RHFL4913A STMICROELECTRONICS | Alldatasheet
Document overview
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- PDF pages: 20
Technical content
Datasheet sections
- 1 Diagram
- 2 Pin configuration
- 3 Maximum ratings
- 4 Electrical characteristics
- 5 Device description
- 5.1 ADJ pin
- 5.2 Inhibit ON-OFF control
- 5.3 Overtemperature protection
- 5.4 Overcurrent protection
- 5.5 OCM pin
- 5.6 Alternatives to the RHFL4913A
- 6 Application information
- 6.1 Notes on the 16-pin hermetic package
- 6.2 Remote sensing operation
- 6.3 FPGA power supply lines
- 7 Die information
- 7.1 Die bonding pad locations and electrical functions
- 8 Package mechanical data
- 9 Packaging
- 10 Ordering information
- 11 Revision history
Features
■ 3 A low dropout voltage ■ Embedded overtemperature and overcurrent protection ■ Adjustable overcurrent limitation ■ Output overload monitoring/signalling ■ Adjustable output voltage ■ Inhibit (ON/OFF) TTL-compatible control ■ Programmable output short-circuit current ■ Remote sensing operation ■ Rad-hard: guaranteed up to 300 krad Mil Std 883E Method 1019.6 high dose rate and 0.01 rad/s in ELDRS conditions ■ Heavy ion, SEL immune
Description
The RHFL4913A high-performance adjustable positive voltage regulator provides exceptional radiation performance. It is tested in accordance with Mil Std 883E Method 1019.6, in ELDRS conditions. The device is available in the FLAT -16 and the new SMD5C hermetic ceramic package, and the QML-V die is specifically designed for space and harsh radiation environments. It operates with an input supply of up to 12 volts. The RHFL4913A is QML-V qualified, DSCC SMD #5962F02524. FLAT-16 SMD5C: 5-connection SMD
1 Diagram
Figure 1. Block diagram
2 Pin configuration
Figure 2. Pin configuration (top view for FLAT-16, bottom view for SMD5C) Table 1. Pin description
3 Maximum ratings
Table 2. Recommended maximum operating ratings (1)
- Exceeding maximum ratings may damage the device.
Table 3. Thermal data
4 Electrical characteristics
TJ = 25 °C, VI = VO + 2.5 V, CI = CO = 1 µF , unless otherwise specified. Table 4. Electrical characteristics
- These values are guaranteed by design. For each application it is strongly recommended to comply with the maximum
current limit of the package used. Table 4. Electrical characteristics (continued) Figure 3. Application diagram for remote sensing operation
Device description RHFL4913A 8/20 Doc ID 10005 Rev 11
5 Device description
The RHFL4913A adjustable voltage regulator contains a PNP type power element controlled by a signal resulting from an amplified comparison between the internal temperature-compensated band-gap and the fraction of the desired output voltage value obtained from an external resistor divider bridge. The device is protected by several functional blocks.
5.1 ADJ pin
The load output voltage feedback comes from an external resistor divider bridge mid-point connected to the ADJ pin (allowing all possible output voltage settings as per user requirements) established between load terminals.
5.2 Inhibit ON-OFF control
By setting the INHIBIT pin TTL high, the device switches off the output current and voltage. The device is ON when the INHIBIT pin is set low. Since the INHIBIT pin is pulled down internally, it can be left floating in cases where the inhibit function is not used.
5.3 Overtemperature protection
A temperature detector internally monitors the power element junction temperature. The device turns off when a temperature of approximately 175 °C is reached, returning to ON mode when back to approximately 135 °C. Combined with the other protection blocks, the device is protected from destructive junction temperature excursions in all load conditions. It should be noted that when the internal temperature detector reaches 175 °C, the active power element can be as high as 225 °C. Prolonged operation under these conditions far exceeds the maximum operating ratings and device reliability cannot be guaranteed.
5.4 Overcurrent protection
An internal non fold-back short circuit limitation is set with ISHORT > 3.8 A (VO is 0 V). This value can be decreased via an external resistor connected between the ISC and VI pins, with a typical value range of 10 kΩ to 200 kΩ. To maintain optimal VO regulation, it is necessary to set ISHORT 1.6 times greater than the maximum desired application IO. When IO reaches ISHORT – 300 mA, the current limiter overrules the regulation, VO starts to drop and the OCM flag is raised. When no current limitation adjustment is required, the ISC pin must be left unbiased (as it is in 3 pin packages).
5.5 OCM pin
The OCM pin goes low when the current limit becomes active, otherwise VOCM = VI. It is buffered and can sink 10 mA. The OCM pin is internally pulled up by a 5 kΩ resistor.
RHFL4913A Device description Doc ID 10005 Rev 11 9/20
5.6 Alternatives to the RHFL4913A
The adjustable RHFL4913A is recommended to replace all industry positive voltage regulators due to its exceptional radiation performance. To replace 3-terminal industry devices, the fixed voltage versions of the RHFL4913A should be used.
