View AAT4900_973661.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

Buffered Power Half-Bridge General Description
The AAT4900 FastSwitchTM is a member of AnalogicTechTM's Application Specific Power MOSFETTM (ASPMTM) product family. It is a Buffered Power Half-Bridge, consisting of low onresistance Power MOSFETs with integrated control logic. This device operates with inputs ranging from 2.7V to 5.5V, making it ideal for both 3V and 5V systems. The device is protected from shootthrough current with its own control circuitry. The AAT4900 is capable of very fast switching times and is ideal for use in high frequency DC to DC Converters. The quiescent supply current is a low 4mA at 1MHz CLK frequency. In shutdown mode, the supply current decreases to less than 1A max. The AAT4900 is available in 5 pin SOT-23 or 8 pin SC70JW specified over -40 to 85C.
AAT4900
Features
* * * * * * * *
FastSwitchTM
2.7V to 5.5V Input voltage range 105m (typ) Low Side Switch RDS(ON) 130m (typ) High Side Switch RDS(ON) Low quiescent current * 1A (max) DC * 4mA at 1MHz Only 2.5V needed for Control Signal Input Break before make shoot-thru protection Temp range -40 to 85C 5 pin SOT-23 or 8 pin SC70JW package
Applications
* * * High frequency DC/DC converters MOSFET Driver DC Motor Drive
Typical Applications
DC/DC Converter Output Stage
2.7V to 5.5V Input
IN
Control Circuit (PWM Output)
CLK EN
AAT4900
SOT-23 GND
OUTPUT LX
ENABLE
4900.2004.04.1.0
1
Buffered Power Half-Bridge Pin Descriptions
Pin #
SOT23-5 1 2 3 4 5 SC70JW-8 2, 3 6, 7, 8 4 5 1
AAT4900
Symbol
LX GND EN CLK IN
Function
Inductor connection. LX output is controlled by CLK and EN(see Control Logic Table). Ground connection Active-high Enable input. A logic low signal puts the LX output pin in high impedance mode. Logic input signal determines the state of LX output. Supply voltage input. Input voltage range from 2.7V to 5.5V.
Pin Configuration
SOT23-5 (Top View) SC70JW-8 (Top View)
LX GND EN
1 2 3
5
IN CLK
4
IN LX LX EN
1 2
8 7
3 4
6 5
GND GND GND CLK
1 2
Control Logic Table
Inputs CLK
0 0 1 1
Output EN
0 1 0 1
LX
High impedance VIN High impedance Ground
2
4900.2004.04.1.0
Buffered Power Half-Bridge Absolute Maximum Ratings
Symbol
VIN VEN, VCLK VOUT IMAX TJ VESD TLEAD
AAT4900
(TA=25C unless otherwise noted) Value
-0.3 to 6 -0.3 to VIN+0.3 -0.3 to VIN+0.3 2 -40 to 150 4000 300
Description
IN to GND EN, CLK to GND OUT to GND Maximum Continuous Switch Current Operating Junction Temperature Range ESD Rating 1 - HBM Maximum Soldering Temperature (at Leads)
Units
V V V A C V C
Note: Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum rating should be applied at any one time. Note 1: Human body model is a 100 pF capacitor discharged through a 1.5k resistor into each pin.
Thermal Information
Symbol
JA PD
Description
Thermal Resistance 2 (SOT23-5, SC70JW-8) Power Dissipation 2 (SOT23-5, SC70JW-8)
Value
190 526
Units
C/W mW
Note 2: Mounted on a demo board.
