ADT7421

ADT7421 ONSEMI | Alldatasheet

Document overview

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Technical content

Features

• On−Chip and Remote Temperature Sensor
• 0.25°C Resolution on Remote Channel
• 1°C Resolution on Local Channel
• Automatically Cancels the Effect of Beta Variation in Thermal Transistors on Small Geometry CPU’s
• Automatically Cancels Up to 50 /C0087 (Typical) of Resistance in Series with Remote Transistor
• Extended, Switchable Temperature Measurement Range 0°C to +125°C (default) or −40°C to +125°C
• Pin− and Register−Compatible with ADM1032, ADT7461, ADT7461A, EMC1402, and aSC7525
• 2−Wire SMBus Serial Interface with SMBus Alert Support
• Programmable Over/Undertemperature Limits
• Offset Registers for System Calibration
• Up to Two Overtemperature Fail−Safe THERM Outputs
• Small 8−lead MSOP and SOP Packages
• These are Pb−Free Devices

Applications

• Desktop and Notebook Computers
• Industrial Controllers
• Smart Batteries
• Automotive
• Embedded Systems
• Burn−In Applications
• Instrumentation http://onsemi.com PIN ASSIGNMENT VDD GND ALERT/THERM2 THERM (Top View) SCLK SDATA See detailed ordering and shipping information in the package dimensions section on page 18 of this data sheet.

ORDERING INFORMATION

MSOP−8 CASE 846AB SOIC−8 CASE 751 T7421 ALYWR/C0071 /C0071 L7x = Refer to Ordering Table A = Assembly Location Y = Year W = Work Week /C0071= Pb−Free Package L7x AYW/C0071 /C0071 (Note: Microdot may be in either location) A = Assembly Location L = Wafer Lot Y = Year W = Work Week R = SMBus Address /C0071= Pb−Free Package

temperature sensing on 45 nm CPU’s and GPU’s. extended, switchable temperature measurement range. ADT7421 is used on the same SMBus. Figure 1. Block Diagram 1 VDD Positive Supply, 3.0 V to 3.6 V. overtemperature condition. Requires pullup resistor. 5 GND Supply Ground Connection. second THERM output. Requires pullup resistor. 7 SDATA Logic Input/Output, SMBus Serial Data. Open-Drain Output. Requires pullup resistor. 8 SCLK Logic Input, SMBus Serial Clock. Requires pullup resistor.

NOTE: This device is ESD sensitive. Use standard ESD precautions when handling.

1. Guaranteed by design, but not production tested.
2. Time from 10% of SDATA to 90% of SCLK.
3. Time for 10% or 90% of SDATA to 10% of SCLK.
4. Time for 90% of SCLK to 10% of SDATA.

