DATASHEET SEARCH SITE | WWW.ALLDATASHEET.COM
Document overview
- Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
- PDF pages: 12
Technical content
Specifications subject to change without notice - 1 - 3-phase Sensor-less Fan Motor Driver AM8919 The AM8919 is a 3-phase sensor-less DC fan motor driver IC. It senses the BEMF (Back Electro-Motive Force) of the motor in rotation and provides corresponding commutation current to the motor. Rotation speed can be controlled by PWM input signal. The drivers include Lock Detection, Thermal Shutdown, and Over-current limiter. Maximum output current is 1000mA. Features 1) Operation voltage 3.3 to 15V 2) Direct PWM speed control 3) Built-in FG & RD 4) Soft start function 5) Forward and Reverse control 6) Lock detection/Automatic restart function 7) Over current limiter 8) Over-voltage protection 9) Thermal shutdown protection 10) Soft switching technique to reduce acoustic noise Absolute Maximum Ratings (Ta = 25℃) Parameter Symbol Limits Unit Supply voltage V CC, VM 16 V VREG strength voltage V REG 6 V Output current Io 1000 mA FG & RD output voltage V FG & VRD Vcc V FG & RD output current I FG & IRD 10 mA PWM & F/R strength voltage V PWM &VFR V CC V CSOFT & OSC strength voltage V CSOFT & VOSC V REG V Power dissipation (JEDEC 2S2P) Pd 3790* mW Operate temperature range T opr -40～＋95 ℃ Storage temperature range T stg -55～＋150 ℃ Junction temperature Tjmax 150 ℃ * Pd de-rated by 30.32mW/C over 25℃ (based on JEDEC 2S2P board) Those are stress rating only and functional operating at those conditions for extended periods may damage to the device. Recommended operating conditions (Set the power supply voltage taking allowable dissipation into considering) Parameter Symbol Min Typ Max Unit Operating supply voltage range Vcc 3.3～15 V Storage Condition Parameter Value Unit Temperature condition Before Opening 5~40 ℃ Humidity condition Before Opening 30~80% RH Temperature condition after Opening <30 ℃ Humidity condition after Opening <60% RH
Specifications subject to change without notice - 2 - Electrical Characteristics (Unless otherwise specified, Ta = 25℃, VCC = 12.0V) Parameter Symbol Limit Unit Conditions Min Typ Max Supply current I CC － 1.8 3 mA PWM= V REG Stand-by current ISC － 0.6 1 mA PWM= 0V Regulator voltage VREG 2.85 3.0 3.15 V Oscillator OSC pin charge current I OSCC － -12 － μA OSC pin= 0.3V OSC pin discharge current I OSCD － 12 － μA OSC pin= 1.5V PWM, F/R input Input H level V PWMH/ VFRH 2.5 － V CC V Input L level V PWML/ VFRL 0 － 0.8 V PWM input frequency F PWM 20 － 50 kHz Output Output ON resistance R ON (H+L) － 1.5 2.1 Ω I 0=300mA High and Low total FG/RD low voltage V FGL/ VRDL － － 0.4 V I FG/RD = 3mA FG/RD leakage current I FGH/ IRDH － － 10 μA V FG/RD = 15V Lock protection Lock detection ON time T ON 0.7 1 1.3 sec T ON = start time + lock detect Lock detection OFF time T OFF 3.5 5 6.5 sec Soft start Soft start release voltage V CSOFT 1.5 2.0 2.5 V Soft start charge current I CSOFT － 0.5 － μA Current limiter Current limit voltage V RNF 0.2 0.25 0.3 V Thermal Thermal shutdown ThSD 150 170 － ℃ *1 Thermal shutdown hysteresis ΔThSD － 25 － ℃ *1 *1: It is design target, not to be measured at production test.
