HT7718S Datasheet, PDF (1/29 Pages) Holtek Semiconductor Inc – 100mA PFM Synchronous Step-up DC/DC Converter

HT77xxS
100mA PFM Synchronous
Step-up DC/DC Converter
Features
• Low start-up voltage: 0.7V (Typ.)
• High efficiency: 1.8V ≤ V_OUT ≤ 2.2V upper 80%,
2.7V ≤ V_OUT ≤ 5.0V upper 85% (Typ.)
• High output voltage accuracy: ±2.5%
• Output voltage: 1.8V, 2.2V, 2.7V, 3.0V, 3.3V, 3.7V,
5.0V
• Output current up to 100mA
• Ultra low supply current I_DD: 4μA (Typ.)
• Low ripple and low noise
• Low shutdown current: 0.1μA (Typ.)
• TO92, SOT89, SOT23 and SOT23-5 package
Applications
• Palmtops/PDAs
• Portable communicators/Smartphones
• Cameras/Camcorders
• Battery-powered equipment
General Description
The HT77xxS devices are a high efficiency PFM syn-
chronous step-up DC-DC converter series which are
designed to operate with both wire wound chip power
inductors and also with multi-layered chip power
inductors. The device series have the advantages of
extremely low start-up voltage as well as high output
voltage accuracy. Being manufactured using CMOS
technology ensures ultra low supply current. Because
of their higher operating frequency, up to 500 kHz,
the devices have the benefits of requiring smaller out-
line type lower value external inductors and capaci-
tors. The higher operating frequency also offers the
advantages of much reduced audio frequency noise.
The devices require only three external components
to provide a fixed output voltage of 1.8V, 2.2V, 2.7V,
3.0V, 3.3V, 3.7V or 5.0V.
The HT77xxS devices include an internal oscillator,
PFM control circuit, driver transistor, reference volt-
age unit and a high speed comparator. They employ
pulse frequency modulation techniques, to obtain
minimum supply current and ripple at light output
loading. These devices are available in space saving
TO92, SOT89, SOT23 and SOT23-5 packages. For
SOT23-5 package types, they also include an internal
chip enable function to reduce power consumption
when in the shutdown mode.
Selection Table
Part No.
HT7718S
HT7722S
HT7727S
HT7730S
HT7733S
HT7737S
HT7750S
Output Voltage
1.8V
2.2V
2.7V
3.0V
3.3V
3.7V
5.0V
Tolerance
±2.5%
Package
TO92
SOT89
SOT23
SOT23-5
Rev. 1.00
1
February 22, 2012