Figure 2. Serial Bus Timing

http://onsemi.com ELECTRICAL CHARACTERISTICS (TA = −40°C to +125°C, VDD = 3.0 V to 3.6 V, unless otherwise noted) Parameter Conditions Min Typ Max Unit Power Supply Supply Voltage, VDD 3.0 3.30 3.6 V Average Operating Supply Current, IDD 0.0625 Conversions/Sec Rate (Note 1) 3.0 4.0 mA Standby Mode Supply Current −40°C ≤ TA ≤ +85°C /C0109A Power-On-Reset Threshold 1.0 2.8 V Temperature−To−Digital Converter Local Sensor Accuracy 0°C ≤ TA ≤ +125°C ±2.75 °C Resolution 1.0 °C Remote Transistor Sensor Accuracy +40°C ≤ TA ≤ +85°C, +60°C ≤ TD ≤ +110°C (Note 2) +25°C ≤ TA ≤ +85°C, +60°C ≤ TD ≤ +110°C (Note 2) TA = +40°C, +60°C ≤ TD ≤ +110°C (Note 2) ±2.5 ±3.25 ±1.75 Resolution 0.25 °C Remote Sensor Source Current The range of source currents provided to the external thermal transistor for temperature measurements. 10 to 360 /C0109A Conversion Time From stop bit to conversion complete, one-shot mode with averaging switched on. One-shot mode with averaging off. 184 ms Maximum Series Resistance Cancelled Resistance split evenly on both the D+ and D– inputs. 50 /C0087 Open−Drain Digital Outputs (THERM, ALERT/THERM2, SDA) Output Low Voltage, VOL IOUT = −6.0 mA 0.2 V High Level Output Leakage Current, IOH VOUT = VDD 0.1 1.0 /C0109A SMBus Interface (Note 3) Logic Input High Voltage, VIH SCL, SDA 3.0 V ≤ VDD ≤ 3.6 V 2.1 V Logic Input Low Voltage, VIL SCL, SDA 3.0 V ≤ VDD ≤ 3.6 V 0.8 V Hysteresis 500 mV SDA Output Low Voltage, VOL IOUT = −6.0 mA 0.4 V Logic Input Current, IIH, IIL −1.0 +1.0 /C0109A SMBus Input Capacitance, SCLK, SDATA 10 pF SMBus Clock Frequency 400 kHz SMBus Timeout (Note 4) User programmable 25 300 ms SCLK Falling Edge to SDATA Valid Time Master clocking in data 1.0 /C0109s 1. See Table 4 for information on other conversion rates. 2. Guaranteed by characterization, but not production tested. 3. See SMBus Timing Specifications section for more information. 4. Disabled by default. Detailed procedures to enable it are in the Serial Bus Interface section of this datasheet.

http://onsemi.com Theory of Operation The ADT7421 is a local and remote temperature sensor and over/undertemperature alarm, with the added ability to automatically cancel the effect of beta variations in embedded thermal transistors in small geometry CPU’s. When the ADT7421 is operating normally, the on −board ADC operates in a free running mode. The analog input multiplexer alternately selects either the on −chip temperature sensor to measure its local temperature or the remote temperature sensor. The ADC digitizes these signals and the results are stored in the local and remote temperature value registers. The local and remote measurement results are compared with the corresponding high, low, and THERM temperature limits, stored in eight on −chip registers. Out −of−limit comparisons generate flags that are stored in the status register. A result that exceeds the high temperature limit or the low temperature limit causes the ALERT output to assert. The ALERT output also asserts if an external transistor fault is detected. Exceeding the THERM temperature limits causes the THERM output to assert low. The ALERT output can be reprogrammed as a second THERM output. The limit registers are programmed and the device controlled and configured via the serial SMBus. The contents of any register are also read back via the SMBus. Control and configuration functions consist of switching the device between normal operation and standby mode, selecting the temperature measurement range, masking or enabling the ALERT output, switching Pin 6 between ALERT and THERM2, and selecting the conversion rate. Beta Variation Cancellation The ADT7421 includes a new temperature sensing method which cancels out the effect of varying Beta factors being observed when different currents are applied to the embedded thermal transistor in small geometry processes. This method also ensure consistent and accurate temperature measurements between CPU’s. Series Resistance Cancellation Parasitic resistance to the D+ and D − inputs to the ADT7421, seen in series with the remote transistor, is caused by a variety of factors, including PCB track resistance and track length. This series resistance appears as a temperature offset in the remote sensor’s temperature measurement. This error typically causes a 0.5°C offset per ohm of parasitic resistance in series with the remote transistor. The ADT7421 automatically cancels the effect of this series resistance on the temperature reading, giving a more accurate result, without the need for user characterization of this resistance. The ADT7421 is designed to automatically cancel typically up to 50 /C0087 of resistance. By using an advanced temperature measurement method, this process is transparent to the user. Temperature Measurement Method A simple method of measuring temperature is to exploit the negative temperature coefficient of a transistor, measuring the base emitter voltage (V BE) of a transistor operated at constant current. However, this technique requires calibration to null the effect of the absolute value of V BE, which varies from device to device. The technique used in the ADT7421 measures the change in VBE when the device operates at three different currents. Previous devices used only two operating currents, but it is the use of a third current that allows automatic cancellation of resistances in series with the external temperature sensor. Figure 9 shows the input signal conditioning used to measure the output of an external temperature sensor. This figure shows the external sensor as a substrate transistor, but it can equally be a discrete transistor. If a discrete transistor is used, the collector is not grounded but is linked to the base. To prevent ground noise interfering with the measurement, the more negative terminal of the sensor is not referenced to ground, but is biased above ground by an internal transistor at the D − input. C1 may be added as a noise filter (a recommended maximum value of 2200 pF). To measure /C0068V BE, the operating current through the sensor is switched among three related currents. As shown in Figure 9, N1 × I and N2 × I are different multiples of the current, I. The currents through the temperature transistor are switched between I and N1 × I, giving V BE1; and then between I and N2 × I, giving /C0068VBE2. The temperature is then calculated using the two /C0068VBE measurements. This method also cancels the effect of any series resistance on the temperature measurement. The resulting /C0068V BE waveforms are passed through a 65 kHz low −pass filter to remove noise and then to a chopper−stabilized amplifier. This amplifies and rectifies the waveform to produce a dc voltage proportional to /C0068VBE. The ADC digitizes this voltage producing a temperature measurement. To reduce the effects of noise, digital filtering is performed by averaging the results of 16 measurement cycles for low conversion rates. At rates of 10, 20, and 36 conversions per second, no digital averaging occurs. Signal conditioning and measurement of the internal temperature sensor are performed in the same manner.

