LM2608

Features:

Sub-miniature 10-pin thin Micro SMD package
Only four tiny surface-mount external components required
Uses small ceramic capacitors
Internal soft start
Current and Thermal shutdown protection
No external compensation required




Application

Mobile Phones
Hand-Held Radios
Battery Powered Devices




Pinout






Specifications

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.

PVIN, VDD, to SGND −0.2V to +6V
PGND to SGND −0.2V to +0.2V
EN, SYNC/MODE, VSEL to SGND−0.2V to +6V
FB, SW (GND −0.2V) to
(V_DD +0.2V)
Storage Temperature Range −45°C to +150°C
Lead temperature
(Soldering, 10 sec.) 260°C
Junction Temperature (Note 2) −25°C to 125°C
Minimum ESD Rating
Human body model, C = 100pF, R =
1.5 k±2.0kV
Thermal Resistance (JA)
LM2608ATL(Note 3) 140°C/W

Output Current	400 mA
Input Min Voltage	2.8 Volt
Input Max Voltage	5.5 Volt
Output Min	1.8 Volt
Output Max	1.8 Volt
Frequency Min	500 kHz
Frequency Max	1000 kHz
Efficiency (peak)	91 %
On/Off Pin	Yes
Error Flag	No
SoftStart	Yes
Sync Pin	Yes
Inverting	No
Flyback	No
RegType	Switching Regulator
Temperature Min	-30 deg C
Temperature Max	85 deg C
Adjustable Output	No
Adj Switch Frequency	Yes
PWM Mode	Current
Topology	Synchronous Buck
Special Features	Pin-selectable PWM/PFM modes, Max Iq in shutdown is 3uA, 2% output accuracy, Linear micropower operation mode, Pin-selectable output voltage
Step-Down	Yes
Multiple Output Capability	Yes
Output Power	Undefined Watt
Output Voltage	1.8 Volt
Output Range	1.8V or 1.5V
Switching Frequency	600 kHz
Feedback Voltage	Undefined Volt
Regulator Family	Undefined
Synchronous Rectification	Yes
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Description

The LM2608 step-down DC-DC converter is optimized for powering ultra-low voltage circuits from a single Lithium-Ion cell. It provides up to 400mA over an input voltage range of 2.8V to 5.5V. Operating from a 1.35V reference, this device provides pin-selectable output voltages of 1.3V/1.5V (300mA) for low voltage version or 1.5V/1.8V (400mA) for high voltage version. This allows adjustment for DSP or CPU voltage options, as well as dynamic output voltage switching for reduced power consumption. Internal synchronous rectification provides high efficiency.

The LM2608 offers superior features and performance for mobile phones and similar portable applications with complex power management systems. Pin-selectable PWM lownoise and linear micropower modes offer improved system control for maximizing battery life. During full power operation, fixed-frequency PWM mode reduces interference in RF and data acquisition applications by minimizing noise harmonics at sensitive IF and sampling frequencies. A SYNC input allows synchronizing the switching frequency in a range of 500kHz to 1MHz to avoid noise from intermodulation with system frequencies. Linear operation reduces quiescent current to 20A (typ) during system standby for extended battery life. It provides up to 3 mA in the linear mode. Shutdown reduces battery consumption to 0.02A (typ.).

The LM2608 is available in a 10 pin Micro SMD package. This package uses National's wafer level chip-scale Micro SMD technology and offers the smallest possible size. A high switching frequency (600KHz) allows use of tiny surfacemount components. Only four small external surface-mount components, an inductor and three ceramic capacitors are required. Pin selectable output voltage eliminates the need for bulky external feedback resistors.