Specifications subject to change without notice - 3 - Block Diagram Fig.1 Block diagram Pin Description PIN No Pin Name Function PIN No Pin Name Function
1 CSOFT Soft start time setting terminal 10 NC No connection
2 F/R Forward and Reverse control terminal 11 W W phase output terminal
3 VREG Regulator voltage output terminal 12 V V phase output terminal
4 VCC Power supply terminal 13 NC No connection
5 VM Output supply terminal 14 GND Ground terminal
6 COM Motor center tap voltage input terminal 15 OSC Start-up frequency output terminal
7 U U phase output terminal 16 PWM PWM signal input terminal
8 NC No connection 17 FG FG signal output terminal
9 RNF output current detection terminal 18 RD RD signal output terminal
E-pad PG Power ground terminal
Specifications subject to change without notice - 4 - Application circuit Fig.2 Application circuit *1 Open drain output. A pull-up resistances of 10k Ω should be inserted. *2 This Capacitor 1000pF is only for reference. Variable Motors should select suitable capacitor for optimum start-up characteristics. *3 Current limiter voltage setting is 0.25V(Typ). The formula is RNF=0.25V/current limit target. (0.25Ω=0.25V/1A) *4 Need to add a 30 Ω resistor between Fan and IC Com Pin.
Specifications subject to change without notice - 5 - Thermal Information Θja junction-to-ambient thermal resistance 32.98℃/W Ψjt junction-to-top characterization parameter 0.82℃/W Θja is obtained in a simulation on a JEDEC-standard 2s2p board as specified in JESD-51. The Θja number listed above gives an estimate of how much temperature rise is expected if the device was mounted on a standard JEDEC board. When mounted on the actual PCB, the Θja value of JEDEC board is totally different than the Θja value of actual PCB. Ψjt is extracted from the simulation data to obtain Θja using a procedure described in JESD-51, which estimates the junction temperature of a device in an actual PCB. The thermal characterization parameter, Ψjt, is proportional to the temperature difference between the top of the package and the junction temperature. Hence, it is useful value for an engineer verifying device temperature in an actual PCB environment as described in JEDEC JESD-51-12. When Greek letters are not available, Ψjt is written Psi-jt. Definition: Where : Ψjt (Psi-jt) = Junction-to-Top(of the package) C/W Tj= Die Junction Temp. C Tt= Top of package Temp at center. C Pd= Power dissipation. Watts Practically, most of the device heat goes into the PCB, there is a very low heat flow through top of the package, So the temperature difference between Tj and Tt shall be small, that is any error caused by PCB variation is small. This constant represents that Ψjt is completely PCB independent and could be used to predict the Tj in the environment of the actual PCB if Tt is measured properly.
Specifications subject to change without notice - 6 - How to predict Tj in the environment of the actual PCB Step 1 : Used the simulated Ψjt value listed above. Step 2 : Measure Tt value by using Thermocouple Method We recommend use of a small ~40 gauge(3.15mil diameter) thermocouple. The bead and thermocouples wires should touch the top of the package and be covered with a minimal amount of thermally conductive epoxy. The wires should be heat-insulated to prevent cooling of the bead due to heat loss into wires. This is important towards preventing “too cool” Tt measurements, which would lead to the calculated Tj also being too cool. IR Spot Method An IR Spot method should be utilized only when using a tool with a small enough spot area to acquire the true top center “hot spot”. Many so-called “small spot size” tools still have a measurement area of 0~100+mils at “zero” distance of the tool from the surface. This spot area is too big for many smaller packages and likely would result in cooler readings than the small thermocouple method. Consequently, to match between spot area and package surface size is important while measuring Tt with IR sport method. Step 3 : calculating power dissipation by P (VCC–|Vo_Hi – Vo_Lo|) x Iout + VCC x Icc Step 4 : Estimate Tj value by Tj= Ψjt x P+Tt Step 5: Calculated Θja value of actual PCB by the known Tj Θja(actual) = (Tj-Ta)/P
Specifications subject to change without notice - 7 - Maximum Power Dissipation (de-rating curve) under JEDEC PCB & actual PCB
Specifications subject to change without notice - 8 - Operation notes 1) VCC power supply line The BEMF causes re-circulate current to power supply. Please connect a capacitor between power supply VCC pin and ground as a route of re-circulate current. And please determine the capacitance after confirmation that the capacitance does not causes any problems. 2) VM power supply line VM pin is U/V/W output transistors supply source. Please connect with VCC pin and short the path as possible. 3) VREG regulator VREG is voltage regulator output and internal circuits used. Connect capacitors to ground for stable operation. 4) Ground potential Ground potential E-PAD and GND pin connect the lowest voltage on the chip and short the path as possible. 5) PWM speed control This IC offer PWM pin direct control output transistors for motor speed control. Higher frequency will reduce output current noise. The control input frequency recommended operation between 20 KHz to 50 KHz. If frequency is slower than 7 KHz (typ.), it will go into stand-by mode. This pin connects internal pull-high resistance of 200K ohm to VREG. When connect to VREG or floating. The motor will rotate in the full speed. 6) Soft Switching Circuits This IC use duty-variable switching for low acoustic noise and vibration. 7) Start-up Circuits The OSC pin is defined a sensor-less start-up commutation frequency. The connecting capacitor is between the OSC pin and ground. Variable Motors start-up characteristic are variable with different capacitors. Variable Motors should select suitable capacitor for optimum start-up characteristics. If the capacitance value is larger, the variation start-up time is longer. Also, if the capacitance value is smaller, the motor start-up time is shorter and might cause start-up failed by fan friction. 8) FG / RD function This FG or RD pin is made up with an open drain output. Recommend connect a resistance of 10k ohm to supply. 9) Thermal design and Thermal shutdown The thermal design should allow enough margins for actual power dissipation. In case the IC is left running over the allowable loss, the junction temperature rises, and the thermal-shutdown circuit works at the junction temperature of 170°C (typ.) (the outputs of all the channels are turned off). When the junction temperature drops to 145°C (typ.), the IC start operating again. 10) F/R (Forward and Reverse) function Motor direction can be forward or reverse by switching F/R voltage level. F/R high (VREG): U -> V-> W and F/R low (ground): U->W->V. Internal pull low resistor is 100k ohms.
Specifications subject to change without notice - 9 - 11) Current limiter Current limiter voltage setting is 0.25V. Connect resistance to ground to determine the current limit value. The resistance path needs wider and ground side make shorter to GND. The formula is RNF=0.25V/current limit target. (0.25Ω=0.25V/1A) 12) Soft start function The motor could be smoothly start-up when Soft start pin connecting a capacitor to ground. The function release when the voltage reaches 2.0V or more. If the soft start function is not used, keeps this pin floating.
Specifications subject to change without notice - 10 - Packaging outline --- DFN 4x4 Unit : mm reference JEDEC MO229(D)VJGD-2 SYMBOL MILLIMETERS INCHES Min. Max. Min. Max. A - 0.90 - 0.035 A1 - 0.05 - 0.002 A2 - 0.70 - 0.028 A3 0.20 REF 0.008 REF b 0.15 0.27 0.006 0.011 D 4.00 BSC 0.157 BSC E 4.00 BSC 0.157 BSC D2 3.45 3.55 0.136 0.140 E2 2.35 2.45 0.093 0.096 L 0.35 0.45 0.014 0.018 e 0.4 BSC 0.016 BSC
Specifications subject to change without notice - 11 - Condition of Soldering 1). Manual Soldering Time / Temperature ＜ 3 sec / 400 + 10 oC （1 Cycle） Test Results：0 fail/ 22 tested Manual Soldering count：2 Times 2). Re-flow Soldering (follow IPC/JEDEC J-STD-020D) Classification Reflow Profile Profile Feature Pb-Free Assembly Average ramp-up rate (TL to TP) 3 oC/second max. Preheat - Temperature Min (Ts min) - Temperature Max (Ts max) - Time (ts) from (Tsmin to Tsmax) 150 oC 200oC 60-120 seconds Ts max to TL - Temperature Min (Ts min) 3oC/second max. Time maintained above: - Liquid us temperature (TL) - Time (tL) maintained above TL 217oC 60-150 seconds Peak package body temperature (Tp) 260 +0/-5 oC Time with 5oC of actual Peak - Temperature (tp) 30 seconds Ramp-down Rate 6 oC/second max. Time 25oC to Peak Temperature 8 minutes max. Test Results：0 fail/ 32 tested Reflow count ：3 cycles
Specifications subject to change without notice - 12 - Marking Identification Row 1 A8919 Row 2 Lot number & Date Row 1 Row 2