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OKI Semiconductor ML9298
12-Hour System Clock IC for 1/2 Duty Fluorescent Display Tubes
FEDL9298-01 Issue Date: Jul. 11, 2005
GENERAL DESCRIPTION
The ML9298 is a 12-hour system clock IC that drives 1/2 duty fluorescent display tubes. It has a wide range of power supply using an oscillation source of 4.194304 MHz. The ML9298 has a time adjustment function in hour, minute and 30-minute units, and the function has two adjustment modes, 1 Push 1 ADJ and 2Hz fast forward. Additionally, it has a brightness adjustment function for the fluorescent display tube, providing four levels of brightness settings.
FEATURES
• • • • • • 12-hour system Wide power supply range from 4 to 18V (built-in voltage regulator circuit) Designed for 1/2 duty fluorescent display tubes 4.194304MHz (crystal oscillation) Four levels of brightness settings Package: 32-pin plastic SSOP (SSOP32-P-430-1.00-K) (ML9298MB)
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FEDL9298-01
OKI Semiconductor
ML9298
BLOCK DIAGRAM
Logic circuits VDDIN Power-on reset circuit RESET XT Grid driver XT DIM1 DIM2 Frequency divide circuit Grid decoder GR1 GR2 F64HZ
2a, 2d Time adjustment Second counter 4b, 4c, 2b Minute counter Segment decoder Segment driver Hour counter 2f 2c, col 2e 2g 3d, 1d 3e, 1e 3c, 1c 3g, 1g RESET COLSEL 3f, 1f 3b, 1b 3a, 1a TEST VDDOUT 3V regulator VCC High voltage circuit MS HS ZA
BLANK
A/C
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ML9298
PIN CONFIGURATION (TOP VIEW)
VCC VDDOUT VDDIN TEST DIM1 DIM2 BLANK HS MS ZA A/C XT XT (NC) F64HZ GND
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
32 GR2 31 GR1 30 2a, 2d 29 4b, 4c, 2b 28 2f 27 2c, col 26 2e 25 2g 24 3d, 1d 23 3e, 1e 22 3c, 1c 21 3g, 1g 20 3f, 1f 19 3b, 1b 18 3a, 1a 17 COLSEL
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ML9298
PIN DESCRIPTION
Pin DIM1 DIM2 A/C ZA HS MS BLANK COLSEL XT XT TEST F64Hz GR1 GR2 1a, 3a to 2b, 4b, 4c VCC GND VDDOUT VDDIN NC I/O I I I I I I I I I O I O O O O I Pull-up/ Pull-down Pull-down Pull-down Pull-up Pull-up Pull-up Pull-up Pull-down Pull-up Description Brightness switching pin. Input pin with a pull-up resistor to reset the circuits inside this LSI at a “L” level. Set the reset pulse width to 2 ms or more. Zero adjust pin. Hour digit adjustment pin. Minute digit adjustment pin. Blank input pin. Display disappears at a “L” level. This is the input pin for selecting flashing or lighting of the colon output. "L" level : Flashing, "H" level : Lighting Crystal oscillation pin to connect a crystal and capacitors Cx and Cy externally. IC testing pin. Leave this pin open or fix it to a “H” level. 64Hz signal output pin for oscillation frequency adjustment. Output pins for the 1/2 duty fluorescent display tube grids. Output pins for the 1/2 duty fluorescent display tube anodes. Power supply pin for high voltage. Ground pin. built-in regulator output pin for logic circuits. Connect the pin to the VDDIN pin. Power supply pin for logic circuits. Connect the pin to the VDDOUT pin. NC pin. Leave the pin open.
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ML9298
ABSOLUTE MAXIMUM RATINGS
Parameter Power supply voltage (High voltage) Power supply voltage (Logic) Input voltage (High voltage) Input voltage (Logic) Output voltage (High voltage) Output voltage (Logic) Output current (High voltage) Output current (Logic) Power dissipation Storage temperature Symbol VCC VDDIN VHI VLI VHO VLO IHO ILO PD TSTG Condition Ta = 25°C Ta = 25°C Ta = 25°C Ta = 25°C Ta = 25°C Ta = 25°C Ta = 25°C Ta = 25°C Ta ≤ 85°C — Rating –0.3 to 20 –0.3 to 6.5 –0.3 to VCC +0.3 –0.3 to VDDIN+0.3 –0.3 to VCC +0.3 –0.3 to VDDIN+0.3 –30 to 3 –5 to 5 350 –55 to 150 Unit V V V V V V mA mA mW °C
RECOMMENDED OPERATING CONDITIONS
Parameter Power supply voltage (High voltage) Power supply voltage (Logic) Operating temperature Crystal frequency Symbol VCC VDDIN Ta f(X'tal) Condition — — — — Min. 4.0 2.8 –40 Typ. 12.0 3.2 25 4.194304 Max. 18.0 3.6 85 Unit V V °C MHz
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ML9298
ELECTRICAL CHARACTERISTICS
DC Characteristics
(Vcc = 4.0 to 18.0 V, VDDIN = 2.8 to 3.6 V, Ta = −40 to 85°C) Condition Min. Typ. Max. Unit VCC = 4 to 18 V VCC = 4 to 18 V VCC = 12 V VIN = VCC VCC = 12 V VIN = 0 V VCC = 12 V VIN = VCC VCC = 12 V VIN = 0 V VCC = 12 V VIN = VCC VCC = 12 V VIN = 0 V VCC = 12 V IOH1 = −1 mA VCC = 12 V IOL1 = 0.55 mA VCC = 12 V IOH2 = −2 mA VCC = 12 V IOL2= 0.55 mA VCC = 12 V IOH3 = −15 mA VCC = 12 V IOL3 = 0.55 mA VDDIN = 3.0V IOH4 = −0.1mA VDDIN = 3.0V IOL4 = 0.1mA *4) VCC×0.8 — 20 −2 −2 –200 –2 –2 VCC–2.0 — VCC–2.0 — VCC–2.0 — VDDIN–0.5 — — — — 65 — — –65 — — — — — — — — — — 400 — VCC×0.2 200 2 2 –20 2 2 — 2 — 2 — 2 — 0.5 600 V V µA µA µA µA µA µA V V V V V V V V µA
Parameter "H" input voltage "L" input voltage *1) *1)
Applicable pin
Symbol VIH VIL IIH1 IIL1 IIH2 IIL2 IIH3
DIM1, DIM2, BLANK, COLSEL ZA, HS , MS , A/C, TEST
Input current
COLSEL IIL3 VOH1 *2) VOL1 VOH2 *3) VOL2 Output voltage VOH3 GRID1, GRID2 VOL3 VOH4 F64HZ VOL4 Dynamic supply current
*
VCC
ICC
1) Applicable to the following pins: DIM1, DIM2, BLANK, TEST, ZA, HS, MA, A/C, and COLSEL * 2) Applicable to the following SEGMENT output pins: 1a and 3a, 1b and 3b, 1c and 3c, 1d and 3d, 1e and 3e, 1f and 3f, 1g and 3g, 2g, 2e, and 2f * 3) Applicable to the following SEGMENT output pins: 2a, 2d, 2b and 4b, 4c and 2c, and col *4) f = 4.194304 MHz, Cg = Cd = 33pF, VCC = 12V, open input, and non-loaded output
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ML9298
FUNCTIONAL DESCRIPTION
Time Base Built-in 4.194304MHz crystal oscillation circuit (AMP, feedback resistor) * Keep crystal and external capacitors as close to this LSI as possible to minimize connection wiring. * The values of external components, such as crystal and capacitors, should be determined including capacitance of user's circuit boards. It is recommended to contact a crystal manufacturer. 7-Segment Display Format
A F G E D C B
(7 segments)
Display Device Dynamic drive 4-digit fluorescent display tube (with colon) Relationship Between Anode/Grid Output and Display
GR2 4b 3f 3a col 3g 3b 2f 2g 2b 1f 1b 1g 1c 1d digit1 GR1 2a 1a
4c
3e 3d digit3
3c col
2e 2d digit2
2c 1e
digit4
colon
Brightness Switching Function 4-level brightness settings (frequency = 256 Hz, gap between GR1 and GR2 at 1/2 duty = 32 µs)
Switch pin name DIM1 L H L H DIM2 L L H H Operating mode f = 256 Hz, 1/2 duty (50% display) f = 256 Hz, 1/4 duty (25% display) f = 256 Hz, 1/8 duty (12.5% display) f = 256 Hz, 1/16 duty (6.25% display)
Display Mode 4-digit hour and minute display in 12-hour system Hour display ·················· 1 to 12 Minute display ············ 00 to 59 No time display when the most significant digit is 0 (Most Significant Digit Zero Suppress function)
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ML9298
Time Adjustment Hour/Minute Fast-forwarding Function Hour and minute can be fast-forwarded separately. The HS (Hours Set) pin fast-forwards the hour digits, and the MS (Minutes Set) pin fast-forwards the minute digits individually at 2Hz. One push counts one hour or one minute. When continuously pushed, hour or minute is incremented at 2Hz. The HS and MS pins are held at a “H” level by a pull-up resistor in the open state, being in the no active state. These pins are placed in the active state by driving them at a “L” level externally. The fast-forwarding of the hour and minute digits can be performed simultaneously. When fast-forwarding the hour digits, the lower counter continues a regular operation, but the carry-over from the minute to the hour is not performed. When fast-forwarding the minute digits, carry over to the hour digits is not performed. Zero Adjustment Function (±30 minute reset to zero) The ZA (Zero Adjust) pin is held at a “H” level by a pull-up resistor in the open state, being in the no active state. This pin is placed in the active state by driving it at a “L” level externally so that hours, minutes and seconds can be adjusted to zeros. If the minute digits is less than 30 minutes, the minute and second digits are reset to 00’00”. Also, if the minute digits exceed 30 minutes, the minute and second digits are reset to 00’00”, and the hour digits are carried over. Moreover, the counter below seconds is reset up to 8 Hz. (X−1) hours 30 minutes 00 seconds X hours 00 minutes 00 seconds (X) hours 29 minutes 59 seconds (X) hours 30 minutes 00 seconds X hours 59 minutes 59 seconds (X+1) hours 29 minutes 59 seconds
→ X hours 00 minutes 00 seconds → (X+1) hours 00 minutes 00 seconds
Blanking of Display Blanking occurs in display by driving the BLANK pin at a “L” level externally. Inputs from HS, MS, and ZA pins are disabled during blanking. F64Hz Pin This is the output pin for oscillation frequency adjustment, and constantly outputs a 64Hz signal. External Reset This device can be reset by placing the A/C pin at a “H” level. After reset, the display starts at “1: 00”. Built-in Regulator Circuit The built-in regulator circuit reduces the power supply voltage (VCC) for the high voltage to the power supply voltage for logic , which is output to the VDDOUT pin. Power is supplied to logic circuitry by connecting the VDDOUT pin to the VDDIN pin. Power-on Reset The power-on reset circuit built in this device eliminates the need for providing an external reset circuit. * Do the followings to operate the power-on reset circuit properly: - Make a slope of a rise time of VCC to a voltage equal to or larger than 8V/ms. - Connect a smoothing capacitor of 1000 pF±20% or more between the VDDOUT pin and GND.
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ML9298
TEST pin This is the pin for testing this device. This pin should be left open or fixed at a “H” level when not used. Removal of C