Figure 9. Input Signal Conditioning CAPACITOR C1 IS OPTIONAL. IT IS ONLY NECESSARY IN NOISY ENVIRONMENTS. C1 = 1000pF MAX. the local and remote high and low limit registers. lists the data format for the external temperature low byte. Table 1. Extended Temperature Resolution external measurements is, by default, 0 °C to +125 °C. temperatures from −40°C to +125°C. data format is used for both internal and external results. are shown in the following table. Table 2. Temperature Data Format

1. Offset binary scale temperature values are offset by 64 °C.
2. Binary scale temperature measurement returns 0 °C for all
3. Binary scale temperature measurement returns 125°C for all

time. Switching the range likewise switches the data format. on this is found in the Limit Registers section. register map is available in Table 8. because its register address is 0x00. register is at Address 0x00. Address 0x01, with the low byte register at Address 0x10. The power−on default for all three registers is 0x00. and Bit 3 are reserved; the user does not write to them. disabled. This applies only if Pin 6 is configured as ALERT. outputs cause these signals to be updated. be switched off by setting Bit 4 to 1. up as a THERM2 output, then Bit 7 has no effect. Table 3. Configuration Register Bit Assignments

7 MASK1 0 = ALERT Enabled

6 RUN/STOP 0 = Run

5 ALERT/

4 Beta Enable 0 = Beta Compensation

3 Reserved Reserved 1

2 Temperature

1 Reserved Reserved 0

0 Reserved Reserved 0

Table 4. Conversion Rate Register Codes limit register addresses and their power−on default values. measuring 0°C or lower results in an out−of−limit condition. however, the temperature limits do not automatically switch. to be reprogrammed to 0100 1010b. The status register is a read−only register at Address 0x02. It contains status information for the ADT7421. Bit 1 to Bit 0) and the remote sensor open circuit (Bit 2). interrupt latch is set and the ALERT output goes low. measurement or if the sensor is good. temperature falls to limit value minus the hysteresis value. behavior of THERM2 is otherwise the same as THERM. Table 5. Status Register Bit Assignments

