AAT4250 ANALOGICTECH | Alldatasheet

Document overview

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Technical content

Features

  • 1.8V to 5.5V Input voltage range
  • 120m Ω (5V) typical R DS(ON)
  • Low quiescent current
  • Typical 2µA
  • Typical 0.1µAwith Enable off
  • Only 2.0V needed for ON/OFF Control
  • Temperature range -40º to 85°C
  • 5kV ESDrating
  • 5-pin SOT23 or SC70JW-8 package

Applications

  • Hot swap supplies
  • Notebook computers
  • Personal communication devices AAT4250 Slew Rate Controlled Load Switch Typical Application AAT4250 SOT23 ON/OFF IN OUT GND ON 1µF0 . 1 µF INPUT GND GND CIN COUT OUTPUT Preliminary Information 4250.2001.12.0.94 1

(Top View) SC70JW-8 (Top View) GND GND GND 1 2 IN IN ON/OFF GND OUT 1 3 NC OUT GND IN ON/OFF Pin # SOT23-5 SC70JW Symbol Function 1 1 OUT P-channel MOSFETdrain 2 2, 3, 4, 5 GND Ground connection 3 n/a NC Not internally connected 4 6 ON/OFF Active-High Enable Input (Logic high turns the switch on) 5 7, 8 IN P-channel MOSFETsource AAT4250 Slew Rate Controlled Load Switch 2 4250.2001.12.0.94

Absolute Maximum Ratings (TA=25°C unless otherwise noted) Note: Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at con- ditions 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 100pF capacitor discharged through a 1.5kΩ resistor into each pin. Thermal Characteristics Note 2: Mounted on an AAT4250 demo board in still 25ºC air. Electrical Characteristics (VIN = 5V, TA = -40 to 85°C unless otherwise noted. Typical values are at TA=25°C) Note 3: For VIN outside this range consult typical ON/OFF threshold curve. Symbol Description Conditions Min Typ Max Units VIN Operation Voltage 1.8 5.5 V IQ Quiescent Current V IN = 5V, ON/OFF = VIN, IOUT = 0 2 4 µA IQ(OFF) Off Supply Current ON/OFF = GND, V IN = 5V, OUTopen 1 µA ISD(OFF) Off Switch Current ON/OFF = GND, V IN = 5V, VOUT = 0 0.1 1 µA VUVLO Undervoltage Lockout V IN falling 1.5 V VUVLO(hys) Undervoltage Lockout hysteresis 250 mV VIN = 5V 120 175 m Ω RDS(ON) On-Resistance V IN = 3V 135 200 m Ω VIN =1.8V 165 m Ω TCRDS On-Resistance Temp-Co 2800 ppm/ºC VIL ON/OFF Input Logic Low Voltage V IN = 2.7V to 5.5V3 0.8 V ISINK ON Input leakage V ON = 5V 0.01 1 µA TD Output Turn-On Delay Time 300 µs TOFF Turn-Off Fall Time V IN=5V, RLOAD=10Ω 10 µs TOFF Turn-Off Fall Time V IN=3V, RLOAD=5Ω 10 µs TON Turn-On Rise Time V IN=5V, RLOAD=16.5Ω , TA=0 to 50º C 1000 µ s TON Turn-On Rise Time V IN=5V, RLOAD=10Ω , COUT=0.1µF 1500 µs TON Turn-On Rise Time V IN=3V, RLOAD=5Ω , COUT=0.1µF 1500 µs Symbol Description Value Units ΘJA Thermal Resistance (SOT23-5 or SC70JW-8)2 150 °C/W PD Power Dissipation (SOT23-5 or SC70JW-8)2 667 mW Symbol Description Value Units VIN IN to GND -0.3 to 6 V VON ON/OFF to GND -0.3 to 6 V VOUT OUTto GND -0.3 to V IN+0.3 V IMAX Maximum Continuous Switch Current 1.7 A IDM Maximum Pulsed Current IN ≥ 2.5V 4 A IN < 2.5V 2 A TJ Operating Junction Temperature Range -40 to 150 °C TLEAD Maximum Soldering Temperature (at Leads) 300 °C VESD ESDRating1 - HBM 5000 V AAT4250 Slew Rate Controlled Load Switch 4250.2001.12.0.94 3

(Unless otherwise noted, VIN = 5V, TA = 25°C) Turn-On Time vs. Temperature 0.5 1.0 1.5 2.0 2.5 3.0 -40 -20 0 20 40 60 80 100 Temperature (°C) Turn-ON Time (ms) CIN=1µF, COUT=0.1µF VIN=5V RLOAD=10ΩVIN=3V RLOAD=5Ω Turn-OFF Time vs. Temperature -40 -20 0 20 40 60 80 100 Temperature (°C) CIN=1µF, COUT=0.1µF Turn-OFF Time (µs) VIN=5V RLOAD=10Ω VIN=3V RLOAD=5Ω Off-Switch Current vs. Temperature 100 1000 10000 -40 -20 0 20 40 60 80 100 Temperature (°C) Off-Switch Current (nA) Off-Supply Current vs. Temperature 100 1000 -40 -20 0 20 40 60 80 100 Temperature (°C) Off-Supply Current (nA) Quiescent Current vs. VIN 0.5 1.5 2.5 3.5 0123456 Quiescent Current (µA) VIN Quiescent Current vs. Temperature 0.5 1.5 2.5 3.5 -40 -20 0 20 40 60 80 100 Temperature (°C) Quiescent Current (µA) VIN=3V VIN=5V AAT4250 Slew Rate Controlled Load Switch 4 4250.2001.12.0.94

(Unless otherwise noted, VIN = 5V, TA = 25°C) CIN=1µF,COUT=1µF,VIN=5V Turn Off Waveforms Time(µs) -1 1 3 5 7 9 11 13 15 V(out) Volt V(ON/OFF)0 CIN=1µF,COUT=1µF,VIN=3V Turn Off Waveforms Time (µs) -1 1 3 5 7 9 11 13 15 V(out) Volt V(ON/OFF) -1 0 1 2 3 4 1.2 Time(ms) CIN=1µF,COUT=10µF,VIN=5V Turn On Waveforms V(out) 0.8 0.6 0.4 0.2 I(in) Volt A V(ON/OFF) Volt -1 0 1 2 3 4 0.5 1.5 Time(ms) CIN=1µF,COUT=10µF,VIN=3V Turn On Waveforms V(out) I(in) A V(ON/OFF) Volt -1 0 1 2 3 4 1.2 Time(ms) CIN=1µF,COUT=0.1µF,VIN=5V Turn On Waveforms V(out) 0.8 0.6 0.4 0.2 I(in) A V(ON/OFF) Volt -1 0 1 2 3 4 0.5 1.5 Time (ms) CIN=1µF,COUT=0.1µF,VIN=3V Turn On Waveforms V(ON/OFF) V(out) I(in) A AAT4250 Slew Rate Controlled Load Switch 4250.2001.12.0.94 5

(Unless otherwise noted, VIN = 5V, TA = 25°C) Typical ON/OFF Threshold vs. VIN 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 VIN ON/OFF Threshold VIH VIL RDS(ON) vs.VIN 110 120 130 140 150 160 170 180 190 VIN RDS(ON)(mΩ) IOUT = 100mA RDS(ON) vs. Temperature 120 160 -40 -20 0 20 40 60 80 100 Temperature (°C) RDS(ON) (mΩ) VIN=3V VIN=5V AAT4250 Slew Rate Controlled Load Switch 6 4250.2001.12.0.94

The AAT4250 is a slew rate controlled P-channel MOSFETpower switch designed for high-side load- switching applications. It operates with input volt- ages ranging from 1.8V to 5.5V which, along with its extremely low operating current, makes it ideal for battery-powered applications. In cases where the input voltage drops below 1.8V, the AAT4250 MOS- FETis protected from entering the saturated region of operation by automatically shutting down. In addition, the TTL compatible ON/OFF pin makes the AAT4250 an ideal level shifted load-switch. The slew rate controlling feature eliminates in-rush cur- rent when the MOSFET is turned on, allowing the AAT4250 to be implemented with a small input capacitor, or no input capacitor at all. During slew- ing, the current ramps linearly until it reaches the level required for the output load condition. The proprietary control method works by careful control and monitoring of the MOSFETgate voltage. When the device is switched ON, the gate voltage is quick- ly increased to the threshold level of the MOSFET. Once at this level, the current begins to slew as the gate voltage is slowly increased until the MOSFET becomes fully enhanced. Once it has reached this point, the gate is quickly increased to the full input voltage and R DS(ON) is minimized. AAT4250 Slew Rate Controlled Load Switch 4250.2001.12.0.94 7 Functional Block Diagram Under- voltage Lockout Level Shift Slew Rate Control IN ON/OFF GND OUT

Typically a 1µF or larger capacitor is recommend- ed for CIN in most applications. AC IN capacitor is not required for basic operation, however, it is use- ful in preventing load transients from affecting up stream circuits. C IN should be located as close to the device VIN pin as practically possible. Ceramic, tantalum or aluminum electrolytic capacitors may be selected for C IN. There is no specific capacitor ESR requirement for CIN. However, for higher cur- rent operation, ceramic capacitors are recom- mended for C IN due to their inherent capability over tantalum capacitors to withstand input current surges from low impedance sources such as bat- teries in portable devices. Output Capacitor For proper slew operation, a 0.1µF capacitor or greater between VOUTand GND is required. Likewise, with the output capacitor, there is no spe- cific capacitor ESR requirement. If desired, C OUT maybe increased without limit to accommodate any load transient condition without adversely affecting the slew rate. Enable Function The AAT4250 features an enable / disable function. This pin (ON) is active high and is compatible with TTLor CMOS logic. To assure the load switch will turn on, the ON control level must be greater than 2.0 volts. The load switch will go into shutdown mode when the voltage on the ON pin falls below 0.8 volts. When the load switch is in shutdown mode, the OUTpin is tristated, and quiescent cur- rent drops to leakage levels below 1µA. Reverse Output to Input Voltage Conditions and Protection Under normal operating conditions a parasitic diode exists between the output and input of the load switch. The input voltage should always remain greater than the output load voltage main- taining a reverse bias on the internal parasitic diode. Conditions where V OUT might exceed VIN should be avoided since this would forward bias the internal parasitic diode and allow excessive current flow into the V OUT pin and possibly damage the load switch. In applications where there is a possibility of V OUT exceeding VIN for brief periods of time during nor- mal operation, the use of a larger value CIN capaci- tor is highly recommended. A larger value of C IN with respect to COUT will effect a slower CIN decay rate during shutdown, thus preventing V OUT from exceeding VIN. In applications where there is a greater danger of VOUT exceeding VIN for extended periods of time, it is recommended to place a schot- tky diode from V IN to VOUT (connecting the cathode to VIN and anode to VOUT). The Schottky diode for- ward voltage should be less then 0.45 volts. Thermal Considerations and High Output Current Applications The AAT4250 is designed to deliver a continuous output load current. The limiting characteristic for maximum safe operating output load current is package power dissipation. In order to obtain high operating currents, careful device layout and circuit operating conditions need to be taken into account. The following discussions will assume the load switch is mounted on a printed circuit board utiliz- ing the minimum recommended footprint as stated in the layout considerations section. At any given ambient temperature (T A) the maxi- mum package power dissipation can be deter- mined by the following equation: P D(MAX) = [TJ(MAX) - TA] / ΘJA Constants for the AAT4250 are maximum junction temperature, TJ(MAX) = 125°C, and package thermal resistance, ΘJA = 150°C/W. Worst case conditions are calculated at the maximum operating tempera- ture where T A = 85°C. Typical conditions are cal- culated under normal ambient conditions where TA = 25°C. At TA = 85°C, PD(MAX) = 267mW. At TA = 25°C, PD(MAX) = 667mW. The maximum continuous output current for the AAT4250 is a function of the package power dissi- pation and the R DS of the MOSFETat TJ(MAX). The maximum RDS of the MOSFET at TJ(MAX) is calcu- lated by increasing the maximum room tempera- ture R DS by the RDS temperature coefficient. The temperature coefficient (TC) is 2800ppm/°C. Therefore, at 125°C R DS(MAX) = RDS(25°C) × (1 + TC × ∆ T) RDS(MAX) = 224mΩ AAT4250 Slew Rate Controlled Load Switch 8 4250.2001.12.0.94

For maximum current, refer to the following equation: IOUT(MAX) < ( PD(MAX) / RDS)1/2 For example, if VIN = 5V, RDS(MAX)=224mΩ and TA = 25°C, IOUT(MAX) = 1.7A. If the output load current were to exceed 1.7Aor if the ambient temperature were to increase, the internal die temperature will increase, and the device will be damaged. Higher peak currents can be obtained with the AAT4250. To accomplish this, the device thermal resistance must be reduced by increasing the heat sink area or by operating the load switch in a duty cycle manner. Duty cycles with peaks less than 2ms in duration can be considered using the method below. High Peak Output Current Applications Some applications require the load switch to oper- ate at a continuous nominal current level with short duration high current peaks. Refer to the I DM spec- ification in the Absolute Maximum table to ensure the AAT 4250’s maximum pulsed current rating is not exceeded. The duty cycle for both output cur- rent levels must be taken into account. To do so, first calculate the power dissipation at the nominal continuous current level, and then add in the addi- tional power dissipation due to the short duration high current peak scaled by the duty factor. For example, a 4V system using an AAT4250 oper- ates at a continuous 100mAload current level and has short 2Acurrent peaks, as in a GSM applica- tion. The current peak occurs for 576µs out of a 4.61ms period. First, the current duty cycle is calculated: % Peak Duty Cycle: X/100 = 576µs/4.61ms % Peak Duty Cycle = 12.5% The load current is 100mAfor 87.5% of the 4.61ms period and 2A for 12.5% of the period. Since the Electrical Characteristics do not report R DS MAXfor 4 volts operation, it must be calculated approximated by consulting the chart of RDSON vs. VIN. The Rds reported for 5 volt R DS can be scaled by the ratio seen in the chart to derive the Rds for 4 volt V IN: 175mΩ x 120mΩ/115mΩ = 183mΩ. Derated for temperature: 183mΩ x (1 + .002800 x (125°C - 25°C)) = 235m Ω . The power dissipation for a 100mAload is calculated as follows: PD(MAX) = I2 OUT x RDS PD(100mA) = (100mA)2 x 235mΩ PD(100mA) = 2.35mW PD(87.5%D/C) = %DC x PD(100mA) PD(87.5%D/C) = 2.1mW The power dissipation for 100mA load at 87.5% duty cycle is 2.1mW. Now the power dissipation for the remaining 12.5% of the duty cycle at 2Ais cal- culated: P D(MAX) = I2 OUT x RDS PD(2A) = (2A)2 x 235mΩ PD(2A) = 940mW PD(12.5%D/C) = %DC x PD(2A) PD(12.5%D/C) = 0.125 x 940mW PD(12.5%D/C) = 117.5mW The power dissipation for 2A load at 12.5% duty cycle is 117mW. Finally, the two power figures are summed to determine the total true power dissipa- tion under the varied load. P D(total) = PD(100mA) + PD(2A) PD(total) = 2.1mW + 117.5mW PD(total) = 120mW The maximum power dissipation for the AAT4250 operating at an ambient temperature of 85°C is 267mW. The device in this example will have a total power dissipation of 120mW. This is well with in the thermal limits for safe operation of the device, in fact, at 85°C, the AAT4250 will handle a 2Apulse for up to 28% duty cycle. At lower ambi- ent temperatures the duty cycle can be further increased. AAT4250 Slew Rate Controlled Load Switch 4250.2001.12.0.94 9

Slew Rate Controlled Load Switch 10 4250.2001.12.0.94 Figure 1: Evaluation board Figure 2: Evaluation board Figure 3: Evaluation board top side silk screen layout / component side layout solder side layout assembly drawing Printed Circuit Board Layout Recommendations For proper thermal management, and to take advantage of the low RDSON of the AAT4250, a few circuit board layout rules should be followed: Vin and Vout should be routed using wider than normal traces, and GND should be connected to a ground plane. For best performance, C IN and COUT should be placed close to the package pins. Evaluation Board Layout The AAT4250 evaluation layout follows the printed circuit board layout recommendations, and can be used for good applications layout. Note: Board layout shown is not to scale.

Slew Rate Controlled Load Switch 4250.2001.12.0.94 11

Ordering Information

Package Information

E A c b D e L Θ H S Package Marking Part Number Bulk Tape and Reel SOT23-5 N/A AAT4250IGV-T1 SC70JW-8 N/A AAT4250IJS-T1 Dim Millimeters Inches Min Max Min Max A 1.00 1.30 0.039 0.051 A1 0.00 0.10 0.000 0.004 A2 0.70 0.90 0.028 0.035 b 0.35 0.50 0.014 0.020 c 0.10 0.25 0.004 0.010 D 2.70 3.10 0.106 0.122 E1.40 1.80 0.055 0.071 e 1.90 0.075 H 2.60 3.00 0.102 0.118 L 0.37 0.015 S 0.45 0.55 0.018 0.022 S1 0.85 1.05 0.033 0.041 Θ 1° 9° 1° 9°

D AA2 b E eee L Θ c 0.048REF AAT4250 Slew Rate Controlled Load Switch 12 4250.2001.12.0.94 Advanced Analogic Technologies, Inc.

1250 Oakmead Parkway, Suite 310, Sunnyvale, CA94086

Phone (408) 524-9684 Fax (408) 524-9689 Dim Millimeters Inches Min Max Min Max E2.10 BSC 0.083 BSC E1 1.75 2.00 0.069 0.079 L 0.23 0.40 0.009 0.016 A 1.10 0.043 A1 0 0.10 0.004 A2 0.70 1.00 0.028 0.039 D 2.00 BSC 0.079 BSC e 0.50 BSC 0.020 BSC b 0.15 0.30 0.006 0.012 c 0.10 0.20 0.004 0.008 Θ 08 º08 º Θ1 4º 10º 4º 10º