6 Application information
To adjust the output voltage, the R2 resistor must be connected between the VO and ADJ pins. The R1 resistor must be connected between ADJ and ground. Resistor values can be derived from the following formula: VO = VADJ (R1+ R2) / R1 The VADJ is 1.23 V, controlled by the internal temperature-compensated band gap block. The minimum output voltage is therefore 1.22 V and minimum input voltage is 3 V. The RHFL4913A adjustable is functional as soon as the V I - VO voltage difference is slightly above the power element saturation voltage. The adjust pin to ground resistor value must not be greater than 10 kΩ, in order to keep the output feedback error below 0.2%. A minimum of 0.5 mA I O must be set to ensure perfect no-load regulation. It is advisable to dissipate this current into the divider bridge resistor. All available VI pins, as well as all available VO pins, should always be externally interconnected, otherwise the stability and reliability of the device cannot be guaranteed. The inhibit function switches off the output current electronically, and therefore very quickly. According to Lenz’s Law, external circuitry reacts with LdI/dt terms which can be of high amplitude in case somewhere a serial coil inductance exists. Large transient voltage would develop on both device terminals. It is advisable to protect the device with Schottky diodes to prevent negative voltage excursions. In the worst case, a 14 V Zener diode could protect the device input. The device has been designed for high stability and low dropout operation. Therefore, tantalum input and output capacitors with a minimum 1 µF are mandatory. Capacitor ESR range is from 0.01 Ω to over 20 Ω. This range is useful when ESR increases at low temperature. When large transient currents are expected, larger value capacitors are necessary. In the case of high current operation with short circuit events expected, caution must be exercised with regard to capacitors. They must be connected as close as possible to the device terminals. As some tantalum capacitors may permanently fail when subjected to high charge-up surge currents, it is recommended to decouple them with 470 nF polyester capacitors. Since the RHFL4913A adjustable voltage regulator is manufactured with very high speed bipolar technology (6 GHz f T transistors), the PCB layout must be designed with exceptional care, with very low inductance and low mutually coupling lines. Otherwise, high frequency parasitic signals may be picked up by the device resulting in system self-oscillation. The benefit is an SVR performance extended to far higher frequencies.
6.1 Notes on the 16-pin hermetic package
The bottom section of the 16-pin package is metallized in order to allow the user to directly solder the RHFL4913A onto the equipment heat sink for enhanced heat removal.
6.2 Remote sensing operation
A separate kelvin voltage sensing line provides the ADJ pin with exact load "high potential" information (see Figure 3). But variable remote load current consumption induces variable Iq current (Iq is roughly the IO current divided by the hFE of the internal PNP series power element) routed through the parasitic series line resistor RW2. To compensate for this
parasitic voltage, resistor RW1can be introduced to provide the necessary compensating voltage signal to the ADJUST pin.
6.3 FPGA power supply lines
Because these devices are very sensitive to VDD transients beyond a few % of their nominal supply voltage (usually 1.5 V), special attention must be given by supply lines designers to mitigate possible heavy ion L4913 disturbances. The worst case heavy ion effect can be summarized as: the L4913 internal control loop being cut (made open) or short-circuited for a sub-microsecond duration. During such an event, the L4913 die power element can either provide excessive current or current supply stoppage to the output (V OUT) for a duration of about one microsecond, after which time the L4913 smoothly recovers to nominal operation. To mitigate these "transients", it is recommended to implement the L4913 PCB layout as follows:
- Minimizing series/parallel parasitic inductances of the PC path
- Using a low ESR 47 µF Tantalum VOUT filtering capacitor with a 470 nF ceramic capacitor in parallel with the former (to reduce dynamic ESR)
- Inserting a 100-200 nH ferrite core on the VOUT-to-tantalum capacitor wire With this implementation, the ELDO simulated worst transient case shows no more than 90 mV deviation from the nominal line voltage value.
7 Die information
Note: Pad numbers reflect terminal numbers when placed in case FLAT -16. Figure 4. Die map
7.1 Die bonding pad locations and electrical functions
Die physical dimensions: Die size: 150 mils x 110 mils (3.81 mm by 2.79 mm) Die thickness: 375 µm ± 25 µm (14.8 mils ± 1 mil) Pad size: V IN, VOUT pads: 450 µm x 330 µm (17.7 mils by 13 mils) Control pads: 184 µm x 184 µm (7.25 mils square) Interface materials: Top metallization: Al/Si/Cu, 1.05 µm ± 0.15 µm Backside metallization: none Glassivation: Type: p. vapox + nitride Thickness: 0.6 µm ± 0.1 µm + 0.6 µm ± 0.08 µm Substrate: bare silicon Assembly related information: Substrate potential: floating recommended to be tied to ground Special assembly instructions: "Sense" pad not used; not internally connected to any part of the IC. Can be connected to ground when space anti-static electricity rules apply.
8 Package mechanical data
In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions and product status are available at: www.st.com. ECOPACK® is an ST trademark.
Dim. mm. inch. A 2.16 2.72 0.0 85 0.107 b 0.43 0.017 c0 . 1 3 0.005 D 9.910 . 390 E6 . 91 0.272 E2 4. 32 0.170 E3 0.76 0.0 30 e 1.27 0.050 L 6.72 0.265 Q 0.66 1.14 0.026 0.045 S1 0.1 3 0.005 FLAT-16 (MIL-STD-1835) mechanical data 7450901A 1 8 e b c L E D S1 Q A L
Dim. mm. inch. D1 0.76 0.0 30 e1 . 91 0.075 SMD5C mechanical data 7924296B
9 Packaging
The RHFL4913A adjustable voltage regulator is available in a high thermal dissipation 16- pin hermetic Flat package, the bottom flange of which is metallized to allow direct soldering to a heat sink (efficient thermal conductivity). The device is also available in the SMD5C hermetic ceramic package.
Table 5. Order codes RHFL4913KPA2 RHFL4913SCA2 Gold Adj EM2=EM1+48hours B.I. Table 6. Part numbers - SMD equivalent Table 7. Environmental characteristics
Table 8. Document revision history 29-Oct-2004 3 New order codes added - Tables 4 and 5. 30-Jan-2006 6 Added new package SMD5C and removed old package SOC-16. 26-Jan-2007 7 DIE Information and DIE Pad has been updated par. 6, pages 9 and 10. FPGA power supply lines on page 11. Minor text changes. 22-Sep-2008 9 Modified Application information on page 10. 17-Nov-2008 10 Modified Table 6 on page 18. 21-Jan-2010 11 Modified Table 5 on page 18.