7 BUSY 1 when ADC Converting

6 LHIGH* 1 when Local High Temperature Limit Tripped

5 LLOW* 1 when Local Low Temperature Limit Tripped

4 RHIGH* 1 when Remote High Temperature Limit

3 RLOW* 1 when Remote Low Temperature Limit

2 OPEN* 1 when Remote Sensor Open Circuit

1 RTHRM 1 when Remote THERM Limit Tripped

0 LTHRM 1 when Local THERM Limit Tripped

and has no effect unless the user writes a different value to it. Table 6. Sample Offset Register Codes address is irrelevant and is not stored. no averaging takes place. This register is at Address 0x22. Table 7. Consecutive ALERT Register 0x22

Table 8. List of Registers

00 Not Applicable Local Temperature Value 0000 0000 0x00

01 Not Applicable External Temperature Value High Byte 0000 0000 0x00

02 Not Applicable Status Undefined

10 Not Applicable External Temperature Value Low Byte 0000 0000 0x00

Control of the ADT7421 is carried out via the serial bus. under the control of a master device. activity. However, this feature is not enabled by default. (Address = 0x22) should be set to enable it. over the bus, the slave device with that address responds. (1001 100b). The ADT7421−2 is also available.

1. Data is sent over the serial bus in a sequence of

• If the address pointer register value of the ADT7421 is unknown or not the desired value, it is first necessary to set it to the correct value before data can be read from the desired data register. This is done by writing to the ADT7421 as before, but only the data byte containing the register read address is sent, because data is not to be written to the register (see Figure 11). A read operation is then performed consisting of the serial bus address, R/W bit set to 1, followed by the data byte read from the data register (see Figure 12).
• If the address pointer register is known to be at the desired address, data can be read from the corresponding data register without first writing to the address pointer register and the bus transaction shown in Figure 11 can be omitted. Notes
• It is possible to read a data byte from a data register without first writing to the address pointer register. However, if the address pointer register is already at the correct value, it is not possible to write data to a register without writing to the address pointer register because the first data byte of a write is always written to the address pointer register.
• Some of the registers have different addresses for read and write operations. The write address of a register must be written to the address pointer if data is to be written to that register, but it may not be possible to read data from that address. The read address of a register must be written to the address pointer before data can be read from that register. ALERT Output This is applicable when Pin 6 is configured as an ALERT output. The ALERT output goes low whenever an out−of−limit measurement is detected, or if the remote temperature sensor is open circuit. It is an open−drain output and requires a pullup resistor. Several ALERT outputs can be wire−OR’ed together, so that the common line goes low if one or more of the ALERT outputs goes low. The ALERT output can be used as an interrupt signal to a processor, or as an SMBALERT. Slave devices on the SMBus cannot normally signal to the bus master that they want to talk, but the SMBALERT function allows them to do so. One or more ALERT outputs can be connected to a common SMBALERT line that is connected to the master. When the SMBALERT line is pulled low by one of the devices, the following procedure occurs (see Figure 13):

Figure 13. Use of SMBALERT

1. Master initiates a read operation and sends the
2. If more than one device’s ALERT

consumption in the standby mode is reduced to 10 /C0109A. even though the ADT7421 is still in standby. continuous setting of the open flag.

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• When the THERM2 limit is exceeded, the THERM2 signal asserts low.
• If the temperature continues to increase and exceeds the THERM limit, the THERM output asserts low.
• The THERM output de−asserts (goes high) when the temperature falls to THERM limit minus hysteresis. In Figure 15, there is no hysteresis value shown.
• As the system cools further, and the temperature falls below the THERM2 limit, the THERM2 signal resets. Again, no hysteresis value is shown for THERM2. Both the external and internal temperature measurements cause THERM and THERM2 to operate as described.