Electrical Characteristics
are at TA=25C) Symbol
VIN IQAC IQDC IQ(OFF) ISD(OFF) RDS(ON)H RDS(ON)L VONL VONH ISINK TBBM TON-DLY THIZ
(VIN = 5V, TA = -40 to 85C unless otherwise noted. Typical values Conditions Min
2.7 4
Description
Operation Voltage AC Quiescent Current DC Quiescent Current Off-Supply Current Off-Switch Current High Side MOSFET On Resistance Low Side MOSFET On Resistance CLK, EN Input low Voltage
Typ
Max
5.5 9 1 1 1 165 195 145 175 0.8
Units
V mA A A A m m m m V V V A ns ns ns ns ns ns
IN = 5V, EN = IN, CLK = 1MHz, ILX = 0 IN = 5V, EN = IN,CLK = GND, ILX = 0 EN = CLK = GND IN = LX = 5.5V EN = GND, IN = 5.5V, VOUT=0, or LX = IN IN = 5.0V, TA = 25C IN = 3.0V, TA = 25C IN = 5.0V, TA = 25C IN = 3.0V, TA = 25C IN = 2.7V to 5.5V IN = 2.7V to 4.2V 3 CLK, EN Input High Voltage IN = >4.2V to 5.0V 3 CLK, EN Input leakage CLK, EN = 5.5v CLK rising Break Before Make Time CLK falling CLK rising CLK to LX delay CLK falling CLK = GND EN to OUT HiZ delay CLK = IN
0.03 130 165 105 135 2.0 2.4 0.01 5 5 30 40 40 40
1
Note 3: For VIN outside this range consult CLK/Enable Threshold vs. Input Voltage curve. 4900.2004.04.1.0
3
Buffered Power Half-Bridge Typical Characteristics
Operating Current vs. Input Voltage Fs=1MHz
Operating Current (mA)
6 5 4 3 2 1 0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
AAT4900
Operating Current vs. Switching Frequency
10.000 1.000 0.100 0.010 0.001 0.000 0.0
Operating Current (mA)
7
VIN=5V VIN=3V
0.1
1.0
10.0
100.0
1000.0
10000.0
V IN (V)
Frequency (kHz)
Operating Current vs. Temperature Fs=1MHz
Operating Current (mA) Operating Current (mA)
12 10 8 6 4 2 0 -40
2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0
Operating Current vs. Temperature Fs=1MHz
VIN = 3.1V
VIN = 5.5V
VIN = 2.7V
VIN = 4.3V
-20 0 20 40 60 80 100 120
-40
-20
0
20
40
60
80
100
120
Temperature (C)
Temperature (C)
High Side Rds(on) vs. Output Current
0.22 0.21 0.20 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.10 0.20
Low Side R ds(on) vs. Output Current
0.16
VIN = 2.7V Rds(on) ()
0.15 0.14 0.13 0.12 0.11 0.10
VIN = 2.7V
Rds(on) ()
VIN = 5.5V
0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20
0.09 0.08 0.2
VIN = 5.5V
0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2
Output Current (A)
Output Current (A)
4
4900.2004.04.1.0
Buffered Power Half-Bridge Typical Characteristics
High Side Rds(on)
0.30 0.30 0.25 0.25 0.20
AAT4900
Low Side Rds(on)
Rds(on) ()
Rds(on) ()
0.20 0.15 0.10 0.05 0.00 -40
VIN = 2.7V, ID = 2.2A
0.15 0.10 0.05 0.00
VIN = 2.7V, ID = 2.2A VIN = 2.7V, ID = 0.2A
80 100 120
VIN = 5.5V, ID = 0.2A to 2.2A
-20 0 20 40 60
VIN = 2.7V, ID = 0.2A
VIN = 5.5V, ID = 0.2A to 2.2A
-40 -20 0 20 40 60
80
100
120
Temperature (C)
Temperature (C)
Propagation Delay vs. Input Voltage CL=1000pF
Threshold Voltage (V)
70
CLK/Enable Threshold vs. Input Voltage
2.4 2.2 2 1.8 1.6 1.4 1.2 1 0.8 0.6 2.5 3 3.5 4 4.5 5 5.5
Delay Time (ns)
60 50 40 30 20 10 0 2.5 3 3.5 4 4.5 5 5.5
tPLH
VONH
tPHL
VONL
VIN (V)
Input Voltage (V)
Rds(on) vs. Input Voltage
0.19 0.18 0.17
Rds(on) ()
0.16 0.15 0.14 0.13 0.12 0.11 0.1 2.5 3 3.5 4 4.5 5 5.5
High Side
Low Side
Input Voltage (V)
4900.2004.04.1.0
5
Buffered Power Half-Bridge Functional Block Diagram
IN
AAT4900
CLK
Control Logic and Shoot-through Protection
LX
EN
GND
Typical Applications
DC-DC Converter
The most common AAT4900 applications include a DC-DC converter output power stage and a MOSFET gate drive buffer. Figure 1 shows a common configuration when used as a DC-DC converter power stage with synchronous rectification. The enable pin can be used to
VIN = 2.7 to 5.5V
force the LX output to a high impedance state under light load conditions. This enables the output inductor to operate in discontinuous conduction mode (DCM), improving efficiency under light load conditions. The body diode associated with the low side switching device gives the AAT4900 inductive switching capability, clamping the LX node at a diode drop below GND during the break before make time.
