5V, 500mA, 2.2 MHz Step-Down Regulator with Low
Quiescent Current
IFX90121
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Overview
500 mA step down voltage regulator
5 V Output voltage
± 2% output voltage tolerance
Low quiescent current (less than 45µA at nominal input voltage)
Integrated power transistor
Current mode PWM regulation
PFM mode for light load current
Input voltage range from 4.75V to 45V
2.2 MHz switching frequency
100% Duty cycle
Synchronization input
Very low shutdown current consumption (<2 µA)
Soft-start function
Input undervoltage lockout
Suited for industrial applications:
T
j
= -40 °C to +125 °C
Green Product (RoHS compliant)
PG-SSOP-14
Description
The IFX90121 is a high frequency PWM step-down DC/DC converter with an integrated PMOS power switch,
packaged in a small PG-SSOP-14 with exposed pad. The wide input voltage range from 4.75 to 45 V makes the
IFX90121 suitable for a wide variety of applications.
The switching frequency of nominal 2.2 MHz allows the use of small and cost-effective inductors and capacitors,
resulting in a low, predictable output voltage ripple and in minimized consumption of board space.
In light load condition the device operates in Pulse Frequency Modulation (PFM) to optimize the efficiency.
Between the single pulses, all internal controlling circuitry is switched off to reduce the internal power consumption.
The IFX90121 includes protection features such as a cycle-by-cycle current limitation, over-temperature shutdown
and input under voltage lockout. The enable function, in shutdown mode with less than 2 µA current consumption,
enables easy power management in battery-powered systems.
The voltage regulation loop provides an excellent line and load regulation, the stability of the loop is ensured by
an internal compensation network. This compensation network combined with a current mode regulation control
guarantees a highly effective line transient rejection. During start-up the integrated soft-start limits the inrush
current peak and prevents an output voltage overshoot.
Type
IFX90121ELV50
Package
PG-SSOP-14
Marking
90121E50
Data Sheet
2
Rev. 1.0, 2013-07-02
IFX90121
Pin Configuration
3
3.1
Pin Configuration
Pin Assignment
IFX90121
N.C.
N.C.
N.C.
SYNC
FREQ
N.C.
FB
1
2
3
4
5
6
7
14
13
12
11
10
9
8
EN
VS
N.C.
SWO
GND
GND
N.C.
PG-SSOP14
Figure 2
Pin Configuration
3.2
Pin
1
2
3
4
Pin Definitions and Functions
Symbol Function
N.C.
N.C.
N.C.
SYNC
Not Connected.
Internally not connected. Leave open or connect to GND.
Not Connected.
Internally not connected. Leave open or connect to GND.
Not Connected.
Internally not connected. Leave open or connect to GND.
Synchronization Input
Connect to an external clock signal in order to synchronize/adjust the switching frequency. This
feature is not functionally in PFM mode.
Frequency Adjustment Pin
Connect an external resistor to GND to adjust the switching frequency, do not leave open. In
case the synchronization option is used, the resistor must be dimensioned close to the desired
synchronization frequency.
Not Connected.
Internally not connected. Leave open or connect to GND.
Feedback Input
Connect this pin directly to the output capacitor. Also input for internal power supply. The internal
power supply is taken from the output voltage.
Not Connected.
Internally not connected. Leave open or connect to GND.
Ground
Connect this pin directly with low inductive and broad trace to ground, do not leave open.
Ground
Connect this pin directly with low inductive and broad trace to ground, do not leave open.
5
Rev. 1.0, 2013-07-02
5
FREQ
6
7
N.C.
FB
8
9
10
N.C.
GND
GND
Data Sheet
单片机
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