Application Information

The ADT7421 is designed to work with substrate transistors built into processors or with discrete transistors. Substrate transistors are generally PNP types with the collector connected to the substrate. Discrete types are either PNP or NPN transistors c onnected as transistors (base−shorted to collector). If an NPN transistor is used, the collector and base are connected to D+ and the emitter to D−. If a PNP transistor is used, the collector and base are connected to D − and the emitter to D+. Note that Beta Cancellation should be turned OFF when using a discrete transistor. This is done by setting Bit 4 of the Configuration Register to 1. To reduce the error due to variations in both substrate and discrete transistors, consider several factors:

• The ideally factor, nF, of the transistor is a measure of the deviation of the thermal transistor from ideal behavior. The ADT7421 is trimmed for an nF value of 1.008. The following equation may be used to calculate the error introduced at a temperature, T (°C), when using a transistor whose n F does not equal 1.008. Consult the processor data sheet for the nF values. /C0068T /C0043(nr /C00421.008)/C03241.008 /C0032(273.15 Kelvin /C0041T) To factor this in, the user writes the /C0068T value to the offset register. It is then automatically added to, or subtracted from, the temperature measurement.
• Some CPU manufacturers specify the high and low current levels of the substrate transistors. The high current level of the ADT7421, IHIGH, is 220 /C0109A and the low level current, ILOW, is 13.5 /C0109A. If the ADT7421 current levels do not match the current levels specified by the CPU manufacturer, it may become necessary to remove an offset. The CPU data sheet should advise whether this offset needs to be removed and how to calculate it. This offset is programmed to the offset register. It is important to note that if more than one offset must be, considered, the algebraic sum of these offsets must be programmed to the offset register. If a discrete transistor is used with the ADT7421, the best accuracy is obtained by choosing devices according to the following criteria:
• Base−emitter voltage greater than 0.25 V at 6 /C0109A, at the highest operating temperature
• Base−emitter voltage less than 0.95 V at 100 /C0109A, at the lowest operating temperature
• Base resistance less than 100 /C0087
• Small variation in hFE (50 to 150) that indicates tight control of VBE characteristics Transistors, such as the 2N3904, 2N3906, or equivalents in SOT−23 packages are suitable devices to use. Thermal Inertia and Self−Heating Accuracy depends on the temperature of the remote sensing transistor and/or the internal temperature sensor being at the same temperature as that being measured. Many factors can affect this. Ideally, place the sensor in good thermal contact with the part of the system being measured. If it is not, the thermal inertia caused by the sensor’s mass causes a lag in the response of the sensor to a temperature change. In the case of the remote sensor, this should not be a problem since it is either a substrate transistor in the processor or a small package device, such as the SOT −23, placed in close proximity to it. The on−chip sensor, however, is often remote from the processor and only monitors the general ambient temperature around the package. How accurately the temperature of the board and/or the forced airflow reflects the temperature to be measured dictates the accuracy of the measurement. Self−heating due to the power dissipated in the ADT7421 or the remote sensor causes the chip temperature of the device or remote sensor to rise above ambient. However, the current forced through the remote sensor is so small that self−heating is negligible. In the case of the ADT7421, the worst−case condition occurs when the device is converting at 36 conversions per second while sinking the maximum current of 1 mA at the ALERT and THERM output. In this case, the total power dissipation in the device is about 4.5 mW. The thermal resistance, /C0068JA, of the 8−lead MSOP is approximately 142°C/W. Layout Considerations Digital boards can be electrically noisy environments, and the ADT7421 is measuring very small voltages from the remote sensor, so care must be taken to minimize noise induced at the sensor inputs. Take the following precautions:
• Place the ADT7421 as close as possible to the remote sensing transistor. Provided that, the worst noise sources, that is, clock generators, data/address buses, and CRT’s are avoided, this distance can be 4 to 8 inches.
• Route the D+ and D− tracks close together, in parallel, with grounded guard tracks on each side. To minimize

plane under the tracks, if possible. Figure 16. Typical Arrangement of Signal Tracks

