Datasheet LT3641 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | Dual Monolithic Buck Regulator with Power-On Reset and Watchdog Timer |
| Pages / Page | 28 / 1 — FEATURES. DESCRIPTION. High Voltage Buck Regulator:. 4V to 42V Operating … |
| File Format / Size | PDF / 452 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. High Voltage Buck Regulator:. 4V to 42V Operating Range. 1.3A. Output. Current
Model Line for this Datasheet
Text Version of Document
LT3641 Dual Monolithic Buck Regulator with Power-On Reset and Watchdog Timer
FEATURES DESCRIPTION
n
High Voltage Buck Regulator:
The LT®3641 is a dual channel, current mode monolithic buck
4V to 42V Operating Range
switching regulator with a power-on reset and a watchdog
1.3A Output Current
timer. Both regulators are synchronized to a single oscillator n
Input Transient Protection to 55V
with an adjustable frequency (350kHz to 2.5MHz). At light n
Low Voltage Synchronous Buck Regulator:
loads, both regulators operate in low ripple Burst Mode®
2.5V to 5.5V Input Voltage Range
to maintain high effi ciency and low output ripple.
1.1A Output Current
The high voltage channel is a nonsynchronous buck with n
Synchronizable, Adjustable 350kHz to 2.5MHz
an internal 2.4A top switch that operates from an input
Switching Frequency
of 4V to 42V and input transient protection to 55V. The n
Programmable Power-On Reset Timer
low voltage channel operates from an input of 2.5V to n
Programmable Window Mode Watchdog Timer
5.5V. Internal synchronous power switches provide high n Typical Quiescent Current: 290μA effi ciency without the need of external Schottky diode. n Short-Circuit Robust Both channels have cycle-by-cycle current limit, providing n Programmable Soft-Start protection against shorted outputs. n Low Shutdown Current: IQ < 1μA n Thermal Shutdown The power-on reset and watchdog timeout periods are n Available in Thermally Enhanced 28-Lead both adjustable using external capacitors. The window (4mm × 5mm) QFN and 28-Lead TSSOP Packages mode watchdog timer fl ags when the μP pulses group too close together or too far apart.
APPLICATIONS
The LT3641 is available in a 28-pin 4mm × 5mm QFN n Industrial Power Supplies package and 28-pin TSSOP package. Both packages have n Automotive Electronic Control Units an exposed pad for low thermal resistance. L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION 2MHz 5V/0.8A and 3.3V/0.5A Step Down Regulators
0.22μF
HV Channel Effi ciency, LV Channel Effi ciency,
VIN
2MHz, V 2MHz, V
7V TO 42V*
OUT1 = 5V OUT2 = 3.3V
10μF 4.7μH VOUT1 EN/UVLO V SW BST SW1 IN 90 95 5V/0.8A SYNC 301k WDE DA 22μF VIN = 12V PGOOD2 FB1 90 VIN2 = 5V 85 VOUT1 100k 100k 100k 85 RST1 LT3641 VIN2 80 RST2 EN2 μP WDO 2.2μH 80 VOUT2 EFFICIENCY (%) EFFICIENCY (%) WDI SW2 3.3V/0.5A 226k 75 22μF 75 CWDT FB2 CPOR RT GND SS2 SS1 49.9k 1.5nF 1.5nF 1nF 70 70 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 0 0.2 0.4 0.6 0.8 1.0 1.2 32.4k 1nF VOUT1 CURRENT (A) VOUT2 CURRENT (A) 3641 TA01a 3641 TA01b 3641 TA01c * FOR INPUT VOLTAGES ABOVE 42V RESTRICTIONS APPLY 3641fa 1
FEATURES DESCRIPTION
n
High Voltage Buck Regulator:
The LT®3641 is a dual channel, current mode monolithic buck
4V to 42V Operating Range
switching regulator with a power-on reset and a watchdog
1.3A Output Current
timer. Both regulators are synchronized to a single oscillator n
Input Transient Protection to 55V
with an adjustable frequency (350kHz to 2.5MHz). At light n
Low Voltage Synchronous Buck Regulator:
loads, both regulators operate in low ripple Burst Mode®
2.5V to 5.5V Input Voltage Range
to maintain high effi ciency and low output ripple.
1.1A Output Current
The high voltage channel is a nonsynchronous buck with n
Synchronizable, Adjustable 350kHz to 2.5MHz
an internal 2.4A top switch that operates from an input
Switching Frequency
of 4V to 42V and input transient protection to 55V. The n
Programmable Power-On Reset Timer
low voltage channel operates from an input of 2.5V to n
Programmable Window Mode Watchdog Timer
5.5V. Internal synchronous power switches provide high n Typical Quiescent Current: 290μA effi ciency without the need of external Schottky diode. n Short-Circuit Robust Both channels have cycle-by-cycle current limit, providing n Programmable Soft-Start protection against shorted outputs. n Low Shutdown Current: IQ < 1μA n Thermal Shutdown The power-on reset and watchdog timeout periods are n Available in Thermally Enhanced 28-Lead both adjustable using external capacitors. The window (4mm × 5mm) QFN and 28-Lead TSSOP Packages mode watchdog timer fl ags when the μP pulses group too close together or too far apart.
APPLICATIONS
The LT3641 is available in a 28-pin 4mm × 5mm QFN n Industrial Power Supplies package and 28-pin TSSOP package. Both packages have n Automotive Electronic Control Units an exposed pad for low thermal resistance. L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION 2MHz 5V/0.8A and 3.3V/0.5A Step Down Regulators
0.22μF
HV Channel Effi ciency, LV Channel Effi ciency,
VIN
2MHz, V 2MHz, V
7V TO 42V*
OUT1 = 5V OUT2 = 3.3V
10μF 4.7μH VOUT1 EN/UVLO V SW BST SW1 IN 90 95 5V/0.8A SYNC 301k WDE DA 22μF VIN = 12V PGOOD2 FB1 90 VIN2 = 5V 85 VOUT1 100k 100k 100k 85 RST1 LT3641 VIN2 80 RST2 EN2 μP WDO 2.2μH 80 VOUT2 EFFICIENCY (%) EFFICIENCY (%) WDI SW2 3.3V/0.5A 226k 75 22μF 75 CWDT FB2 CPOR RT GND SS2 SS1 49.9k 1.5nF 1.5nF 1nF 70 70 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 0 0.2 0.4 0.6 0.8 1.0 1.2 32.4k 1nF VOUT1 CURRENT (A) VOUT2 CURRENT (A) 3641 TA01a 3641 TA01b 3641 TA01c * FOR INPUT VOLTAGES ABOVE 42V RESTRICTIONS APPLY 3641fa 1
