RT9193-2HGU5 Richtek USA Inc, RT9193-2HGU5 Datasheet - Page 8

• Manufacturer Part Number: RT9193-2HGU5
• Description: IC REG LDO 2.85V 300MA SC70-5
• Manufacturer: Richtek USA Inc

Specifications of RT9193-2HGU5

• Regulator Topology: Positive Fixed
• Voltage - Output: 2.85V
• Voltage - Input: Up to 5.5V
• Voltage - Dropout (typical): 0.22V @ 300mA
• Number Of Regulators: 1
• Current - Output: 300mA (Max)
• Current - Limit (min): 360mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 6-TSSOP (5 lead), SC-88A, SOT-353
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

RT9193
Applications Information
Like any low dropout regulator, the external capacitors
used with the RT9193 must be carefully selected for
regulator stability and performance. Using a capacitor
whose value is >1μF on the RT9193 input and the amount
of capacitance can be increased without limit. The input
capacitor must be located a distance of not more than 0.5
inch from the input pin of the IC and returned to a clean
analog ground. Any good quality ceramic or tantalum can
be used for this capacitor. The capacitor with larger value
and lower ESR (equivalent series resistance) provides
better PSRR and line-transient response. The output
capacitor must meet both requirements for minimum
amount of capacitance and ESR in all LDOs application.
The RT9193 is designed specifically to work with low ESR
ceramic output capacitor in space-saving and performance
consideration. Using a ceramic capacitor whose value is
at least 1μF with ESR is
ensures stability. The RT9193 still works well with output
capacitor of other types due to the wide stable ESR range.
Figure 1 shows the curves of allowable ESR range as a
function of load current for various output capacitor values.
Output capacitor of larger capacitance can reduce noise
and improve load transient response, stability, and PSRR.
The output capacitor should be located not more than 0.5
inch from the V
clean analog ground.
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8
0.001
0.01
100
Region of Stable C
0.1
10
1
0
OUT
50
pin of the RT9193 and returned to a
100
Load Current (mA)
Figure 1
OUT
>1mΩ on the
Instable
Stable
150
ESR vs. Load Current
RT9193-15xU5
C
IN
= C
200
OUT
RT9193 output
= 1μF, X7R
250
300
Bypass Capacitor and Low Noise
Connecting a 22nF between the BP pin and GND pin
significantly reduces noise on the regulator output, it is
critical that the capacitor connection between the BP pin
and GND pin be direct and PCB traces should be as short
as possible. There is a relationship between the bypass
capacitor value and the LDO regulator turn on time. DC
leakage on this pin can affect the LDO regulator output
noise and voltage regulation performance.
Enable Function
The RT9193 features an LDO regulator enable/disable
function. To assure the LDO regulator will switch on, the
EN turn on control level must be greater than 1.2 volts.
The LDO regulator will go into the shutdown mode when
the voltage on the EN pin falls below 0.4 volts. For to
protecting the system, the RT9193 have a quick-discharge
function. If the enable function is not needed in a specific
application, it may be tied to V
in a continuously on state.
Thermal Considerations
Thermal protection limits power dissipation in RT9193.
When the operation junction temperature exceeds 165°C,
the OTP circuit starts the thermal shutdown function turn
the pass element off. The pass element turn on again
after the junction temperature cools by 30°C.
For continue operation, do not exceed absolute maximum
operation junction temperature 125°C. The power
dissipation definition in device is :
P
The maximum power dissipation depends on the thermal
resistance of IC package, PCB layout, the rate of
surroundings airflow and temperature difference between
junction to ambient. The maximum power dissipation can
be calculated by following formula :
P
Where T
temperature 125°C, T
the θ
D
D(MAX)
= (V
JA
IN
= ( T
is the junction to ambient thermal resistance.
− V
J(MAX)
J(MAX)
OUT
) x I
is the maximum operation junction
− T
OUT
A
A
) /θ
is the ambient temperature and
+ V
JA
IN
IN
x I
DS9193-13 January 2011
to keep the LDO regulator
Q