View AMIS-70020_1209570.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

AMIS-70020 Power Failure Elapsed Time Counter
1.0 General Description
The AMIS-70020 is a timer IC that measures the duration of power failures of up to five hours. The AMIS-70020 starts and stops counting automatically as it is triggered by the voltage of the input signal VCC. When VCC gets lower than the reference signal VDD - VTH, a power cut-off is flagged and the AMIS-70020 starts counting. During the counting phase the AMIS-70020 is powered by an external capacitor or by a primary battery and consequently operates independently of an external power supply. Due to the low power design of the AMIS-70020, the device can count the full scale autonomously using the energy stored in a 10mF capacitor. As soon as VCC comes up again counting stops. The value of the counter is shifted to the digital Q_OUT output pin and is communicated to a microprocessor. After shifting the full counted value, the internal RC-oscillator signal is put on the Q_OUT output pin. Using this data the microcontroller can calculate the duration of the power failure. The internal power management circuit manages the recharge of the external buffer capacitor.
Data Sheet
The few external components required to build the AMIS70020 into its application result in a cost effective solution and in a footprint of less than 2cm2. The combination of an internal oscillator and a microcontroller software algorithm eliminate the requirement for a space and cost consuming external crystal. Typical applications are those sensitive to power failures that do not have a built-in UPS function. Examples are: * Power inverters/Motordrivers/Soft starters * Accurate I2t protection possible even after power loss * Thermal protection devices for electrical motors without integrated thermistor * Motor controllers for electrical motors without integrated thermistor * Process control * Chemical processes * Industrial mixers * Mixing reactors
2.0 Key Features
* Measures the time elapsed during a power failure * Measures up to five hours * 1 second resolution (RC oscillator/1024) * Autonomous operation during power failure * Auto switching to backup power * Auto counter-start/stop function * Maintenance free buffer capacitor - 6 hours back-up with 10mF - Capacitor recharge management built in (no external diode needed) * Li-button cell - CR1220 (35mAh) supports up to 10 years in a typical application * Low current consumption <1A * Built-in 1kHz oscillator * No external oscillator required * Frequency of oscillator can be read by an external microcontroller * Accurate time measurement possible using software calibration algorithm * 2-wire interface with standard I/O pins of a microcontroller * Operating temperature -10~85C * 150 mils SO8 package * Few external components * Easy design-in due to a user friendly application board
3.0 Ordering Information
Ordering Code Package Temp. Range Ordering Code AMIS-70020 SO8 -10C...-85C EVK-70020 Evaluation kit
For sample requests contact your local sales representative at www.amis.com/sales.
AMI Semiconductor www.amis.com
1
AMIS-70020 Power Failure Elapsed Time Counter
4.0 Block Diagram
Data Sheet
VCC
CUT_OFF Test
1
CUT_OFF Switch
3
Test_Detect
8
CUT_OFF COMPARATOR VDD
0 m3 1
2
C
POR
OUT_PORB CUT_OFF_CMD CONTROL
Oscillator CLK_1K 1 kHz
0 m1 1
Divider (10 bits)
0 m2 1
Register/Counter (15 bits)
0 m0 Q14_OUT 1 EN0
Q_OUT
5
UC_CLK_IN
Uc_Clk
6
CLK_1S
Current_source
7
Clk
4
VSS
5.0 Packaging
The AMIS-70020 is packaged in a 150mils SO8. Please visit http://www.amis.com/pdf/soic.pdf for detailed mechanical information. Pinout
VCC
VDD Test_Out CUT_OFF VSS 4 3
1
8 Test 7
AMIS70020
2
Clk 6 Uc_Clk 5 Q_Out
Pad Description Pad No. 1 2 3 4 5 6 7 8 Name VCC VDD CUT_OFF VSS Q_OUT Uc_Clk Clk Test Type Power Power Digital Output Power Digital Output Digital Input Digital Output Digital Input Comment System power that is monitored Back-up power Not connected, test purpose only Ground Shift register output (CMOS output buffer 2mA) CLK from microcontroller (Schmitt trigger input); an internal pull down (100K) is connected on the pin Internal oscillator/1024 (1Hz) (CMOS output buffer 2mA) For normal operation: connect to GND
AMI Semiconductor www.amis.com
2
AMIS-70020 Power Failure Elapsed Time Counter
6.0 Application Diagram
Data Sheet
Supply 5V
100nF
MICRO
VCC 10 mF VDD CUT_OFF VSS 4 3
The power supplies of the chip need to be properly decoupled. This means that at least one external capacitor CDD must be connected in between VSS and VCC. Typical External Components Component Capacitor Capacitor 1 Li Battery 1, 2 Function Filter Backup power supply Backup power supply Typical Value Tol 100 +- 20% 10 +- 10% CR1220 (35mAh) Unit nF mF 1) Either a buffer capacitor of a Li-battery is selected as a backup power supply. 2) In case a Li-battery is used as a backup power supply a diode is must be placed between the AMIS-70020 and the battery to disable the charging feature.
7.0 Electrical and Environmental Ratings
Operating Ranges This section defines the limits for functional operation and parametric characteristics of the device as described elsewhere in this document. Note that functionality of the IC outside the operating ranges is not guaranteed. Symbol VCC VDD Tamb Tj Cla VIH VIL VOH VOL Description Power supply voltage Power supply voltage Ambient temperature under bias Junction temperature Load capacitance on outputs Digital input levels Digital output levels Min 4.5 2 -10 Operation outside the operating ranges for extended periods may affect device reliability. Total cumulative dwell time above the maximum operating rating for power supply or temperature must be less than 100 hours. Max 5.5 5.5 85 135 70 Unit V V C C pF V 30%VDD V V 0.4 V