• Try to minimize the number of copper/solder joints that can cause thermocouple effects. Where copper/solder joints are used, make sure that they are in both the D+ and D− path and at the same temperature.
• Thermocouple effects should not be a major problem as 1°C corresponds to about 200 mV , and thermocouple voltages are about 3 mV/°C of temperature difference. Unless there are two thermocouples with a big temperature differential between them, thermocouple voltages should be much less than 200 mV .
• Place a 0.1 /C0109F bypass capacitor close to the VDD pin. In extremely noisy environments, place an input filter capacitor across D+ and D− close to the ADT7421. This capacitance can effect the temperature measurement, so ensure that any capacitance seen at D+ and D− is, at maximum, 2200 pF. This maximum value includes the filter capacitance, plus any cable or stray capacitance between the pins and the sensor transistor.
• If the distance to the remote sensor is more than 8 inches, the use of twisted pair cable is recommended. A total of 6 feet to 12 feet is needed. For really long distances (up to 100 feet), use a shielded twisted pair, such as the Belden No. 8451 microphone cable. Connect the twisted pair to D+ and D − and the shield to GND close to the ADT7421. Leave the remote end of the shield unconnected to avoid ground loops. Because the measurement technique uses switched current sources, excessive cable or filter capacitance can affect the measurement. When using long cables, the filter capacitance can be reduced or removed. Application Circuit Figure 17 shows a typical application circuit for the ADT7421, using a discrete sensor transistor connected via a shielded, twisted pair cable. The pull −ups on SCLK, SDATA, and ALERT are required only if they are not provided elsewhere in the system.

Figure 17. Typical Application Circuit Table 10. Status/Configuration Registers

Table 11. Configuration Register; Read Address 0x03, Write Address 0x09 enabled. This applies only if Pin 8 is configured as ALERT, otherwise it has no effect.

6 Run/STOP R/W Setting this Bit to 1 places the ADT7421 in standby mode (that is, it suspends all

configures Pin 8 as THERM2 pin.

3 Reserved Read only Reserved

1 Reserved Read only Reserved

0 Reserved Read only Reserved

Table 12. Conversion Rate Register (Read Address = 0x04, Write Address = 0x0A)

7 Reserved Reserved

6 Reserved Reserved

5 Reserved Reserved

4 Reserved Reserved

Table 13. Status Register; (Read Address = 0x02)

7 BUSY 1 when ADC converting No

6 LHIGH (Note 1) 1 when local high temperature limit tripped Yes

5 LLOW (Note 1) 1 when local low temperature limit tripped Yes

4 RHIGH (Note 1) 1 when Remote 1 high temperature limit tripped Yes

3 RLOW (Note 1) 1 when Remote 1 low temperature limit tripped Yes

2 D OPEN (Note 1) 1 when Remote 1 sensor open circuit Yes

1 RTHRM 1 when Remote 1 THERM limit is tripped No

0 LTHRM 1 when local THERM limit is tripped No

1. These flags stay high until the status register is read, or they are reset by POR

http://onsemi.com Table 14. Consecutive ALERT Register (Read Address = 0x22, Write Address = 0x22) Table 15. Value Registers Table 16. Limit Registers Device Order Number* Package Type Part Marking SMBus Address Shipping† ADT7421ARZ-REEL 8-Lead SOIC_N T7421 4C 2500 Tape & Reel ADT7421ARZ-REEL7 8-Lead SOIC_N T7421 4C 1000 Tape & Reel ADT7421ARMZ-REEL 8-Lead MSOP L75 4C 3000 Tape & Reel ADT7421ARMZ-RL7 8-Lead MSOP L75 4C 1000 Tape & Reel ADT7421ARMZ-2RL 8-Lead MSOP L76 4D 3000 Tape & Reel ADT7421ARMZ-2RL7 8-Lead MSOP L76 4D 1000 Tape & Reel †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D. *The “Z’’ suffix indicates Pb−Free package.

http://onsemi.com PACKAGE DIMENSIONS SEATING PLANE N J X 45/C0095 K NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: MILLIMETER. 3. DIMENSION A AND B DO NOT INCLUDE MOLD PROTRUSION. 4. MAXIMUM MOLD PROTRUSION 0.15 (0.006) PER SIDE. 5. DIMENSION D DOES NOT INCLUDE DAMBAR PROTRUSION. ALLOWABLE DAMBAR PROTRUSION SHALL BE 0.127 (0.005) TOTAL IN EXCESS OF THE D DIMENSION AT MAXIMUM MATERIAL CONDITION. 6. 751 −01 THRU 751−06 ARE OBSOLETE. NEW STANDARD IS 751−07. A B S DH C 0.10 (0.004) DIM A MIN MAX MIN MAX INCHES 4.80 5.00 0.189 0.197 MILLIMETERS B 3.80 4.00 0.150 0.157 C 1.35 1.75 0.053 0.069 D 0.33 0.51 0.013 0.020 G 1.27 BSC 0.050 BSC H 0.10 0.25 0.004 0.010 J 0.19 0.25 0.007 0.010 K 0.40 1.27 0.016 0.050 M 0 8 0 8 N 0.25 0.50 0.010 0.020 S 5.80 6.20 0.228 0.244 −X− −Y− G MYM0.25 (0.010) −Z− YM0.25 (0.010) Z S X S M /C0095/C0095/C0095/C0095 1.52 0.060 7.0 0.275 0.6 0.024 1.270 0.050 4.0 0.155 /C0466mm inches/C0467SCALE 6:1 *For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. SOLDERING FOOTPRINT* SOIC−8 NB CASE 751−07 ISSUE AJ

http://onsemi.com PACKAGE DIMENSIONS SBM0.08 (0.003) A ST NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: MILLIMETER. 3. DIMENSION A DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.15 (0.006) PER SIDE. 4. DIMENSION B DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSION. INTERLEAD FLASH OR PROTRUSION SHALL NOT EXCEED 0.25 (0.010) PER SIDE. 5. 846A-01 OBSOLETE, NEW STANDARD 846A-02. b ePIN 1 ID 8 PL 0.038 (0.0015) −T− SEATING PLANE A A1 c L DIM A MIN NOM MAX MIN MILLIMETERS INCHES A1 0.05 0.08 0.15 0.002 b 0.25 0.33 0.40 0.010 c 0.13 0.18 0.23 0.005 D 2.90 3.00 3.10 0.114 E 2.90 3.00 3.10 0.114 e 0.65 BSC L 0.40 0.55 0.70 0.016 −− 0.043 0.003 0.006 0.013 0.016 0.007 0.009 0.118 0.122 0.118 0.122

0.026 BSC

0.021 0.028 NOM MAX HE DD E MSOP8 CASE 846AB−01 ISSUE O *For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. SOLDERING FOOTPRINT* 8X 8X 6X /C0466mm inches/C0467SCALE 8:1 1.04 0.041 0.38 0.015 5.28 0.208 4.24 0.167 3.20 0.126 0.65 0.0256 ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, direct ly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner. PUBLICATION ORDERING INFORMATION N. American Technical Support: 800−282−9855 Toll Free USA/Canada Europe, Middle East and Africa Technical Support: Phone: 421 33 790 2910 Japan Customer Focus Center Phone: 81−3−5773−3850 ADT7421/D Protected by US Patents 5,195,827; 5,867,012; 5,982,221; 6,097,239; 6,133,753; 6,169,442; 7,010,440; other patents pending. LITERATURE FULFILLMENT: Literature Distribution Center for ON Semiconductor P.O. Box 5163, Denver, Colorado 80217 USA Phone: 303−675−2175 or 800−344−3860 Toll Free USA/Canada Fax: 303−675−2176 or 800−344−3867 Toll Free USA/Canada Email: orderlit@onsemi.com ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative