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CISSOID
The SOI design Specialist
CHT-CG-050
Preliminary datasheet Version 0.4 (08/2005)
Versatile High Temperature Clock Generator
General Description
The CHT-CG-050 is a versatile HighTemperature crystal clock generator with extended functional capabilities. The chip features a programmable crystal oscillator driver with an enable/disable control signal, an external clock input, a programmable divider chain and a programmable strength three-state output buffer. Using an external crystal, it is intended to provide reliable precision performance throughout the -30 to +225C temperature range for supply voltages between 3V and 5V. The CHT-CG-050 can operate with crystals from 1MHz to 50MHz. The output frequency can be selected by means of a programmable divider, providing division factors of one, two, four and eight. The programmability of the crystal driver allows working with a wide range of crystals. A crystal driver enable pin (/XtalEn) is included for extremely low power applications, as well as an output enable pin (/OE). In applications requiring only a precision divider chain, where an external clock source is already present, the crystal driver may be bypassed by means of inputs ExtClkIn and ExtClkEn.
Features
* * * * * * * * 3V to 5V power supply Qualified from -30 to +225C (Tj) Operational up to +250C (Tj) Two input sources: crystal (1 to 50 MHz), external clock (DC to 50MHz) Operation from 32.768kHz crystals Programmable frequency divider: fin, fin/2, fin/4 and fin/8 Programmable crystal driver and output driver strength Available in several standard packages or as die
Applications
* * Well logging, Automotive, Aeronautics & Aerospace Precision timing
Pin Description
C1_10pF C1_20pF C2_10pF C2_20pF DIV_0 DIV_1 Built-in capacitors with a common terminal connected to Vss.
ExtClkEn
When driven HIGH, operation from the external clock source is selected. Input for an external clock source. Output signal. When driven LOW, output is enabled, When driven HIGH, output is at high impedance. Terminal of a 200 resistor. The other terminal of this resistor is connected to X2.
ExtClkIn
Inputs to set the division factor.
TRUTH TABLE DIV_1 DIV_0 0 0 0 1 1 0 1 1 Factor 1 2 4 8
FOUT /OE
DRI_0 DRI_1
Inputs to set the output buffer strength.
TRUTH TABLE DRI_1 DRI_0 0 0 0 1 1 0 1 1 Strength 8mA 16mA 24mA 32mA
R2
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CHT-CG-050 - Preliminary datasheet - Version 0.4 (08/2005)
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Pin Description (Cnt'd)
Vdd Circuit core power supply terminal. Output buffer power supply terminal. Circuit core ground terminal. Output buffer ground terminal. Input of crystal driver
X2 XtalDR_0 XtalDR_1
Output of crystal driver Inputs to set the crystal drive strength.
TRUTH TABLE XtalDR_1 XtalDR_0 0 0 0 1 1 0 1 1 Strength Lowest Low High Highest
Vdd_Buff
Vss Vss_Buff
/XtalEn
X1
When driven LOW, the crystal oscillator is enabled. When driven HIGH, the crystal oscillator is stopped.
Internal architecture
XtalDR_0 XtalDR_1
Vdd_Buff Clock select Programmable divider 1/2/4/8
Xtal driver
R1=2M
Programmable output buffer 8/16/24/32 mA
Vss_Buff
Vdd
Vss
FOUT
R2=200
C1_10pF
C1_20pF
C2_10pF
C2_20pF
ExtClkEn
ExtClkIn
/XtalEn
R2
X1
X2
/OE
DRI_0
C1_20pF
C1_10pF
C2_20pF
C2_10pF
Figure 1. CHT-CG-050: simplified blocks diagram.
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DRI_1
DIV_0
DIV_1
CHT-CG-050 - Preliminary datasheet - Version 0.4 (08/2005)
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Absolute Maximum Ratings
Supply Voltage VDD to GND Voltage on any Pin to GND ESD Rating (expected) Human Body Model -0.5 to 6.0V -0.5 to VDD+0.3V 1kV
Operating Conditions
Supply Voltage VDD to GND Junction temperature 3.3V to 5V -30C to +225C Operation up to +250C (Tj) can be obtained with little increase of the current consumption.
Electrical Characteristics
Unless otherwise stated: VDD=5V, Tj=25C. Bold figures indicate values over the whole temperature range (-30C < Tj < +225C).
Parameter Supply voltage VDD Condition Min 3.13 VDD = 3V, FIN = 1.8MHz Output disabled (/OE: HIGH) VDD = 3V, FIN = 1.8MHz Output enabled (/OE: LOW) CL = 22pF VDD = 3V, FIN = 32MHz Output disabled (/OE: HIGH) VDD = 3V, FIN = 32MHz Output enabled (/OE: LOW) CL = 22pF VDD = 5V, FIN = 1.8MHz Output disabled (/OE: HIGH) VDD = 5V, FIN = 1.8MHz Output enabled (/OE: LOW) CL = 22pF VDD = 5V, FIN = 32MHz Output disabled (/OE: HIGH) VDD = 5V, FIN = 32MHz Output enabled (/OE: LOW) CL = 22pF VDD = 5V, FIN = 50MHz Output disabled (/OE: HIGH) VDD = 5V, FIN = 50MHz Output enabled (/OE: LOW) CL = 22pF RLOAD = 600 4.67 0.141 0.374 0.405 0.800 5.08 5.15 1.01 1.40 1.44 1.84 8.97 9.08 2.49 14.82 15.03 V mA Typ Max 5.5 Units V
Current consumptiona Idd
Minimum HIGH level output voltage VOH Maximum LOW level output voltage VOL Minimum HIGH level input voltage VIH Maximum LOW level input voltage VIL Internal capacitors Initial accuracy Temperature dependence TC1 TC2
RLOAD = 600
0.30
V
3.15
V
1.35
V
17 T = 200C C(T) = C(T0) [1+TC1.(T-T0)+ TC2.(T-T0)2] 0.6 0.023 0.013
% % 10-3/K 10-6/K2
a
The given value includes the consumption due to the load. Current consumption due to a capacitive load must be computed according to ILOAD = CL.VDD.f.
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CHT-CG-050 - Preliminary datasheet - Version 0.4 (08/2005)
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AC Electrical Characteristics
Unless otherwise stated: VDD=5V, Tj=25C. Bold figures indicate values over the whole temperature range (-30C < Tj < +225C).
Parameter Frequency range FIN Duty cycle @ 50% VDD DCb c Output rise timed 10% to 90% VDD tr Output fall timee 10% to 90% VDD tf Oscillation established after Vdd goes highf tpower-on Oscillation established after /XtalEn goes LOWg tstart-up Condition Min 1 FIN=1.8MHz, VDD = 5V FIN=32MHz, VDD = 5V FIN=50MHz, VDD = 5V Vdd = 5V, ZLOAD = 1M // 22pF Vdd = 5V, ZLOAD = 600 // 15pF Vdd = 5V, ZLOAD = 1M // 22pF Vdd = 5V, ZLOAD = 600 // 15pF VDD from 0 to 5V VDD = 5V /XtalEn from LOW to HIGH 3.0 2.5 2.5 2.1 1.2 3.2 0.6 1.4 ms ns 47/53 Typ Max 50 48/52 45/55 45/55 ns % Units MHz
ms
b c
Duty cycle is measured with a unitary division factor and ZLOAD = 1050 // 22pF. Depends on used crystal and R2 value. d Depends on load conditions and DRI_0, DRI_1 settings. e Depends on load conditions and DRI_0, DRI_1 settings. f Depends on used crystal and XtalDR_0, XtalDR_1 settings. g Depends on used crystal and XtalDR_0, XtalDR_1 settings.
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CHT-CG-050 - Preliminary datasheet - Version 0.4 (08/2005)
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Typical Performance Characteristics
16 14 12 10 8 6 4
6
1.8 MHz, /OE=LOW 10 MHz, /OE=LOW 20 MHz, /OE=LOW 32 MHz, /OE=LOW 50 MHz, /OE=LOW
5
4
Idd (mA)
Idd (mA)
3
1.8 MHz, /OE=LOW 32 MHz, /OE=LOW
2
1
2 0 25 100 150 200 225 235
0 25 100 150 200 225 235
Temperature (C)
Temperature (C)
Current consumption, VDD = 5V, /OE = LOW, CL = 22pF
Current consumption, VDD = 3V, /OE = LOW, CL = 22pF
1.00
2.60 2.40 2.20 2.00
0.80
1.8 MHz, /OE=HIGH 32 MHz, /OE=HIGH 50 MHz, /OE=HIGH
Idd (mA)
1.80 1.60 1.40 1.20 1.00 0.80 25 100 150 200 225 235
Idd (mA)
0.60
1.8 MHz, /OE=HIGH 32 MHz, /OE=HIGH
0.40
0.20
0.00 25 100 150 200 225 235
Temperature (C)
Temperature (C)
Current consumption, VDD = 5V, /OE = HIGH
55 54 53
Current consumption, VDD = 3V, /OE = HIGH
Duty Cycle (%)
1.8 MHz
52 51 50 49 48 47 25 100 150 200 225
32 MHz 50 MHz
235
Temperature (C)
Duty cycle, VDD = 5V
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CHT-CG-050 - Preliminary datasheet - Version 0.4 (08/2005)
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Circuit functionality
Operating conditions The CHT-CG-050 has been qualified for supply voltages ranging from 3V up to 5.5V. The upper limit is imposed by the technology on which the CHT-CG-050 is implemented. The qualification temperature range extends from -30C to +225C, though functionality is above +250C is achieved with little increase of the current consumption. Crystal driver XtalDR_0 and XtalDR_1 allow the crystal driver to change its strength to be able to oscillate with a wide range of crystals, under any supply (3V to 5V) and temperature (up to 225C) condition. The presence of integrated passive components offers a great versatility to the final user. Highly temperature-stable capacitors allow for a nearly-constant crystal load along the whole temperature range. Internal passive components can be bypassed or tied to ground if needed. /XtalEn enables or disables the crystal oscillator to operate, allowing the CHTCG-050 to be embedded into poweroptimized high-temperature applications. Clock source selector By means of ExtClkEn and ExtClkIn, the CHT-CG-050 is able to operate either from its internal crystal oscillator or from an external clock source. Frequency divider Four division factors (1, 2, 4 and 8) can be selected depending on the levels at the control lines DIV_0 and DIV_1. Output buffer A programmable-strength output buffer, controlled by DRI_0 and DRI_1, enables the CHT-CG-050 to drive a large range of output loads, improving the output signal integrity. The four possible output strengths are 8mA, 16mA, 24mA and 32mA. The output buffer has supply terminals independent from the rest of the circuit, allowing the system designer to properly decouple them in noise-sensitive application.
Figure 2. Effect of DRI_0 and DRI_1 on the output signal. Figure 2 shows the superposition of the output signal when DRI_0, DRI_1 = LOW and DRI_1 is then set to HIGH, VDD=3V, T=235C, Freq = 27MHz. As a result, the signal integrity is improved.
Packaging options As mentioned above, the layout of the CHT-CG-050 allows for a very high level of flexibility for the system designer. Several packaging configurations are possible, from 8-pin to 24-pin standard carriers. At the packaging stage, many functional features can be enabled or safely disabled in order to optimize the form factor according to the final user needs. Typical application The CHT-CG-050 offers the final user several possible configurations depending upon the characteristics of the target application.
Figure 3. Full configuration.
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CHT-CG-050 - Preliminary datasheet - Version 0.4 (08/2005)
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Dashed lines in Figure 3 indicate optional connections. Figure 4 shows the minimal possible configuration with no external components. Any configuration in between those of Figure 3 and Figure 4 can be obtained by properly bypassing or tying to ground the corresponding internal component. Any programmable feature can be changed on-the-fly, allowing the CHT-CG050 to accommodate to new operating conditions in smart or adaptive applications.
Figure 4. Minimal configuration.
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CHT-CG-050 - Preliminary datasheet - Version 0.4 (08/2005)
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Possible Packaging Options
Figure 5. CHT-CG-050: possible packaging options.
NOTES:
The CHT-CG-050 can also be ordered as die. Packaging options shown are only indicative. Other possibilities are also available. Ask CISSOID for other packaging configurations.
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CHT-CG-050 - Preliminary datasheet - Version 0.4 (08/2005)
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Contact & Ordering
CISSOID S.A. Chemin du Cyclotron 6 1348 Louvain-la-Neuve Belgium Tel : +32-10-489210 Fax : +32-10-489219 sales@cissoid.com http://www.cissoid.com
Disclaimer
Neither CISSOID, nor any of its directors, employees or affiliates make any representations or extend any warranties of any kind, either express or implied, including but not limited to warranties of merchantability, fitness for a particular purpose, and the absence of latent or other defects, whether or not discoverable. In no event shall CISSOID, its directors, employees and affiliates be liable for direct, indirect, special, incidental or consequential damages of any kind arising out of the use of its circuits and their documentation, even if they have been advised of the possibility of such a damage. The circuits are provided "as is". CISSOID has no obligation to provide maintenance, support, updates, or modifications.
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