IN EN DC -DC Controller AAT4900 CLK GND LX + VOUT = 0 to VIN IOUT = 0 to 1A
GND
-
Figure 1: AAT4900 DC-DC Converter Power Stage
6
4900.2004.04.1.0
Buffered Power Half-Bridge
Synchronous Buck DC-DC Converter Application
The losses associated with the AAT4900 high side switching MOSFET are due to switching losses and conduction losses. The conduction losses are associated with the Rds on characteristics of the output switching device. At the full load condition, assuming continuous conduction mode (CCM), the on losses can be derived from the following equations. D= D is the duty cycle I = Vo L*F V 1- o Vin Vo Vin
Output Current (A)
AAT4900
Tjmax = Ploss * jc = Tamb Using the above equations the graph below shows the current capability for some typical applications with a maximum junction temperatures of 150C and 120C. The increase in Rds(on) vs. temperature is estimated at 3.75 m for a 10C increase in junction temperature.
Step-Down Converter Limits F=1MHz
1.75 1.5 1.25
VIN=4.2V, VO=2.5V VIN=5.0V, VO=3.3V TJMAX=150C TJMAX=120C
1 0.75 0.5
I is the peak to peak inductor ripple current. High side switch RMS current Irms(HS) = 2 I2 I+ o 12
*
VIN=4.2V, VO=2.5V VIN=5.0V, VO=3.3V
D
25
35
45
55
65
75
85
Ambient Temperature (C)
Low side switch RMS current The low side RMS current is estimated by the following equation. Irms(LS) = Total Losses A simplified form of the above results (where the above descriptions of Irms has been approximated with Io) is given by: Ploss = Io2 * (Rdson(hs) * Vo +Rdson(ls) * (Vin -Vo) + (tsw * F * Io +Iq) * Vin Vin 2 I2 I+ o 12
*
(1 - D)
Substitution of the Irms equations with Io results in very little error when the inductor ripple current is 20% to 40% of the full load current. The equation also includes switching and quiescent current losses where tsw is approximated at 18 nsec and Iq is the no load quiescent current of the AAT4900. Quiescent current losses are associated with the gate drive of the output stage and biasing. Since the gate drive current varies with frequency and voltage, the bias current must be checked at the frequency, voltage, and temperature of operation with no load attached to the LX node. Once the above losses have been determined the maximum junction temperature can be calculated.
4900.2004.04.1.0
7
Buffered Power Half-Bridge
Gate Drive
When used as a MOSFET gate driver the break before make shoot-thru protection significantly reduces losses associated with the driver at high frequencies. The low Rdson of the output stage allows for a high peak gate current and fast switching speeds. A small package size facilitates close placement to the power device for optimum switching performance. The logic level inputs (CLK and EN) are high impedance inputs.
AAT4900
+5V Load Circuit IN Enable EN AAT4900 Clock CLK GND Ground LX
Figure 2: AAT4900 Gate Drive Configuration
Gate Drive Current Ratings
An estimate of the maximum gate drive capability with no external series resistor can be derived from equation 1. Note that the quiescent current varies with the ambient temperature, frequency of operation, and input voltage. The graphs below display the quiescent current and maximum gate charge drive capability at 85C ambient vs. frequency for various input voltages. The quiescent current was first measured over temperature for various input voltages with no load
attached. Equation 1 was then used to derive the maximum gate charge capability for the desired maximum junction temperature. Qg is the gate charge required to raise the gate of the load MOSFET to the input voltage. This value is taken from the MOSFET manufacturer's gate charge curve. Qg max = = 1 1MHz
*
1 Fsw
*
Tj max - Tamb -I ja * Vin max q
120C - 85C - 3.2mA = 40nC 190C/W * 4.2V
8
4900.2004.04.1.0
Buffered Power Half-Bridge
Maximum Gate Charge Load @ 85C Ambient Tjmax=120C
1000
AAT4900
No Load Operating Current at 85C Ambient
100
Operating Current (mA)
10
Gate Charge (nC)
VIN=5.5V VIN=5.0V VIN=4.2V VIN=2.7V
100
VIN=2.7V
10
1
VIN=4.2V VIN=5.0V VIN=5.5V
1000 10000
1 0.1 100 1000 10000 100
Frequency (kHz)
Frequency (kHz)
The AAT4900 is also ideally suited to be used as an efficient output driver for DC Brushless Motor Control. The inductive load switching capability of the AAT4900 eliminates the need for external diodes.
Enable +5V IN EN AAT4900 Clock CLK GND Ground LX DC Brushless Motor LX IN EN AAT4900 CLK GND
Figure 3: Typical Motor Control Block Diagram
4900.2004.04.1.0
9
Buffered Power Half-Bridge
Recommended Decoupling Layout Pattern
Because of the extremely fast switching speed and the high switching currents, optimum placement of the input capacitor is critical. It is recommended that a 0.1 - 10F 0805 or 1206 ceramic capacitor be placed as close as possible to the IC as shown in the diagram below. This helps to decouple the switching transients from the stray inductance present in the PCBoard.
AAT4900
AAT4900 4 CLK 3 EN
2 GND
5 V+
1 LX
CAP
10
4900.2004.04.1.0
Buffered Power Half-Bridge
AAT4900
CLK
LX
Figure 5: Timing Diagram
CLK
50%
50% tPHL
tPLH
tf
90% LX 10%
Figure 6: Switching Time Waveforms
VIN
IN EN LX CLK GND
10F
1000pF
Figure 7: Propagation Delay Test Circuit
4900.2004.04.1.0
11
Buffered Power Half-Bridge Ordering Information
Package SOT23-5 SC70JW-8 Marking ABXYY ABXYY Part Number (Tape and Reel) AAT4900IGV-T1 AAT4900IJS-T1
AAT4900
Note: Sample stock is generally held on all part numbers listed in BOLD. Note 1: XYY = assembly and date code.
Package Information
SOT23-5
2.85 0.15 1.90 BSC 0.95 BSC
1.575 0.125
1.10 0.20
0.60 REF
2.80 0.20
1.20 0.25
0.15 0.07 4 4
GAUGE PLANE
10 5
0.40 0.10
0.075 0.075
0.60 REF
0.45 0.15
0.10 BSC
Alldimensions in millimeters.
12
4900.2004.04.1.0
Buffered Power Half-Bridge
SC70JW-8
0.50 BSC 0.50 BSC 0.50 BSC
AAT4900
1.75 0.10 0.225 0.075 2.00 0.20
2.20 0.20
0.048REF 0.15 0.05
0.85 0.15
1.10 MAX
0.100
7 3
0.45 0.10 2.10 0.30
4 4
Alldimensions in millimeters.
0.05 0.05
4900.2004.04.1.0
13
Buffered Power Half-Bridge
AAT4900
AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech's standard warranty. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed.
Advanced Analogic Technologies, Inc.
830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737-4600 Fax (408) 737-4611 14
4900.2004.04.1.0

▲Up To Search▲

Price & Availability of AAT4900

	To Download AAT4900 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .