Datasheet LT1765, LT1765-1.8, LT1765-2.5, LT1765-3.3, LT1765-5 (Analog Devices)
| Hersteller | Analog Devices |
| Beschreibung | Monolithic 3A, 1.25MHz Step-Down Switching Regulator |
| Seiten / Seite | 20 / 1 — FEATURES. DESCRIPTION. 3A Switch in a Thermally Enhanced 16-Lead. TSSOP … |
| Dateiformat / Größe | PDF / 216 Kb |
| Dokumentensprache | Englisch |
FEATURES. DESCRIPTION. 3A Switch in a Thermally Enhanced 16-Lead. TSSOP or 8-Lead SO Package
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LT1765/LT1765-1.8/LT1765-2.5/ LT1765-3.3/LT1765-5 Monolithic 3A, 1.25MHz Step-Down Switching Regulator
FEATURES DESCRIPTION
n
3A Switch in a Thermally Enhanced 16-Lead
The LT®1765 is a 1.25MHz monolithic buck switching
TSSOP or 8-Lead SO Package
regulator. A high effi ciency 3A, 0.09Ω switch is included n
Constant 1.25MHz Switching Frequency
on the die together with all the control circuitry required n
Wide Operating Voltage Range: 3V to 25V
to construct a high frequency, current mode switching n
High Effi ciency 0.09Ω Switch
regulator. Current mode control provides fast transient n 1.2V Feedback Reference Voltage response and excellent loop stability. n Uses Low Profi le Surface Mount Components New design techniques achieve high effi ciency at high n Low Shutdown Current: 15μA switching frequencies over a wide operating voltage n Synchronizable to 2MHz range. A low dropout internal regulator maintains con- n Current Mode Loop Control sistent performance over a wide range of inputs from n Constant Maximum Switch Current Rating at 24V systems to Li-Ion batteries. An operating supply All Duty Cycles* current of 1mA improves effi ciency, especially at lower n Available in 8-Lead SO and 16-Lead Thermally output currents. Shutdown reduces quiescent current to Enhanced TSSOP Packages 15μA. Maximum switch current remains constant at all duty cycles. Synchronization allows an external logic level
APPLICATIONS
signal to increase the internal oscillator into the range of 1.6MHz to 2MHz. n DSL Modems n Full cycle-by-cycle current control and thermal shutdown Portable Computers n are provided. High frequency operation allows the reduc- Regulated Wall Adapters n tion of input and output fi ltering components and permits Battery-Powered Systems n the use of chip inductors. Distributed Power L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. *Patent Pending
TYPICAL APPLICATION 5V to 3.3V Step-Down Converter Effi ciency vs Load Current
CMDSH-3 90 VIN = 10V VOUT = 5V 0.18μF 85 INPUT BOOST 1.5μH OUTPUT 5V VIN V 3.3V SW 2.5A 2.2μF LT1765-3.3 80 CERAMIC OFF ON SHDN FB SYNC GND VC EFFICIENCY (%) 4.7μF 2.2nF UPS120 CERAMIC 75 1765 TA01 70 0 0.5 1.0 1.5 2.0 SWITCH CURRENT (A) 1765 • TAO1a 1765fd 1
FEATURES DESCRIPTION
n
3A Switch in a Thermally Enhanced 16-Lead
The LT®1765 is a 1.25MHz monolithic buck switching
TSSOP or 8-Lead SO Package
regulator. A high effi ciency 3A, 0.09Ω switch is included n
Constant 1.25MHz Switching Frequency
on the die together with all the control circuitry required n
Wide Operating Voltage Range: 3V to 25V
to construct a high frequency, current mode switching n
High Effi ciency 0.09Ω Switch
regulator. Current mode control provides fast transient n 1.2V Feedback Reference Voltage response and excellent loop stability. n Uses Low Profi le Surface Mount Components New design techniques achieve high effi ciency at high n Low Shutdown Current: 15μA switching frequencies over a wide operating voltage n Synchronizable to 2MHz range. A low dropout internal regulator maintains con- n Current Mode Loop Control sistent performance over a wide range of inputs from n Constant Maximum Switch Current Rating at 24V systems to Li-Ion batteries. An operating supply All Duty Cycles* current of 1mA improves effi ciency, especially at lower n Available in 8-Lead SO and 16-Lead Thermally output currents. Shutdown reduces quiescent current to Enhanced TSSOP Packages 15μA. Maximum switch current remains constant at all duty cycles. Synchronization allows an external logic level
APPLICATIONS
signal to increase the internal oscillator into the range of 1.6MHz to 2MHz. n DSL Modems n Full cycle-by-cycle current control and thermal shutdown Portable Computers n are provided. High frequency operation allows the reduc- Regulated Wall Adapters n tion of input and output fi ltering components and permits Battery-Powered Systems n the use of chip inductors. Distributed Power L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. *Patent Pending
TYPICAL APPLICATION 5V to 3.3V Step-Down Converter Effi ciency vs Load Current
CMDSH-3 90 VIN = 10V VOUT = 5V 0.18μF 85 INPUT BOOST 1.5μH OUTPUT 5V VIN V 3.3V SW 2.5A 2.2μF LT1765-3.3 80 CERAMIC OFF ON SHDN FB SYNC GND VC EFFICIENCY (%) 4.7μF 2.2nF UPS120 CERAMIC 75 1765 TA01 70 0 0.5 1.0 1.5 2.0 SWITCH CURRENT (A) 1765 • TAO1a 1765fd 1