1
8 Test 7 7
AMIS70020
2
Clk
< >
6 5
Uc_Clk Q_Out
70% VDD 2.5
Input operating range of digital IO's 0-VDD Output operating range of digital IO's 0-VDD
AMI Semiconductor www.amis.com
3
AMIS-70020 Power Failure Elapsed Time Counter
Absolute Maximum Ratings Stresses above those listed in this clause may cause immediate and permanent device failure. It is not implied that more than one of these conditions can be applied simultaneously.
Data Sheet
Symbol VCC VDDmr Tamb,mr Tj,mr VIH VIL
Description Power supply voltage Power supply voltage Ambient temperature under bias Junction temperature Digital input levels
Min -0.3 -0.3 -10 VDD + 0.3
Max 7 7 85 150 VDD - 0.3
Unit V V C C V V
Electrical Overstress Immunity Electrostatic discharges on component level: (1) The device withstands 2000V Human Body Model ESD pulses when tested according to MIL STD 883 method 3015.5 (pin combination 2). Latch-up immunity: (2) Static latch-up protection level is 100mA at 25C when tested according to EIA/JESD78.
8.0 Detailed Electrical and Functional Description
Digital Interface The digital interface with a microcontroller can be made by means of only two digital connections. The first is the clock signal to be applied to the AMIS-70020 UC_CLK pin and the second is the data line to be read by the microcontroller from the Q_OUT pin. After a POR or after a power failure (CUT_OFF) the 15 bit shift register is loaded with the counter value and connected to the Q_OUT pin. The most significant bit, MSB is already present and can be read at the Q_OUT pin. Applying clocks at a maximum rate of 10MHz on UC_CLK will shift out the remaining counter bits. After the fifteenth clock, the internal oscillator frequency will be connected to the Q_OUT pin as a running clock signal. By measuring the period of this signal, the time a cut-off was present can be calculated by the microcontroller. An internal pull down resistor is connected to the pin Q_OUT, in order to avoid the parasitic shift of the counting register. If VCC is powered up, a third optional pin - CLK - gives the counter clock signal of about 1Hz. This clock is the internal oscillator, divided by 1024 and can also be used to calibrate the application. Connections made with the microcontroller are separated by level shifters. When in power failure mode, the inputs of the AMIS-70020 are fixed to zero state. This will prevent unwanted current leaking.
AMI Semiconductor www.amis.com
4
AMIS-70020 Power Failure Elapsed Time Counter
Timing Diagram
Data Sheet
Flowchart The flowchart depicts the operation of the AMIS-70020 in case VCC gets smaller than VDD-VTH. After this flow has been finished the buffer capacitor is recharged and the timer IC is ready for a new cycle.
AMI Semiconductor www.amis.com
5
AMIS-70020 Power Failure Elapsed Time Counter
Description of the Main Building Blocks Oscillator The AMIS-70020 integrates an oscillator that functions without any external components. The maximum accuracy of the time measurement can only be obtained if the measured time is calibrated with the actual oscillator Symbol Fosc Comparator When VCC < VDD - VTH, the comparator output (CUT_OFF) is commuted. CUT_OFF signal is used by the digital control to put the circuit in cut_off mode. Description Absolute frequency at ambient Min 0.5 Typ 0.9
Data Sheet
frequency. This can be done since the oscillator output frequency can be measured by the microcontroller on the Q_out pin after the measured counter value has been shifted out the register. Max 1.9 Unit kHz
Symbol VTH
Description VDD-VCC threshold
Min 0.75
Typ 1.4
Max 1.75
Unit V
AMI Semiconductor www.amis.com
6
AMIS-70020 Power Failure Elapsed Time Counter
Power on Reset
Data Sheet
Symbol Vpor THreset TLreset Cut_off Switch
Min Typ Max 1.65 2.25 3.08 Value not testable Value not testable
Unit V
It is controlled by cut_off_ctrl when the comparator and filter have detected the loss of VCC, in this case the switch is OFF. Symbol Ron Description Resistance ON of the switch Min 250 Typ Max 500 Unit
Current Consumption Symbol IDD Description Min DC current in cut_off mode 0.1 No load at the pin Test_OUT, Q_OUT Typ 0.5 Max 1 Unit A
Revision Number Version 1.1
Changes on page
AMI Semiconductor www.amis.com
(c) Copyright 2003 AMI Semiconductor - All rights reserved. Information furnished is believed to be accurate and reliable. However, AMI Semiconductor assumes no responsibility for errors or omissions in the information and for the consequences of use of such information. AMI Semiconductor reserves the right to change the information contained herein at any time without notice. This information is provided "AS IS" without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability, fitness for a particular purpose, or non-infringement of intellectual property. All title and intellectual property rights including, without limitation, copyrights, trademarks, in and to this information and products are owned by AMI Semiconductor, and are protected by applicable laws. No license under any patent or other intellectual property of AMI Semiconductor is granted, by implication, estoppel or otherwise.

▲Up To Search▲

Price & Availability of AMIS-70020

	To Download AMIS-70020 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .