3.3 V interface voltages . . . . . . . . . . . . . . . . . . 9
Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.1 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Recommended operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . 115.1 DC electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.2 Power consumption estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.3 Capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.4 Power supply characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.5 Dynamic switching characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.6 Timing characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.7 ESD performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Key-scan & display cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Key matrix and key-input data storage ram . . . . . . . . . . . . . . . . . . . . . 15 Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
STLED316S Contents
3/33
8.1 Write command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
8.2 Read command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.3 Device configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
8.3.1 Display setting (maximum number of digits): . . . . . . . . . . . . . . . . . . . . . 19
8.3.2 Dimming setting (brightness levels): . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
8.4 Display memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Key-scanning and display timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
9.1 Serial communication format (reception) . . . . . . . . . . . . . . . . . . . . . . . . . 23
9.2 Serial communication format (transmission) . . . . . . . . . . . . . . . . . . . . . . 24 Switching characteristics waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
11.1 Graph of ISET against RSET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
11.2 Power supply sequencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
11.3 Application diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
List of figures STLED316S
4/33
List of figures
Figure 1. STLED316S functional diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 2. STLED316S application diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 3. STLED316S pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 4. Key matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 5. Serial communication format (reception) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Figure 6. Serial communication format (transmission). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 7. Switching characteristics waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 8. Graph of ISET against RSET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 9. STLED316S application diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 10. SO-24 package outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
STLED316S List of tables
5/33
List of tables
Table 1. Device summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Table 2. Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 3. Seven segment display with dot point and common-anode LED panel . . . . . . . . . . . . . . . 11
Table 4. Absolute maximum ratings (all voltages are referenced to GND). . . . . . . . . . . . . . . . . . . . 13
Table 5. Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Table 6. DC electrical characteristics
(TA= -40 to +85 °C, VCC=5.0 V ± 10%, GND=0V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 7. Capacitance (TA=25 °C, f=1 MHz) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 8. Power supply characteristics (TA = -40 to +85 °C). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 9. Dynamic switching characteristics
(TA= -40 to +85 °C, VCC=5.0 V ± 10%, GND=0.0 V, typical values are at 25 °C) . . . . 16
Table 10. Timing characteristics
(TA = -40 to +85 °C, VCC=5.0 V ± 10%, GND = 0.0 V, Typical values are at 25 °C) . . . . 16
Table 11. ESD performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 12. Read command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Table 13. Memory page mapping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Table 14. Digit address mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Table 15. LED address mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Table 16. Memory page address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 17. 7-segment display address. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 18. LED display address. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 19. Part list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Table 20. SO-24 package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 21. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
STLED316S functional and application diagram STLED316S
6/33 STLED316S functional and application diagram
The STLED 316S consists of the following blocks: Current source POR and soft-start Interrupt generator Serial interface Digital logic blocks Drivers
Figure 1. STLED316S functional diagram
STLED316S STLED316S functional and application diagram
7/33
Figure 2. STLED316S application diagram
Pin description STLED316S
8/33
2 Pin description
Figure 3. STLED316S pin connection
Table 2. Pin description
STLED316S Pin description
9/33
Table 2. Pin description (continued)
STLED316S functional description STLED316S
10/33 STLED316S functional description
The STLED316S is a common-anode LED driver controller which can be used to drive red,
green or blue LEDs as the current is adjustable through the external resistor. In the common
anode configuration, the segment outputs sink the current from the cathodes while the digit
outputs source the current to the anodes. The configurable output current can be used to
drive LEDs with different current ratings (red, green or blue). The brightness of the whole
display can be controlled through the serial interface as described later. The outputs can be
connected together in parallel to drive a single LED. In this case, two parallel current
sources of equal value drive a single LED. The external resistor value can be set accordingly
to determine the desired output current thus controlling the display brightness.
Soft-start limits the inrush current during power-up. The display is blanked (LEDs are turned
off or in high-Z state) on power-up.
3.1 Low power mode of operation
Upon initial power up or when not configured or when not used, the STLED316S will be in
low power mode of operation wherein the current consumption drops to less than 1mA.
During this mode, the data configured is maintained as long as the supply voltage is still
present (the contents of the internal RAM need the supply voltage to be present). Port
configuration and output levels are restored when the STLED316S resumes normal
operation. For minimum supply current in shutdown mode, logic inputs should be at GND or
VCC.
3.2 Serial interface
The interface is used to write configuration and display data to the STLED316S. The serial
interface comprises of a shift register into which DIN is clocked on the rising edge of the
CLK when STB is low. When STB is low, falling transitions on CLK clock the data from the
device to the microcontroller. The 8-bit data is decoded to determine and execute the
command.
STB indicates to the device the start of communication when it goes low. DIN/DOUT pin is
bi-directional. The data will be validated during positive pulse of the clock in both write/read
modes. If the STB signal goes high before completing the data byte write to the device, the
preceding data bits are ignored and the previous configuration remains intact.
3.3 Initial power up
On initial power-up, all control registers are reset, the display is blanked and the
STLED316S is in the low power mode. All the outputs are in high-impedance state at initial
power-up. The DIN/DOUT is pulled high by an external pull-up resistor. The display driver
has to be configured before the display can be used.
STLED316S STLED316S functional description
11/33
3.4 Display types
Table 3. Seven segment display with dot point and common-anode LED panel
3.5 Keyscan
The full keyscan is illustrated in the another section of the datasheet. One diode is required
per key switch. The keyscan circuit detects any combination of keys being pressed.
3.6 Discrete LED outputs
The STLED316S can be used to drive up to 8 discrete LEDs. The single LED output acts
like a digit driver output and can be wired-up with 8 segment outputs to drive up to 8 different
discrete LEDs. Physical connections from the LED output as well as the segment outputs
must be made to drive the discrete LEDs in the desired manner. The discrete LEDs may be
needed to indicate the “Power”, “Standby” status (for example). Also it is possible to
separately control the brightness of each single LED.
3.7 Power on reset and soft-start
The device integrates an internal power-on-reset circuit which initializes the digital logic
upon power up. The soft-start circuit limits the inrush current and high peak current during
power-up. This is done by delaying the input circuit’s response to the external applied
voltage. During soft-start, the input resistance is higher which lowers the in-rush current
when the supply voltage is applied.
STLED316S functional description STLED316S
12/33
3.8 LED drivers
The constant current capability is up to 40 mA per output segment and is set for all the
outputs using a single external resistor. When acting as digit drivers, the outputs source
current to the display anodes. When acting as segment drivers, the LED outputs sink current
from the display cathodes. The outputs are high impedance when not being used as digit or
segment drivers.
Each port configured as a LED digit driver behaves as a digitally-controlled constant current
sink. The LED drivers are suitable for both discrete LEDs and common anode (CA) numeric
LED digits. When fully configured as a LED driver, the STLED316S controls up to 8 LED
segments in a single digit with 8-step logarithmic brightness control for the digits. A single
resistor sets the maximum segment current for all the segments, with a maximum of 40mA
per segment. The STLED316S drives any combination of discrete LEDs and CA digits for
numeric displays.
The recommended value of RSET is the minimum allowed value, since it sets the display
driver to the maximum allowed segment current. RSET can be a higher value to set the
segment current to a lower maximum value where desired. The user must also ensure that
the maximum current specifications of the LEDs connected to the drivers are not exceeded.
The brightness of the individual digits in the display panel can be controlled separately.
3.9 Interrupt
The device includes an active low level IRQ_N pin to the microprocessor. The STLED316S
generates an interrupt when a key is pressed.
3.10 Operating the device with 3.3 V interface voltages
The device can detect the input voltage levels reference to 3.3 V from the main controller
chip as long as the VIL and VIH specifications of the STLED316S are met. If the input
voltage to STLED316S is greater than 2.9 V, the STLED316S will recognize the signal level
as a valid high and if the input voltage is lower than 1.75 V, it will be recognized as a valid
low level.
For the output signals from the device like DOUT and IRQ_N, the signal level depends on
the external supply to which the external pull up resistor is connected to. Thus this
eliminates the use of any level shifter between the main controller and the STLED316S.
STLED316S Maximum rating
13/33
4 Maximum rating
Stressing the device above the rating listed in the “Absolute maximum ratings” table may
cause permanent damage to the device. These are stress ratings only and operation of the
device at these or any other conditions above those indicated in the operating sections of
this specification is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability. Refer also to the STMicroelectronics SURE
program and other relevant quality documents.
4.1 Thermal data
Table 4. Absolute maximum ratings (all voltages are referenced to GND) De-rate at -9.6 mW/°C at TA = 25°C or higher In accordance with the JEDEC standard
Table 5. Thermal data
Recommended operating conditions STLED316S
14/33 Recommended operating conditions
5.1 DC electrical characteristics
Table 6. DC electrical characteristics
(TA= -40 to +85 °C, VCC=5.0 V ± 10%, GND=0V)
STLED316S Recommended operating conditions
15/33
5.2 Power consumption estimation
Each port of the STLED316S can sink a maximum current of 40 mA into an LED with a
4.4 V forward voltage drop when operated from a supply voltage of 5.0 V. The minimum
voltage drop across the internal LED drivers is thus 5.0-4.4=0.6V . The STLED316S can
sink 8x40= 320 mA when all outputs are operating as LED segment drivers at full current.
On a 5.0 V supply, a STLED316S dissipates (5.0V-4.4V)x 320mA= 192 mW when
driving 8 of these 4.4 V forward voltage drop LEDs at full current. If the application requires
high drive current, consider adding a series resistor to each LED to drop excessive drive
voltage off-chip.
If the forward voltage of the LED is lesser than 4.4 V (say 2.4 V), then the maximum power
dissipation of STLED316S when all segments are turned on will be (5- 2.4) V x
320mA= 832 mW. To lower the power dissipation, consider adding a small series resistor
in the supply. Another alternative is to increase the value of the RSET to lower the current of
the LEDs from 40 mA to say 30 or 20 mA.
The efficiency will be the power consumption in the LEDs divided by the input power
consumed.
Efficiency= Vdiode x Idiode / VCC x ICC
As an example, consider LED with forward voltage of VF = 2.4V, Ipeak = 40 mA,
VCC (max) = 5.5 V, N= number of segments=8 (max), D= duty cycle= 15/16,
Power dissipation, PD (max)=5mAx5.5 V + (5.5- 2.4) V x (15/16) x 40 mA x 8 = 27.5 + 780
= 807.5 mW. To lower this value, add a series resistor with the supply.
5.3 Capacitance
5.4 Power supply characteristics
Table 7. Capacitance (TA =25°C, f=1MHz)
Table 8. Power supply characteristics (TA = -40 to +85 °C)
Recommended operating conditions STLED316S
16/33
5.5 Dynamic switching characteristics
5.6 Timing characteristics
5.7 ESD performance
Table 9. Dynamic switching characteristics
(TA= -40 to +85 °C, VCC=5.0 V ± 10%, GND=0.0 V, typical values are at °C)
Table 10. Timing characteristics
(TA = -40 to +85 °C, VCC=5.0 V ± 10%, GND = 0.0V , Typical values are at °C)
Table 11. ESD performance
STLED316S Key-scan & display cycle
17/33 Key-scan & display cycle
The display RAM stores the data transmitted from an external device to the STLED316S
through the serial interface. Refer to Section 9: Key-scanning and display timing on page25
for a pictorial representation.
The grid and segment outputs are controlled by the display output module. The entire grid
will be turned off on channel 1/16 and 16/16 meaning that the first channel and last channel
are off. This is referred to as blanking time.
During the keyscan time (first cycle from timing generator), the entire grid is turned off and
only the segments are enabled one by one (seg0 to seg7). The segment on time is 64 µs.
During the LED discrete time (second cycle), the data present on the internal LED buffer is
checked. If the data is present, then the brightness setting of each LED in the brightness
control register is checked. Then each segment will be enabled or disabled based on the
register value. In this duration, the grids 1 to 6 are turned off. The grid corresponding to LED
digit is turned on. The LED on duty cycle is 14/16. If the LED/seg1 brightness is 12/16, it
means that the segment1 OFF time is 12/16 and on time is 2/16.
During 7-segment display time (3rd cycle to 8th cycle), the display status is checked whether
it is ON or OFF . If display is ON, then the dimming settings are checked from the
configuration register for the grid (it may be common dimming setting or individual dimming
setting for each digit). The minimum turn on time is 1/16 and maximum turn on time is 14/16.
The blanking time is valid before the turning on and turning off of the grid. The blanking
interval is 32 µs. This will continue until the maximum number of digits configured in the
register. Once the full cycle is complete, the keyscan cycle will start again.
If the display is not turned on, then the timing generation will immediately go to the key scan
mode.
Initial:
All the segments and grids are turned off.
During operation:
1. Turn on segment (keyscan) one by one. On time duration is 64 µs.
2. Check the data present in LED register. If data is present, turn on the respective LED
grid and segments.
3. Check the display on. If display is turned on, then enable the grid one by one from grid
1 to grid 6 (maximum) and turn on segments.
